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2004 Performance of Individuals with Alzheimer-Type Profiles Gina L. Youmans

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THE FLORIDA STATE UNIVERSITY

COLLEGE OF COMMUNICATION

THEORY OF MIND PERFORMANCE OF INDIVIDUALS

WITH ALZHEIMER-TYPE DEMENTIA PROFILES

By

GINA L. YOUMANS

A Dissertation submitted to the Department of Communication Disorders in partial fulfillment of the requirements for the degree of Doctor of Philosophy

Degree Awarded: Summer Semester, 2004

Copyright © 2004 Gina L. Youmans All Rights Reserved

The members of the Committee approve the dissertation of Gina L. Youmans defended on June 15, 2004.

Michelle S. Bourgeois Professor Directing Dissertation

Michael E. Rashotte Outside Committee Member

Howard Goldstein Committee Member

Leonard L. LaPointe Committee Member

Approved:

Howard Goldstein, Chair, Department of Communication Disorders

John K. Mayo, Dean, College of Communication

The Office of Graduate Studies has verified and approved the above named committee members.

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TABLE OF CONTENTS

List of Tables …………………………………………………………………………… v Abstract ………………………………………………………………………....… vii

1. LITERATURE REVIEW …………………………………………………………… 1 Theory of Mind………………………………………………………………….. 1 Theories of Theory of Mind……………………………...……………………… 4 Theory of Mind Assessment………………………………………..…………… 8 Acquired Theory of Mind Impairment in Neurogenic Populations…...………… 12 Summary of Evidence for Theory of Mind Impairment………………………… 29

2. INTRODUCTION …………………………………………………………………… 37

Theory of Mind………………………………………………………………….. 37 Purpose……………………………………………...…………………………… 43

3. METHOD …………………………………………………………………………… 45

Participants …………………………………………………………………… 45 Design …………………………………………………………………………… 54 Experimental Stimuli …………………………………………………………… 54 Procedures …………………………………………………………………… 57 Data Coding and Scoring …………………………………………………… 59 Reliability …………………………………………………………………… 60 Data Analysis …………………………………………………………………… 62

4. RESULTS …………………………………………………………………………… 65

Theory of Mind Impairment in AD Participants………………………………… 65 Error Pattern Analysis for Theory of Mind Testing…...………………………… 67 Error Analysis of ToM Inconclusive Trials……………………………………… 73 Correlations Between Theory of Mind Scores and Neurocognitive Tests…….… 73 Case Summaries of Results for Individual AD Participants……………..…….… 77

5. DISCUSSION …………………………………………………………………… 82

Evidence of Theory of Mind Impairment in AD Participants…………………… 82

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Effect of Support on Theory of Mind Performance ……...…………… 83 Individual Case Analyses…………………………..…………………………… 86 ToM Inconclusive Trials…………………………...…………………………… 89 Coincidence of Cognitive Impairments with Theory of Mind Impairment…...… 89 Conclusions………………………………………...…………………………… 91 Study Limitations and Future Research……..……...…………………………… 92

APPENDIX A. Example Story and Scoring for Initial Reading Screening …………… 95

APPENDIX B. First Order False Belief Scenarios…….……………….……………… 99

APPENDIX C. Second Order False Belief Scenarios.……………….………………… 104

APPENDIX D. D. Scoring Protocols………………………..………………………… 111

APPENDIX E. Individual Case Data for AD Participants………………...…………… 114

APPENDIX F. Subjects Approval Letter…….………………………………… 156

APPENDIX G. Informed Consent Form……………………………………………….. 158

REFERENCES …………………………………………………………………… 164

BIOGRAPHICAL SKETCH …………………………………………………………… 172

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LIST OF TABLES

1. AD Participant Characteristics, MMSE Scores and RCF Profiling Scores ..… 50

2. AD Profiles on DRS-2 ……………………………………..…………………… 51

3. Control Group Demographics and Cognitive Test Scores ..………………… 53

4. Inter-rater Reliability for Theory of Mind and Neurocognitive Tests ...... ……… 63

5. First Order, Second Order, and Combined ToM Trial Scores ……………….… 66

6. Number of ToM Pass, Impairment and Inconclusive Trial Scores ………..… 67

7. Frequency of Referral to Story Text During Supported Condition ….…….… 69

8. Group Total Error Scores, and Group Question-type Specific Error Scores …. 70

9. Individual Total Error Scores on Theory of Mind Testing .……………..…… 72

10. Correlations between ToM scores and neurocognitive test scores ………….. 74

11. Scores of AD participants on neurocognitive instruments …………...... …… 76

12. Scores of AD participants on test of executive functioning …………………... 77

13. Theory of Mind Test Results for AD Participant # 1 ………………...………… 116

14. Neurocognitive Test Scores for AS # 1 …………………………………..……… 117

15. Theory of Mind Test Results for AD Participant # 2 ………………………..… 120

16. Neurocognitive Test Scores for AS # 2 ……………………………………..…… 121

17. Theory of Mind Test Results for AD Participant # 3 ………………………..… 124

18. Neurocognitive Test Scores for AS # 3 ……………………………………..…… 125

19. Theory of Mind Test Results for AD Participant # 4 ………………………… 128

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20. Neurocognitive Test Scores for AS # 4 ………………………………………..… 129

21. Theory of Mind Test Results for AD Participant # 5 ………………………..… 132

22. Neurocognitive Test Scores for AS # 5 …………………………………………… 133

23. Theory of Mind Test Results for AD Participant # 6 …………………………… 136

24. Neurocognitive Test Scores for AS # 6 …………………………………………… 137

25. Theory of Mind Test Results for AD Participant # 7 …………………………… 140

26. Neurocognitive Test Scores for AS # 7 …………………………………………… 141

27. Theory of Mind Test Results for AD Participant # 8 …………………………… 144

28. Neurocognitive Test Scores for AS # 8 …………………………………………… 145

29. Theory of Mind Test Results for AD Participant # 9 …………………………… 148

30. Neurocognitive Test Scores for AS # 9 …………………………………………… 149

31. Theory of Mind Test Results for AD Participant # 10 …………………………… 152

32. Neurocognitive Test Scores for AS # 10 …………………………………………… 153

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ABSTRACT

Theory of Mind (ToM) involves a person’s ability to infer what another person knows, thus taking his or her perspective. Initial evidence has been presented for a ToM impairment in individuals with mild to moderate Alzheimer’s disease (AD), however preliminary investigations have failed to dissociate theory of mind difficulty from impairments in general inferencing, executive functions, and . Deficits in any of these areas could be sufficient to explain the apparent ToM impairment in the AD population. Ten participants with mild to moderate AD profiles completed first order and second order false belief tasks with and without memory support, and their performances on ToM testing were compared to the performances of elderly controls. All theory of mind testing was controlled with memory, comprehension, and general inferencing questions, and AD participants completed neuropsychological testing to concurrently assess general cognitive functioning, memory, and executive functioning. Independent and paired t-tests compared experimental and control group ToM performances. Correlations assessed relations between ToM and neurocognitve test performances. Descriptive statistics were calculated, and individual case analyses for performances of AD participants were presented. Results indicated that AD participants did not exhibit a specific ToM difficulty as compared to control participants when support for memory was not provided. However, significant group differences for specific ToM impairment that appeared to be separable from comprehension, memory and general inferencing difficulties emerged during ToM testing when support for memory was provided. On individual case analysis, eight of the ten AD participants exhibited a mild, specific ToM difficulty. Correlations between ToM performance and neurocognitive test performances were not significant; however four of the eight AD participants

vii who exhibited specific, ToM difficulty also had difficulty with executive function testing. The results of the current study indicate that individuals with mild to moderate AD may possess an underlying, mild, specific ToM impairment which becomes apparent during supported memory testing. Such mild ToM impairment in high to moderate AD individuals must be further investigated, and possible contributions of executive function impairments to apparent ToM difficulty further explored before the current results can be confidently generalized to a larger AD population.

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CHAPTER 1 LITERATURE REVIEW

Theory of Mind

Theory of mind is the ability to represent mental states, such as beliefs, intentions and desires, and to use these abstract representations to guide and form one’s own actions and beliefs. Theory of mind allows one to attribute mental states to others: to understand that other people may hold and act upon beliefs different from one’s own. This appreciation of alternate perspectives is crucial for successful social interaction and communication. It underlies the ability to comprehend and predict the behavior of other people, and to interpret the actions of others as meaningful and intentional (Rowe, Bullock, Polkey, & Morris, 2001; Wellman & Wolley, 1990). The view of the human mind as an intentional agent that contains mental states such as beliefs and desires is not new. Such distinguished historical theorists as Descartes (1637), Freud (Brook, 1992), and Piaget (1945; 1962) have wrestled with the genesis and development of this distinction between the mental world of the self and the mental world of others. However, the conceptualization of this mentalizing ability as a specific skill, distinct from other cognitive functions, and the term “theory of mind”, have emerged relatively recently from the fields of philosophy (Dennet, 1978) and (Premack & Woodruff, 1978). Theory of Mind Impairment Because theory of mind is currently conceived of as a specialized skill, it follows that such a specific skill could be selectively impaired, with marked social- communicative consequences. Specific impairment of theory of mind has been studied most extensively in children with autism. Theory of mind impairment has been implicated as a core deficit in autism, and the social-communicative difficulties indicative of autism have generally been ascribed to theory of mind impairment. These include

1 poor social judgment, general paucity of social interaction, emotional indifference, poor conversational pragmatic skills, and difficulty comprehending abstract, non-literal language (Baron-Cohen & Ring, 1994). Relatively recently, researchers have begun to ascribe similar social- communication difficulties in certain adult populations with acquired neurologic damage to a specific theory of mind impairment. Individuals with traumatic brain injury, right hemisphere disorder, and dementia frequently exhibit social-communication impairments similar to those displayed by individuals with autism. Social-communicative deficits typical of these neurogenic populations include decreased social appropriateness, difficulty producing and comprehending complex discourse, decreased empathy, difficulty with logical thinking, and poor understanding of nuances of human communication, such as irony, humor, and sarcasm (Baron-Cohen & Ring, 1994; Damasio, 1994). Citing these similar behavioral impairment profiles as their impetus, many investigators have examined individuals with these neuropathologies for specific theory of mind impairment (Baron-Cohen & Ring, 1994; Mattson & Levine, 1990; Stone, Baron-Cohen, & Knight, 1998). There are several gains that may be made from the examination of theory of mind abilities in individuals with acquired, neurologic damage. These investigations may establish the presence or absence of a specific theory of mind deficit in a given neurogenic population, and, therefore, advance understanding of underlying causes of behavioral impairments in the population of interest. If poor theory of mind ability underlies the social-communicative difficulties of individuals with a specific acquired neurologic disorder, then a shift from the current, more cognitive-general understanding of these difficulties to a theory of mind-specific interpretation of the impairment may be indicated. In addition, establishment of theory of mind involvement might suggest an intervention focused on repairing or supporting mental state inferencing abilities, rather than, or in addition to, a more holistic cognitive, or executive function-based intervention. In addition, theory of mind investigations of neurogenic populations may help identify neural structures that support theory of mind ability. Several researchers have attempted to identify neural structures important to theory of mind by correlating lesion locations with relative theory of mind impairment (Rowe, Bullock, Polkey, & Morris,

2 2001; Stuss, Gallup, & Alexander, 2001; Winner, Brownell, Happe, Blum, & Pincus, 1998). Also to this end, some investigators have completed functional brain imaging studies with normal adult populations. These studies generally examine brain region activity during theory of mind tasks, and have the potential to augment the evidence for theory of mind-specific brain regions derived from investigations of neurogenic populations. (Fletcher, Happe, Frith, Baker, Dolan, & Frackowiak, 1995; Goel, Grafnam, Sadato, & Hallett, 1995). The study of theory of mind impairment in populations with acquired neurogenic disorders also has the potential to support or to refute different theoretical explanations of theory of mind ability. Localization of specific neural structures that support theory of mind may impact understanding of the theory of mind construct itself, and, certainly, theorists have interpreted studies of adult neurogenic populations to this end. In addition, discovery of specific theory of mind impairment in various neurogenic populations may add credibility to the concept of theory of mind as a specialized skill, separable from other cognitive skills. This is a concept that continues to be contested in the theory of mind literature (Hughes, Russell, & Robbins, 1994; Ozonoff, Pennington, & Rogers, 1991). The recent expansion of theory of mind investigation to individuals with acquired neurogenic disorders may not only improve our understanding of the social and communicative deficits of these populations, it may increase our understanding of the theory of mind construct itself. Therefore, it is appropriate to review the theory of mind studies of acquired neurogenic populations that have been completed. The following review of this literature will assess whether theory of mind impairment has been established in various neurologically compromised populations, whether theory of mind ability has been successfully localized to specific neural structures, and the impact this literature has had on the underlying theoretical construct of theory of mind. To allow a thorough discussion of these issues, it is necessary first to review different theoretical explanations of theory of mind, and then to briefly review and critique different tasks and assessments that have been used to measure theory of mind.

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Theories of Theory of Mind

Although the core definition of theory of mind holds fairly constant, the structure and processes of this mental state attribution ability have been described from radically different theoretical perspectives. In addition, some theorists argue that a distinct theory of mind skill need not be invoked at all, but rather that mental state attribution can be completely and more parsimoniously accounted for by general cognitive mechanisms, such as executive functions. It is important to understand the different theories of theory of mind, because each makes different predictions about the nature of mentalizing ability. In addition, these theories support different claims about the existence of specific neural structures that might subserve theory of mind, and neurological evidence may be interpreted differently by different theories. Modular Theory of Theory of Mind Modular theorists claim that theory of mind exists as a distinct, cognitive ability that is functionally dissociable from other cognitive functions. In addition, many modular theorists assert that the theory of mind module is innate, follows a pre-set developmental course, and matures relatively independently from other cognitive skills (Baron-Cohen, 1995; Leslie & Roth, 1993). The view of theory of mind as a domain-specific cognitive module has emerged from the study of autism (Baron-Cohen, Leslie, & Frith, 1985; Leslie & Thaiss, 1992). Researchers have found theory of mind to be selectively impaired relative to other high- level cognitive functions, including linguistic abilities and executive functions, in individuals with autism and individuals with Asperger’s syndrome. (Baron-Cohen, 1995; Frith & Frith, 1999; Leslie & Thaiss, 1992). In addition, theory of mind can be selectively spared relative to general cognitive functions in cases of Down’s syndrome and Williams’ syndrome (Karmiloff-Smith, Kilma, Bellugi, Grant, & Baron-Cohen, 1995). This double dissociation between theory of mind and other high-level cognitive skills provides strong evidence that theory of mind may indeed be a distinct, domain- specific skill, as modular theorists claim.

4 Further support for the domain-specificity of theory of mind comes from the study of normal development. Researchers have established a developmental stage sequence for theory of mind in children that appears to hold across cultures (Avis & Harris, 1991; Jin, Jing, Morinaga, Su, & Chen, 2002), is relatively independent of general intelligence, and is impaired or absent in children with autism (Leslie, 1987; Penner & Winner, 1985; Winner & Penner, 1983). In addition, recent evidence indicates that theory of mind may be selectively preserved, and even enhanced, in the normal elderly population, relative to memory and other cognitive-general abilities (Happe, Winner, & Brownell, 1998). Modular theorists have attempted to describe the operation of this theory of mind module. In this model, the theory of mind domain enables the logical representation and manipulation of truth and belief statements that may differ from one’s own, and allows the assignment of these various belief states to different intentional agents (Baren-Cohen, 1995; Leslie & Thaiss, 1992). This attribution of mental states depends upon meta- representational abilities: the ability to represent representations, such as the beliefs and desires, of others. It also requires the ability to simultaneously represent and to contrast the contradictory beliefs about the world that different individuals may hold. Modular theorists also make a clear distinction between inferencing about abstract mental states, which is a theory of mind skill, and inferencing about the physical world, which is considered to be a general inferencing skill, unrelated to theory of mind. In contrast to more cognitive-general theories, modular theory supports the existence of one or more neural structures specifically dedicated to theory of mind. If theory of mind is functionally dissociable from other cognitive abilities, then this mental skill may be localized in distinct neural structures, the ablation of which could create a deficit specific to theory of mind, while other cognitive skills remain relatively intact. Although modularity theory is not dependent upon such evidence, the identification of such theory of mind-dedicated neural areas would strongly suggest that theory of mind is indeed a distinct cognitive ability, and not simply derived from general inferencing abilities, executive functions, or other cognitive-general skills. Theory of Mind as a Simulation Simulation theorists propose that theory of mind ability, or attributing mental states to others, can be most accurately conceived of as an act of role-taking (Langdon &

5 Coltheart, 2001). From this perspective, individuals’ interpretations of the world are not guided by a general theory about how minds work, nor do individuals make inferences about the mental states of others, and thereby predict actions. Instead, individuals simulate what reality would look like to another person by mentally placing themselves into that person’s perspective, and then predicting what they themselves would do in the other person’s place. Simulation theory does not differentiate between abstract, cognitive perspective-taking and concrete, visual perspective-taking that involves mental manipulation of a physical environment. This is in opposition to modular theories, which clearly differentiate mental state inferences from inferences about the concrete, physical world. In addition, simulation theory does not require the meta-representational computations about reality that are imposed by some modular theorists (Leslie & Roth, 1993). Little empirical evidence exists for this general perspective taking, simulation theory. In fact, investigators have repeatedly demonstrated that visual perspective-taking ability remains intact in autistic individuals with theory of mind impairment (Baren- Cohen et al., 1993). However, Langdon and Coltheart (2001) have recently criticized commonly used visual perspective-taking assessments as lacking the sophistication needed to reveal true visual perspective-taking difficulty. Using a more fine-grained analysis of visual perspective-taking, these investigators demonstrated impaired visual perspective-taking ability in a group of theory of mind-impaired, schizotypal individuals who passed traditional visual perspective-taking tasks. If these results are replicated and prove to be robust, and theory of mind impairment does indeed frequently co-exist with more general, physical perspective-taking difficulties, the simulation theory claim that the specialized skill of mental state attribution may depend upon general perspective-taking ability may gain new credibility. Due to this more general, perspective-taking view of mentalizing, simulation theory does not predict the existence of a specialized, distinct neural architecture for theory of mind ability, the ablation of which could selectively impair theory of mind. Rather, simulation theory seems to predict that impairment of neural structures that support more general perspective-taking ability would significantly disrupt theory of mind.

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Theory of Mind as a Developing Theory. The theory-theory views theory of mind as a developing, evolving theory about other minds that is revised with experience over time. This theoretical stance posits several different theories of mind that replace one another as an individual’s appreciation of alternate, cognitive perspectives becomes increasingly more sophisticated (Gopnik & Wellman, 1994). Theory-theory holds that theory of mind is not an innate ability, however it may be based upon an innate, general theory formation mechanism, or even on an innate, primitive, mind-oriented, starting-state theory (Gopnik, Capps & Meltzoff, 2000). Theory-theory does not view theory of mind as a specific cognitive module, but rather as a specialized, cognitive skill dependent on the operation of more general inferential abilities, and perhaps dependent upon general theory-formation mechanisms as well (Gopnik et al., 2000). Because theory-theory does not posit a modular theory of mind ability, separable from more cognitive-general processes, it does not support a specific, dedicated neural system for theory of mind. Like simulation theory, theory-theory seems to presume that damage to neural structures that support more general inferencing or theory formation abilities would impair theory of mind. Executive Function-based Explanation of Theory of Mind. Modular theory, simulation theory, and theory-theory disagree on the degree to which theory of mind is dependent upon more general cognitive abilities; however, these theories all posit a specialized theory of mind skill that allows the understanding of other minds, and that is crucial for normal social interaction and communication. In contrast, some theorists contend that a distinct theory of mind ability does not exist. These theorists instead believe that executive functions are sufficient to perform the mental inferencing skills attributed to theory of mind, without the invocation of any specialized cognitive skill (Hughes et al, 1995; Ozonoff et al., 1991). These theorist that reject a theory of mind construct argue that the tasks traditionally used to assess theory of mind ability primarily test executive function component skills such as set-shifting and response inhibition. For example, an individual might fail to inhibit a response based upon his own beliefs, and so fail to display his actually intact appreciation of an

7 alternative perspective held by another person. These cognitive-general theorists further claim that the core, meta-representation ability attributed to theory of mind by modularity theorists is merely one example of the general executive capacity for using embedded rules (Frye, Zelazno, & Palfai,1995). Supporters of this executive function explanation point to evidence of similar executive function and theory of mind developmental timelines in children, and to the difficulty inherent in differentiating theory of mind skills from executive function skills. These theorists have also presented evidence that executive function performance predicts theory of mind performance, while theory of mind performance does not predict executive function performance. This suggests that theory of mind is dependent on executive functions while executive functions are not dependent on any theory of mind skill (Frye et al., 1995; Hughes, 1998; Ozonoff et al., 1991). Because this executive function explanation contends that a specialized theory of mind does not exist, it predicts that a dedicated, theory of mind neural architecture also does not exist, and that selective impairment of theory of mind with sparing of executive function skills is not possible. Consequently, convincing evidence of specific localization of theory of mind ability, or of selective theory of mind impairment with spared executive function component skills in neurological lesion studies should contradict the claims of this theory. These four different theoretical approaches obviously embrace widely different views of the concept of theory of mind, from the modular theory, which posits a specific module that is completely separable from general cognitive functions, to executive function-based explanations, which consider theory of mind to be completely accounted for by general cognitive functions. Although they do not differ as widely, different approaches to the assessment of theory of mind ability have also evolved, and these different assessment techniques may also impact the general understanding of mental state inferencing ability.

8 Theory of Mind Assessment

Over the past three decades, several methods for the assessment of theory of mind have been developed. Tests of false belief were originally proposed by Dennett (1978) as a method of conclusively demonstrating that an individual is able to ascribe mental states to others. False beliefs are used because it is necessary to establish that an individual being tested is able to attribute beliefs to others that are different from his own beliefs. Tests of false beliefs are the most established, and the most theoretically valid method of establishing theory of mind ability or impairment. First order false belief tests establish whether an individual can correctly predict the actions of a character based upon attribution to that character of a false belief. For example, an individual might observe a character, Sara, moving a cookie from its hiding place once a second character, Jim, has left the room. The individual completing the false belief-task would display intact first order false belief attribution if he predicted that Jim, upon re-entering the room, would look for the cookie in its old location rather than it’s new hiding place. In order to make this correct prediction, the individual must be able to look past, or inhibit, his own knowledge of reality, and rely instead on his understanding of the false belief held by another person. Children can correctly make first order false belief mental state attributions at three to four years of age (Winner & Perner, 1983). Second order false belief tests are more difficult tasks that establish whether an individual can correctly attribute a false belief about a belief. For example, if unbeknownst to Sara (but known to the individual being tested) Jim peeked back into the room and observed Sara changing the hiding place of the cookie, Sara would then falsely believe that Jim believes the cookie is still hidden in its original location. Sara would hold a false belief about Jim’s belief. Children generally pass second order false belief tests at age six or seven (Perner & Winner, 1985). It is common for adults with autism to fail first and second order false belief tasks, while passing similar tests that involve representing false beliefs and making inferences about the physical world, rather than about mental states (Lesie & Thaiss, 1992; Zaitchile, 1990).

9 Other, more complex and subtle tests of theory of mind have been developed recently that involve the interpretation of abstract or non-literal language, a skill that may require appropriate mental state attribution. Investigators who use these more sophisticated tests of theory of mind claim that often, interpretation of non-literal language such as sarcasm, irony or deceit involves understanding what a speaker knows, believes, or intends (Baron-Cohen, O’Riordan, Stone, Jones, & Plaisted, 1997). These higher-level theory of mind tasks have taken several different forms. Happe (1993) used a task that required understanding irony and metaphor to measure high-level theory of mind impairment. Winner and colleagues (1998) developed a theory of mind assessment task that measured subjects’ ability to distinguish lies from jokes. Baron-Cohen and colleagues (1997) have established a faux pas task to assess similar high-level mental state attributions. In this faux pas task, an individual must understand why the speaker should not have said what he said (the faux pas), that the speaker does not realize that he has spoken in error, and why the listener would feel insulted or hurt. Sophisticated theory of mind tasks such as these are often more sensitive to high- level theory of mind impairment than are the relatively simple false belief tests. Subjects who perform adequately on first and second order false belief tasks have been shown to have specific difficulty with these high-level theory of mind tasks, while performing well on other cognitive measures (Stone, Baron-Cohen, & Knight, 1998). However, although these authors contend that such high-level tasks require attribution of mental states, the validity of these tasks as specific measures of theory of mind ability has yet to be established. Such tasks are confounded by a coincident increase in level of difficulty: they require the test taker to understand non-literal language, to infer implicit meanings, and to recognize and understand complex social situations. Although investigators generally attempt to control for confounding cognitive variables such as these, high-level theory of mind tasks require a level of complex cognitive skill that is very difficult to control for. It is therefore difficult to confidently identify a specific theory of mind impairment, rather than a more general cognitive or executive function impairment, on the basis of these high-level, non-literal language tasks. In addition to these abstract language tests, other assessments that deviate further from traditional false belief tasks have been used to assess theory of mind ability. For

10 example, Baron-Cohen and colleagues (1997) created a Reading the Mind in the Eyes task, in which subjects view a series of eye-region photographs, and select from given choices the emotion expressed in the eyes. This task has been frequently used as a theory of mind assessment, however the task of recognition of facial expression varies so drastically from attribution of mental states that it is not clear that this qualifies as a theory of mind task at all. In an equally non-traditional assessment Baron-Cohen and colleagues (1994) introduced a test of mental lexicon words purported to be a valid measure of theory of mind function, because individuals with autism perform poorly on this task (Baron-Cohen et al, 1997). In this task, subjects are presented with a list of words, and are asked to identify those words that refer to things the mind can do. Because this is a test of mental lexicon, rather than mental state attribution, it may have little relation to theory of mind ability. Performance on these tasks and other, non- traditional theory of mind tasks should be interpreted cautiously, as they may require alternative cognitive skills in addition to or instead of the attribution of mental states to others. In addition to employing specific theory of mind tasks, most studies that investigate such mental state attribution abilities in impaired populations also include additional tasks and/or questions that assess cognitive-general abilities such as working memory and general inferencing ability (usually established by inferences about the physical word rather than mental states). Fact recall and comprehension questions are also frequently included, to determine whether stimuli, such as task scenarios or written stories, have been understood by subjects. In addition, investigators that employ written or pictorial stimuli often allow subjects to refer back to the stimuli as needed when answering questions, to decrease task demands on working memory. Although not all theory of mind investigations include such controls for task comprehension, general (physical) inferencing ability, and working memory, such information is necessary to establish a primary theory of mind deficit. Subjects who display a theory of mind impairment that is dissociable from other cognitive skills can be most confidently diagnosed with a true, specific difficulty in making mental state attributions. As this brief review of assessment techniques illustrates, there is variation in the established validity of the different techniques used to assess theory of mind ability and

11 impairment. And, as mentioned, control questions that differentiate theory of mind from other cognitive functions are not always included in theory of mind investigations. The assessment tasks employed and control items included are particularly important variables to consider when assessing research studies that have expanded the investigation of theory of mind impairment from the autistic population, in which theory of mind impairment has been extensively researched, to populations with acquired neurogenic disorders.

Acquired Theory of Mind Impairment in Neurogenic Populations

Individuals with Frontal Lobe Damage. Researchers have presented strong support for the general localization of theory of mind to the frontal lobes (Rowe et al., 2001; Stone et al, 1998). The frontal lobes are likely candidates for housing theory of mind, because they are generally regarded as the seat of higher cognitive functions, including metacognitive functions, similar to theory of mind (Damasio, 1994). In addition, damage to the frontal lobes can affect high-level cognitive functions similar to theory of mind, such as social appropriateness, and can cause personality changes that may reflect a lack of empathetic perspective taking (Damasio, 1994). Damage specifically to the orbital-frontal and ventral-medial areas of the frontal cortex causes social and communicative difficulties such as impaired social judgment, impaired pragmatic skills, apathy, and difficulty with interpretation of social situations (Kaczmarek, 1984). Individuals with frontal lobe damage are one of the acquired neurogenic populations targeted recently for study by theory of mind researchers. It is common for such individuals, particularly those with damage to the prefrontal cortex, to present with social and communication difficulties similar to those seen in autism, such as poor social judgment, emotional indifference, poor self-monitoring, social withdrawl, and poor conversational pragmatic skills (Baron-Cohen & Ring, 1994; Mattson & Levine, 1990; Rowe et al., 2001). Citing these similarities as their impetus, Stone, Baron-Cohen and Knight, (1998) compared the performance of five traumatic brain-injured individuals with bilateral,

12 orbital-frontal cortex damage to the performance of five stroke patients with left dorsolateral-frontal cortex damage, and a group of five, normal control subjects. All study participants completed a series of developmentally graded theory of mind tests, beginning with first order false belief tasks and ending with complex faux pas tasks. The investigators controlled for general cognitive impairment by having subjects complete fact questions to establish general understanding of the characters and situations depicted in each scenario, and physical inference questions to establish general inferencing ability. The researchers also controlled for working memory load by providing written scenarios, available throughout testing, for the subjects to refer to at will. All groups performed well on first and second order false belief tasks, and on the physical inference and comprehension control questions associated with these. However, the traumatic brain- injured group did much worse on faux pas detection and interpretation than did either comparison group, even though this traumatic brain-injured group performed well on fact and physical inference control questions, indicating that they understood the faux pas situations and were capable of deriving inferences based upon given information. Stone and colleagues concluded that this difficulty in detecting social errors was caused by a specific deficit in theory of mind ability, and was consistent with the social inappropriateness and poor analysis of social situations frequently displayed by many individuals with traumatic brain injury in daily life. They further interpreted these results as evidence for the specific involvement of the left and right orbital-frontal regions in theory of mind functioning, and for the lack of involvement of the left dorsolateral region of the frontal cortex. Although this study employed well-established theory of mind tasks and adequate control questions, the claim for specific theory of mind impairment was based on poor performance on the faux pas task alone. This high-level task may be a less valid measure of theory of mind than the false belief tasks, and performance on this task may measure other, high-level cognitive abilities, such as executive functions. In addition, the sample size of five in each group is small, and so these results should be generalized cautiously. Further, three of the five subjects with left dorsolateral frontal cortex damage exhibited aphasia, and this language impairment makes the performance of this group difficult to interpret. For example, although these participants performed well on the mental state

13 inferencing questions associated with the faux pas situations, they performed poorly on the control questions associated with these stories, making it difficult to interpret their level of story comprehension, and their apparent ability to attribute mental states correctly to story characters. In another investigation of this population, Rowe and colleagues (2001) studied acquired theory of mind impairment in a group of patients with focal, frontal lobe damage following frontal lobe excision. These investigators presented six, first order false belief stories and six second order false belief stories to 15 subjects with right frontal lobe excision, 16 subjects with left, frontal lobe excision, and 31 normal, control subjects. In addition to mental state attribution questions, researchers included control questions to check for general story comprehension, memory for story details, and general inferencing ability. Rowe and colleagues reported evidence of theory of mind impairment on both first and second order tasks for these individuals with frontal lobe damage, regardless of whether damage occurred in the right or the left hemisphere. Participants in the disordered groups had significant difficulty with false belief questions, but performed well on all control questions, with the exception of those with left hemisphere damage, who had difficulty specifically with general inference control questions. The normal, control subjects had no difficulty on any part of the testing. In addition, Rowe and colleagues found this theory of mind impairment in subjects with frontal lobe damage to be independent of executive function performance, memory, verbal IQ, and general inferencing ability as measured by a battery of cognitive tests. These investigators interpreted these findings as strong support for an independent theory of mind module, separable from other cognitive skills and executive functions, and for the general localization of theory of mind to the right and left frontal lobes. This investigation does present strong evidence of a specific theory of mind deficit in individuals with frontal lobe damage, particularly in those individuals with right frontal damage. However, the authors’ claim for specific theory of mind impairment in the group with left hemisphere damage is less strong. This group’s poor performance on both mental and physical inference questions fails to dissociate theory of mind impairment from a deficit in general inferencing. In addition to this, a potential confound may be caused by the variation in pre-existing neuropathologies that originally

14 necessitated frontal lobe excision surgery. These may convolude the interpretation of this study, because any theory of mind impairment could potentially be due to these pre- existing neuropathological conditions. Stuss and colleagues (2001) completed a similar investigation of theory of mind in individuals with acquired brain damage with diverse etiologies, in which they also concluded that the frontal lobes are important for theory of mind. These investigators compared a group of 19 individuals with focal lesions in frontal lobe areas, to a group of 13 individuals with focal lesions in non-frontal areas, and to a group of 14, normal control subjects. All subjects participated in a series of three different interactive scenarios, in which they needed to correctly infer either the visual perspective or the mental state of a partner. When the task required the subject to infer his partner’s knowledge based upon his partner’s visual perspective or intentions, subjects with bi- frontal lesions and right frontal lesions made significantly more errors compared to normal control subjects, subjects with non-frontal lesions, and subjects with left frontal lesions only. The authors interpreted these results as evidence for a specific, modular theory of mind, whose component neural structures are housed at least partially in the frontal lobes, and possibly in the right frontal lobe in particular. Although the interactive theory of mind tasks used in this study are quiet creative, not one of the three alleged theory of mind tasks is clearly a mental inference task. Two are primarily visual perspective-taking tasks. In fact, these authors consider visual perspective-taking to be a component of theory of mind. In this, they differ from most other researchers who differentiate between concrete, visual perspective-taking and mental state attribution. The third task, a deception task, is clearly intended to be a mental state inferencing task, but is insufficient as an assessment of mental inferencing. In this task, a quarter is hidden under one of two cups, while the partner observes it being hidden. If the subject guesses wrong, the partner keeps the quarter and the subject receives nothing. The partner always gives the subject incorrect advice about which cup to choose, and the subject must realize that the partner is motivated to intentionally deceive in order to complete the task correctly. This task is significantly flawed as a measure of mental state inferencing ability, because the subject simply needs to realize that his partner is always wrong. This realization does not require a theory of mind, it

15 requires simple observational of a single rule from consistent feedback. In addition, the authors do not include control questions for comprehension, inferencing, or memory, nor do they administer any additional cognitive assessment to establish lack of impairment in these areas. There is little reason to attribute subject difficulty on these visual perspective-taking and deception tasks to theory of mind, rather than to general inferencing, memory, comprehension, or even rule learning difficulty. In another investigation of theory of mind impairment associated with frontal lobe damage, Happe and Mahli, and Checkly, (2001) assessed mental state attribution ability in an individual with acquired frontal lobe damage due to surgical stereotaxic anterior capsulotomy, a procedure that creates bilateral lesions in the anterior third of the internal capsule, specifically targeting connections between midline, limbic-associated thalamic nuclei and orbital-frontal cortex. Although this individual exhibited severe bipolar affective disorder, he performed at normal levels on cognitive testing prior to surgery, with the exception of below average performance on memory recall and recognition tasks. Following surgery, this individual exhibited general intellectual impairment, including significant memory loss and difficulty with frontal lobe executive functions such as set-shifting and response inhibition. He also became withdrawn with little emotional reactivity. These investigators compared the performance of this individual on a series of theory of mind tasks to that of 19 normal controls, and one control who exhibited bipolar affective disorder. Theory of mind was assessed with three previously established tests for theory of mind (Fletcher et al., 1995; Happe et al., 1994; Happe Brownell, & Winner, 1999). In task one, the story task, individuals read eight mental inference stories and eight physical inference stories, involving either double bluff, persuasion, white lie or mistake situations, and answered the mental inference or physical inference question that followed each story. Stories were not available for subjects to refer to while answering the questions, so working memory was not controlled for during this task. In task two, the single cartoon task, subjects explained why a series of single frame cartoons were funny. Half of these cartoons contained humorous elements that depended upon understanding what a character mistakenly or did not know, and half contained non-mental, physical humor. In task three, the cartoon pairs task, each single frame, mental inference or physical inference cartoon was paired with an altered

16 version of itself from which the humorous element was removed. Subjects were asked to point to the funny cartoon of each pair, and then explain what made the cartoon funny. The subject with anterior capsulotomy performed poorly on theory of mind tasks as compared to his own performance on control, physical inference tasks, and as compared to all control subjects. The authors interpret this as evidence for a distinct, modular theory of mind, and for the importance of bilateral, orbital-frontal regions in mental state attribution ability. The claims of this study, however, should also be somewhat qualified. Although the authors attempted to equalize the difficulty of mental inference and physical inference tasks, this is difficult to achieve and to ascertain. Non-mental tasks that involve physical causation are necessarily more concrete than the abstract, mental state tasks, and the abstract nature of mental inference tasks tends to make these inherently more difficult. Because the case subject exhibited general cognitive impairment post-surgery, it is certainly possible that his apparent difficulty with mental state attribution tasks reflected difficulty with abstract concepts, or with more complex tasks in general, rather than a specific theory of mind deficit. Alternatively, his poor executive function performance, particularly in response inhibition, might account for his poor performance on theory of mind tasks. In addition, no theory of mind testing was completed by this subject prior to his surgery. It is therefore impossible to compare his pre-surgical performance on theory of mind tests to his post-test performance, and, therefore, to confidently attribute his mental inferencing difficulty to his surgical lesion. Although his post-surgical personality change, and decreased social-communicative skills are consistent with the authors’ claim of a specific, surgery induced theory of mind impairment, the possibility remains that his mental state inferencing ability may have been compromised prior to surgery, from his very severe bipolar affective disorder, or from the aggressive treatment of this disorder that included electroconvulsive therapy. Although such a cause of theory of mind impairment would be interesting, it would not specifically implicate connections to the orbital-frontal region of the frontal lobes in theory of mind function. Taken together, these studies of individuals with frontal lobe injury provide an initial indication that theory of mind may indeed be a distinct, possibly modular, cognitive skill. Rowe and colleagues (2001) and Stone and colleagues (1998) present

17 generally well controlled studies that describe a significant disassociation between theory of mind and more cognitive-general functions. These two investigations also implicate damage to the frontal lobe in specific impairment of this ability to attribute mental states to others. Further, Rowe and colleagues present evidence for the specific involvement of the right frontal lobe in theory of mind (although not interpreted as such by these authors). This finding is consistent with evidence of theory of mind impairment in another neurogenic population, individuals with right hemisphere disorder. Individuals with Right Hemisphere Damage. Individuals with right hemisphere damage due to stroke are another population that has been recently investigated for theory of mind impairment. Like patients with traumatic brain injury and frontal lobe involvement, individuals with right hemisphere brain damage due to stroke exhibit deficits in social and pragmatic aspects of communication, and these deficits are similar to impairments seen in autism (Surian & Siegal, 2001). Individuals with right hemisphere disorder have difficulty deriving meaning from context, interpreting conversation, distinguishing internal emotional states, assuming varied perspectives, and recognizing the relevance of the theme of a narrative (Cicone,Wapner, & Gardner, 1980; Foldi, 1987; Kaplan, Brownwell, Jacobs, & Gardner, 1990). These deficits in communicative and social competence have traditionally been attributed to a general deficit in holistic processing of the right hemisphere, but, more recently, researchers have begun to attribute these deficits to specific social processing impairment of the anterior portion of the right hemisphere (McDonald, 1995). Alexander, Benson, and Stuss (1989) have proposed an anterior/posterior distinction for right hemisphere damage in which anterior damage results in social deficits because of difficulties in social reasoning, while posterior damage causes the more traditionally defined right hemisphere disorder, characterized by difficulties with the pragmatic aspects of language processing. This theoretical anterior basis for social aspects of right hemisphere damage is consistent with the observation that deficits in individuals with right, fronto-temporal damage due to stroke resemble deficits in individuals with theory of mind impairment, and with the general localization of theory of mind function to the frontal regions of the brain (Stone et al., 1998)

18 Happe, Brownell, and Winner (1999) investigated the theory of mind performance of a group of 14 individuals with right hemisphere damage due to stroke, the majority (12) of whom exhibited anterior, frontal lesions. The performance of this group was compared to that of five individuals with left hemisphere damage due to stroke, and to that of 19 normal control subjects. All subjects completed the short story task comprised of eight mental inference and eight physical inference stories, the single frame cartoon task, and the cartoon pairs task developed by Happe and colleagues (1994), and described in the aforementioned investigation (Happe et al., 2001). Demand for general inferencing, recognition of emotions and facial expressions, and integration of visual information was balanced across mental state inferencing tasks and the control, physical inferencing tasks, so that impairments in these cognitive areas might be ruled out as the cause of any observed theory of mind difficulties. These researchers found that the group with right hemisphere damage performed significantly worse on items requiring theory of mind skill than both normal, control subjects and subjects with left hemisphere damage. The right hemisphere group also had significantly more difficulty with mental state items than with the control, physical inferencing items on both the story task and the single frame cartoon task, indicating a specific theory of mind impairment relative to general inferencing, visual integration, and recognition of emotions and facial expressions. However, on the cartoon pairs task, the group with right hemisphere damage performed poorly on interpretation of both mental state and physical inference cartoons, and so failed to exhibit a theory of mind-specific deficit on this task. Because only individuals with right hemisphere damage were impaired on theory of mind tasks, these researchers concluded that theory of mind may be specifically housed in the right hemisphere, and that the social and communicative impairments exhibited by individuals with right hemisphere damage may be, at least in part, due to acquired, underlying impairments in attribution of mental states to others. These authors further suggest that theory of mind is indeed a specific, distinct, cognitive skill, separable from other general cognition and inferencing mechanisms. This reasonably sound, well conducted study does provide strong evidence that damage to the right hemisphere may lead to a specific theory of mind impairment, as opposed to a more general pragmatic or holistic processing disorder. However, the

19 evidence for anatomical localization of theory of mind to the right hemisphere specifically is less convincing. Only five individuals with left hemisphere damage were included, and this is a fairly small number of subjects from which to extrapolate to a more general population. Further, because these individuals with left hemisphere damage were aphasic, the testing was modified from a free response format to a forced choice format to reduce expressive language demands. The authors point out that this necessary modification may have been responsible for the group difference in theory of mind performance. The authors argue that the task of choosing the funny cartoon in the cartoon pairs is a not modified for participants with left hemisphere damage, and so allows direct comparison of theory or mind performance between these two groups. Although this is true, neither of the groups displayed a clear theory of mind impairment on this task, so no definitive claim of a right hemisphere-specific localization for theory of mind can be drawn from these test results. Although the theory of mind test battery includes more sophisticated short story scenarios and simple cartoons rather than traditional false belief tasks, these tasks have been fairly well established as measures specific to mental state attribution ability (Fletcher et al., 1995; Happe et al., 1994). However, because the right hemisphere-damaged group had difficulty with both mental and physical inference versions of the cartoon pairs task, it is possible that this relatively sophisticated task is measuring other cognitive skills such as visual integration or general inferencing, and not theory of mind specifically. In a related study, Winner, Brownell, Happe, Blum, and Pincus (1998) proposed that the decrease in communicative competence seen in patients with right hemisphere damage could, in part, be caused by a theory of mind impairment. These researchers compared 13 patients with right hemisphere damage to 20 control subjects on their ability to distinguish a joke from a lie. All subjects were presented with a series of eight, written lie stories, in which a character, thinking himself unobserved, tells a deliberate lie to conceal his actions. All subjects also received a series of eight, ironic joke stories, in which a character, realizing that his error has been observed, overtly lies in a joking fashion to conceal his embarrassment. The authors contended that attribution of a second order belief to the lie-teller, that is, realizing whether or not the lie-teller knows that his communication partner knows that he is lying, is crucial to distinguishing the lies from

20 jokes in these scenarios. Subjects stated whether the main character in each story was lying or joking and then answered a series of first and second order false belief questions, and comprehension questions, that followed each story. Six of 13 participants with right hemisphere damage failed first order false belief questions, all had difficulty with second order false belief questions, and all had consistent difficulty distinguishing a joke from a lie. All control subjects performed without difficulty. Winner and colleagues concluded that the poor theory of mind ability displayed by these individuals with right hemisphere damage was directly related to their impaired communicative competence. These authors reason that understanding what one person thinks that another person believes or knows (second order belief attribution) is fundamental to successful social interaction and communication. Unfortunately, although this clever study convincingly demonstrates a relationship between poor inferencing ability and poor interpretation of complex social situations, it fails to demonstrate that these individuals with right hemisphere damage have a specific theory of mind problem. Difficulty with making mental state inferences specifically is not clearly established because physical inference control questions were not included, and general cognitive abilities were not assessed. A general difficulty with drawing inferences in complex situations is sufficient to account for the poor performance of this right hemisphere-damaged group on theory of mind tasks, as well as their poor communicative competence. A theory of mind problem may indeed exist, but the failure to control for extraneous variables in this study makes this impossible to determine. Happe and colleagues (1999) have provided initial evidence for theory of mind impairment as at least a partial component of right hemisphere disorder. In contrast, some theorists maintain that the communication and social impairments seen in right hemisphere disorder stem from a fundamental disturbance of pragmatic language and holistic processing as historically thought, rather than from a basic difficulty in representing mental states. However, studies attempting to establish alternative, pragmatic or holistic bases for mental state inferencing deficits have been unconvincing. In one such study, Siegal, Carrington, and Radel (1996) attempted to demonstrate a pragmatic deficit in individuals with right hemisphere damage sufficient to account for

21 any apparent theory of mind difficulty. These authors theorized that the questions that traditionally follow first and second order false belief tasks require participants to follow unstated conversational implications, and that following these implications was the primary cause of theory of mind task difficulty. For example, a standard test question such as “Where will John look for his dog?” contains the unstated implication “Where will John look first for his dog?”. These authors predicted that the phrasing of false belief test questions explicitly (such as the second example above) would remove any performance difficulty for individuals with right hemisphere disorder on these false belief tasks. Seventeen individuals with right hemisphere damage were compared to a group of 11 individuals with left hemisphere damage. Approximately half of each group received unmodified, implicit false belief questions that required conversational implications to be followed, and the remaining individuals received questions with explicit phrasing that eliminated the need to understand conversational implications. One, first order false belief story was read aloud to each subject, followed by a first order, false belief question (either implicit or explicit, depending on group assignment), and a true-belief, control question to check for story comprehension and memory for story details. In addition, one true belief story was read aloud to each participant, and memory and comprehension control questions followed this story as well. As predicted by the authors, only the individuals with right hemisphere damage who were confronted with implicit, unmodified, traditional test questions had significant difficulty with these false belief tasks. Most of the left hemisphere-damaged participants had no difficulty, and most of the individuals with right hemisphere damage for whom the test questions were made explicit had no difficulty with the false belief questions or with the control questions. The authors concluded that any apparent theory of mind deficit exhibited by individuals with right hemisphere damage was actually caused by a pragmatic, holistic processing deficit that impairs the ability to follow complex, implied meanings. Although this study does demonstrate an absence of theory of mind impairment in a group of individuals with right hemisphere damage, it falls short of establishing any true amelioration of apparent theory of mind difficulty. Three of the 11 individuals with right hemisphere damage in the traditional, implicit question group had no difficulty with the false belief question. Of the remaining eight who had difficulty, seven also missed

22 the control, comprehension question. Therefore, this group does not exhibit even an apparent theory of mind difficulty, which requires that they miss only the false belief question while performing well on general cognitive, control questions. It is not surprising that this group fails to demonstrate a specific theory of mind deficit, because only three of the 11 group members suffered frontal lobe damage, while the remaining members exhibited either localized parietal or temporal lesions. Although the precise neuroanatomical location of theory of mind has not been determined, most experts locate theory of mind broadly within the frontal lobes. This anterior localization is the basis for the anterior/posterior distinction that underlies the theory of mind-based explanation of the social and communicative deficits common in right hemisphere disorder. In fact, this very model also postulates that a holistic processing impairment underlies the communicative difficulties of individuals with right-posterior damage. Therefore, the strong performance of the right hemisphere-damaged group who received modified, explicit, false belief questions is consistent with this anterior/posterior distinction model, because five of these six group members presented with posterior lesions, and would be expected to have pragmatic language difficulties. In a similar study, also with the purpose of establishing a holistic processing impairment as a cause for apparent theory of mind defecits, Surian and Siegal (2001) compared the performance of a group of 16 individuals with right hemisphere damage with a group of 16 with left hemisphere damage on traditional, first order false belief tasks. In addition, all participants were given visual aids for these false belief scenarios, to support visuo-spatial memory impairment. These authors reported that those individuals supported with visual aids had no difficulty on first order false belief tasks. This was true for both right and left hemisphere-damaged groups. Surian and Siegal claim that purported mental state attribution difficulties of individuals with right hemisphere disorder most likely stem from impairments in cognitive-general, visuo- spatial abilities. There are several problems inherent in this study, however, which compromise the validity of the authors’ claims. The majority of subjects who participated in this study (19 of 31) did not have anterior lesions. As argued previously, individuals with lesions localized to the posterior brain would not be expected to display any impairment

23 of theory of mind. It is not surprising that this group did not. The investigators also did not establish an initial theory of mind impairment before they compensated for this presumed impairment with visual aids. Therefore, they may have successfully compensated for a deficit that never existed at all. In addition, these authors restricted theory of mind testing to first order false belief tasks, and it is possible that higher-level theory of mind impairment is more typical of this population. Certainly the study by Happe and colleagues (1999), which has provided the best evidence for theory of mind impairment in the right hemisphere-damaged population employed second order false belief tasks, and it was on these second order tasks that individuals with right hemisphere damage had specific difficulty. Individuals with Dementia Individuals diagnosed with dementia have most recently been assessed for a possible underlying theory of mind deficit. Certain dementing illnesses such as Alzheimer’s disease and Fronto-temporal dementia (Pick’s disease) are characterized by deterioration of areas within the frontal lobes, the general brain region most widely implicated in theory of mind functioning (Fletcher et al., 1995; Stone et al., 1998). These also frequently result in emotional, pragmatic, and communicative deficits similar to those of autism, such as decreased insight, poor appreciation of the perspectives of others, lack of concern for others, and poor interpersonal communication (Gregory & Hodges, 1996). Cuerva, and colleagues assessed theory of mind ability in 34 individuals diagnosed with probable, mild Alzheimer’s type dementia (AD), and compared their performance to that of 10 normal control subjects (Cuerva, Kuzis, Tiberti, Dorrego & Starkstein, 2001). Participants read one, moderately complex, second order, false belief story, involving several characters with different beliefs, and answered five comprehension questions and one, second order false belief question. Participants also read 11, short, mental inferencing stories (Happe et al., 1994) that required interpretation of non-literal language such as irony and sarcasm. Following each of these non-literal inference stories, each participant was asked to explain the meaning of the non-literal statement in each story, and to answer a control, comprehension question. Unfortunately, only 14 of the 34 individuals with AD completed this series of short stories, and no

24 support for working memory was given during this testing. In addition to theory of mind testing, all participants completed two pragmatic skill tasks (comprehension of indirect requests, and comprehension of conversational implications), and a battery of neuropsychological tests assessing general cognitive and executive function skills. While control subjects performed well on all testing, and individuals in the AD group performed well on comprehension, control questions, only 12 of the 34 individuals in the AD group passed the second order false belief question. The investigators then compared this group of AD participants who passed this theory of mind question, to those AD participants who did not pass this second order false belief question, and who, therefore, exhibited theory of mind difficulty. Whereas the AD group as a whole had significant difficulty on the indirect requests measure of pragmatic skill, the theory of mind-impaired AD group scored significantly lower on the second pragmatic skills measure, comprehension of indirect requests, than did the sub-group of AD participants with intact theory of mind. In addition, those AD individuals with theory of mind impairment scored significantly lower on general cognition tests of auditory attention, abstract thinking, verbal memory, and verbal comprehension than did those AD individuals who did not exhibit theory of mind difficulty. Cuerva and colleagues claim that theory of mind deficits are clearly apparent in many individuals with mild dementia. Although the participants with AD also had impaired general cognitive functioning, these authors argue that such cognitive deficits cannot easily account for the observed theory of mind problems. In addition, because the group of individuals with both AD and poor theory of mind ability also scored significantly lower on one of two pragmatic skills tasks, these investigators hypothesize that a pragmatic language impairment is responsible for the observed theory of mind impairment. Although the finding that a significant number of individuals with AD exhibited a degree of theory of mind impairment is intriguing, these results should be interpreted cautiously. Because the majority of AD participants could not complete the bulk of the intended mental inferencing assessment, the reported theory of mind impairment in this group, and the comparisons drawn between those AD subjects with and without a theory of mind impairment, are based upon each participants answer to a single, second order false belief question. Making such claims based upon performance on one item is

25 problematic. In addition, general inferencing ability is not assessed or controlled for, so poor performance on the second order false belief question could be due to difficulty with drawing inferences in general, rather than to a specific mental inferencing problem. Further, the significant general cognitive impairments exhibited by those individuals with theory of mind impairment might easily account for failure on a single false belief question, particularly since the verbal processing and memory load were significant on this complex second order false belief task. Finally, the authors’ support for a pragmatic basis for theory of mind impairment, such as that advanced by Siegal (1996) is not easily justified by the results that they report. If the cognitive problems of poor verbal memory, poor verbal comprehension, and impaired abstract thinking are not sufficient to account for the theory of mind deficit in these AD individuals, then poor performance on one of two pragmatic language tasks hardly seems sufficient to explain this observed theory of mind difficulty. Lough, Gregory and Hodges (2001) presented a case of an individual diagnosed with fronto-temporal dementia of the frontal variant type (FTDfv), also known as Pick’s disease. This disorder is characterized by initial breakdown in social functioning with relatively spared general cognitive skills and executive functions, and is associated with specific degeneration within the frontal lobes (Gregory, 1999). The case subject presented with significantly compromised social and behavioral functioning, but with relatively intact intellectual capacity. This individual completed a battery of neuropsychological assessments, including extensive testing of various executive functions. The theory of mind assessment was also relatively thorough, and included four first order false belief tasks and four second order false belief tasks, 10 faux pas stories taken (Stone et al., 1998), and the Reading the Mind in the Eyes test (Baren-Cohen et al., 1997). The false belief tasks were depicted through a series of photographs with accompanying explanatory text, and each was followed by a false belief test question, a memory control question, and a comprehension control question. And following each faux pas story, the subject was asked to explain the faux pas situation, and also to answer a memory control question. This assessment revealed a profound theory of mind deficit, with minimal to no difficulty on standard tests of cognition and executive functioning. The case subject failed all the false belief questions while performing perfectly on all

26 comprehension questions, and was unable to detect or correctly explain any of the faux pas situations. Interestingly, this participant performed normally on the Reading the Mind in the Eyes test. The authors report that this theory of mind-specific deficit with almost completely preserved cognition and executive functioning was consistent with the social-behavioral problems combined with the spared reasoning and general intellectual capacity displayed by this individual in daily life. Lough and colleagues (2001) present these results as strong evidence for a specific theory of mind, separable from general cognitive functions, and also for the importance of theory of mind in normal social behavior and communication. In addition, these authors suggest a role for the orbital-frontal cortex and the amygdala in normal theory of mind functioning, as these areas were most notably atrophied in this case individual. Although these results from a single case study cannot be generally applied to a larger population, this case study does demonstrate a compelling disassociation between theory of mind and other cognitive and executive function skills, as the authors claim. The investigators effectively rule out cognitive-general or executive function impairment- based explanations for the demonstrated mental inferencing difficulty, both through extensive standardized cognitive assessment and through inclusion of appropriate control questions during theory of mind testing. The possible exception to this excellent experimental control may be general inferencing ability, which is neither overtly tested for nor controlled for during theory of mind assessment. It seems unlikely that an individual with an impairment in general inferencing profound enough to cause the observed overall failure on simple and complex theory of mind tasks would perform within normal limits on a battery of frontal lobe, executive function tasks; however, the possibility cannot be ruled out that a general inferencing difficulty might account for the observed mental inferencing difficulty. In addition, the subject’s high performance on the Reading the Mind in the Eyes task coincident with failure on all other theory of mind measures, may indicate that this assessment task is not sensitive to mental state inferencing impairment. More recently, Lough and colleagues have compared theory of mind ability in a group of 19 individuals with fronto-temporal dementia (FTDfv) to a group of 12 individuals with AD, and also to 16 normally functioning individuals (Gregory, Lough,

27 Stone, Erzinclioglu, Martin, Baren-Cohen, & Hodges, 2002). Individuals in the AD group were matched with members of the FTDfv group on performance in the Mini Mental State Examination, a screening instrument that broadly assesses degree of general cognitive impairment. Participants in the FTDfv group completed a battery of neuropsychological tests, and also a neuropsychiatric assessment of problem behaviors. A theory of mind assessment was completed by all participants, and was similar to that administered by Lough and colleagues (2001) in the study discussed above, with the addition of a physical inference control question following each of the eight false belief tasks. The FTDfv group showed a significant, specific theory of mind impairment an all assessment tasks, relative to normal controls, and to their own performance on control questions and general cognitive and executive function tasks. The theory of mind difficulty of this group increased as the assessment tasks placed increasingly more demand on mental state inferencing ability, and analysis revealed high internal consistency between first order, second order, and faux pas tasks. However, scores in this group on the Reading the Mind in the Eyes task were not associated with other theory of mind scores, suggesting that this test may not be a valid measure of mental state inferencing ability. The AD group performed significantly worse than normal controls on the second order false belief tasks, while passing all control questions. However, the performance of this group on first order questions, faux pas stories and the Reading the Mind in the Eyes task was not significantly below that of normal control subjects, so this group displayed an inconsistent, but selective difficulty with theory of mind tasks. Because this AD group did not complete a general cognitive assessment, comparisons between theory of mind performance and general cognitive impairment could not be made. These authors interpret these results as further evidence for a theory of mind function that is independent from other cognitive general and executive function skills. They claim that a pervasive theory of mind deficit exists in individuals with FTDfv, but report no evidence of theory of mind impairment in the AD group. Further, they report that the most consistent, significant area of damage in the FTDfv group was in the ventral-medial frontal cortex, and suggest that this region may be important in theory of mind function.

28 This is a well-conducted, well-controlled investigation, which presents strong evidence for the disassociation of theory of mind from executive skills and cognitive general functions that other investigators have suggested may underlie mental state inferencing ability. The claim for lack of evidence of theory of mind problems in the AD group, however, may be a skewed interpretation of these results. The authors suggest that the poor performance of the AD group on second order theory of mind tasks may be explained by the high demand of these tasks on working memory and . This explanation seems unlikely, however, because stimuli were left in place throughout testing specifically to control for memory impairment, and because this group had no difficulty with the memory control questions for this task. In fact, this group displayed a well-controlled, specific, theory of mind impairment on this traditional mental state inferencing assessment task, as it has been historically defined and interpreted in the literature. Although this impairment is not as extensive or consistent as that demonstrated by the FTDfv group, it remains good evidence for a specific theory of mind impairment. The authors contend that the lack of difficulty of the AD group on the higher level, faux pas task indicates intact theory of mind, since this test is the most sensitive of those included in this study. Although the faux pas task is the most difficult of the theory of mind tasks included in this study, this does not mean that it is the most sensitive to theory of mind impairment, or the most valid measure of theory of mind ability. False belief scenarios are the most theoretically grounded, and the most commonly used assessment method. They are less complex than higher-level tasks such as the faux pas task, and make fewer demands on executive function and cognitive general skills. Therefore false belief tasks are arguably less confounded, more selective measures of theory of mind ability. Poor performance on a false belief task should provide evidence for a more extensive, fundamental theory of mind deficit than would poor performance on higher-level tasks. At the least, the performance of this AD group should be considered inconsistent evidence for a specific theory of mind impairment, to be confirmed or denied by further testing.

29 Summary of Evidence for Theory of Mind Impairment

Investigations of individuals with dementia have provided the strongest evidence for a domain specific, possibly modular, theory of mind. The impressive research of Lough and colleagues (2001, 2002) suggests that some individuals with fronto-temporal dementia exhibit a selective difficulty with theory of mind, and that this deficit may cause social-communicative impairment. These investigators also have presented inconsistent evidence of a specific theory of mind deficit in individuals with Alzheimer’s type dementia, although further research is needed to differentiate mental state attribution difficulty from other cognitive impairments in this population. Happe and colleagues (1999) have presented similarly well-documented evidence for a theory of mind impairment in individuals with right hemisphere disorder due to stroke, and consequently for the existence of a functionally distinct theory of mind. This single study suggests that the social and communicative difficulties incurred by this population may at least in part be due to an underlying impairment in attributing mental states to others. Unfortunately, the other currently reviewed studies conducted with this population were not experimentally sound enough to support their similar claims. However, investigations attempting to refute the findings of Happe et al, (1999) by demonstrating a more pragmatic or holistic processing explanation for theory of mind impairments in individuals with right hemisphere disorder, have been likewise flawed, and unconvincing. Studies of individuals with acquired frontal lobe damage, both diffuse and local, also have supplied initial support for a domain-specific theory of mind, and for a theory of mind-based explanation of the social and communicative impairments exhibited by this population. Rowe and colleagues (2001) effectively demonstrated a dissociation of theory of mind ability from other cognitive functions in this population. Stone et al., (1998) also reported evidence of this disassociation, although theory of mind impairment was based on the less established, high-level faux pas measure in this study. The case study evidence presented by Happe et al. (2001) also indicates a potential theory of mind problem, but falls short of distinguishing this impairment from other cognitive deficits exhibited by the subject.

30 Most of the investigations reviewed in this paper that report a specific theory of mind impairment also attempt to identify the damaged brain areas that might account for the observed mental inferencing problem. It is perhaps most beneficial, however, to review only those claims for localization that are supported by well controlled research which clearly establishes a specific theory of mind deficit, well distinguished from other cognitive impairments. Lough and colleagues (2001; 2002) identified bilateral damage to the ventral-medial and orbital-frontal regions of the frontal lobe, and also to the amygdala, as contributing to theory of mind impairment. Stone et al. (1998) likewise implicate the orbital-frontal cortices in attribution of mental states. Happe and colleagues (1999) localized theory of mind generally within the right hemisphere, and the majority of their subjects presented with right-anterior damage. And Rowe et al. (2001) also presented evidence for right-frontal localization of theory of mind. Functional Imaging Evidence for Localization of Theory of Mind In addition to this preliminary, lesion-based evidence for different candidate theory of mind structures, investigators have performed functional imaging studies to establish brain regions specifically activated during theory of mind tasks. A handful of imaging studies have been performed to date, and these have primarily compared areas of activation in normal subjects during mental versus non-mental tasks. Perhaps the most striking characteristic of this body of work is the disparity in theory of mind tasks employed across studies. Also striking, and likely a consequence of this task variation, is the lack of agreement among these studies on the specific structures active during mental inferencing tasks. None of these imaging studies conducted with normal subjects agree on the localization of potential theory of mind neural structures. However, some overlap of identified structures does exist. The most commonly activated brain region during theory of mind tasks was the left medial prefrontal cortex, generally identified as Brodmann’s area 8 by investigators. Fletcher and colleagues (1995) employed high-level, non-literal short stories from Happe et al., (1994), and reported specific activation of the left medial prefrontal cortex, along with specific activation of the posterior cingulate cortex. Gallagher and colleagues, in a rare attempt at continuity, also used the short stories employed by Fletcher and colleagues (1995), in addition to a series of mental inferencing

31 cartoon strips. These investigators reported that only the medial prefrontal cortex was uniquely activated during both verbal and visual mental tasks, however this activation occurred in both the left and right hemispheres (Gallagher, Happe, Brunswick, Fletcher, Frith & Frith, 2000). Goel and colleagues (1995) also reported localized activation of the left medial prefrontal area during an object-knowledge task that required making mental state attributions. However, the left temporal cortex also was uniquely activated by this non-traditional mental inferencing task. And Baron-Cohen and colleagues reported left medial prefrontal cortex activation during the Reading the Mind in the Eyes task. However this was coincident with similar activation of several other areas: the left dorsolateral prefrontal cortex, the left prefrontal supplemental motor area, the left and right temporal-parietal areas, the left and right insular cortices, and the left amygdala, hippocampus, and striatum (Baron-Cohen, Ring, Wheelwright, Bullmore, Brammer, Simmons, & Williams, 1999). Similar imaging of individuals with high-level autism and impaired theory of mind was also performed, and activation of the left amygdala was notably absent, causing the authors to speculate that the amygdala may be particularly important to normal theory of mind. Although a large disparity exists among these studies, they have at least identified one common structure, the left medial prefrontal cortex, which was uniquely active during mental state inferencing tasks. However, not all imaging studies agree on even this. Baren-Cohen and colleagues (1994) found only right orbital-frontal cortical activity during a task requiring identification of mental and non-mental words. And Brunet and colleagues employed a visual, mental state cartoon task, and reported specific recruitment of the right medial prefrontal cortex, the right inferior prefrontal cortex, the bilateral temporal lobes, and the left cerebellum (Brunet, Sarfati, Hardy-Bayle, & Decety, 2000). In this, Brunet and colleagues were partially consistent with Gallagher and colleagues (2000) who reported right medial prefrontal activity, and with Baron-Cohen (1999) and Goel (1995) in their finding of temporal lobe activity during mentalizing tasks. Together, these investigations identify a myriad of active brain regions, both frontal and non-frontal, that are uniquely activated by theory of mind tasks, with very little agreement across studies. Although the logistics of functional brain imaging necessitate experimental creativity, particularly because of the constraints placed on

32 movement-based responding, the large variation in experimental tasks makes it difficult to interpret these disparate findings. In fact, it is not clear that all of these investigations are measuring specific theory of mind activation. Baron-Cohen and colleagues employ a mental lexicon task (1994) and a Reading the Mind in the Eyes task (1999), both of which possess questionable validity as tests of mental state attribution. And Goel and colleagues (1995) employ a novel task involving mental state attribution during object use, which has not been established or replicated as a theory of mind measure. Researchers have suggested that theory of mind may be supported by a network of several, discrete, neural structures, and that some or all of these component structures may specialize in a particular aspect of theory of mind (Baron-Cohen et al., 1995). If this is the case, then it is possible that task differences might elicit corresponding differences in activity patterns across a network of structures, all of which contribute to normal theory of mind. This is a plausible explanation for the variation in activity patterns that has corresponded with theory of mind task variation, and this hypothesis has the potential to validate and unify these apparently inconsistent results. However, a series of experiments that systematically varies task demands and carefully correlates task demands with activated brain regions must be carried out before this theoretical explanation can become more than mere conjecture. There is a small degree of correspondence between the brain structures activated during functional imaging studies, and the brain regions implicated in theory of mind impairment in investigations of individuals with acquired neurological damage. In their investigations of individuals with right hemisphere disorder, Happe and colleagues (1999) and Rowe and colleagues (2001) generally implicate the right frontal lobes in theory of mind, and this general, right-hemisphere basis is supported by the functional imaging results of Brunet (2000) and Baron-Cohen (1994). Stone and colleagues primarily identified bilateral orbital-frontal damage in individuals with theory of mind impairment due to frontal lobe injury, and this is supported by only one of these imaging studies, that of Baron-Cohen and colleagues (1994). In addition, Lough (2001) and Gregory (2002) agreed with Baren-Cohen (1994; 1999) in their identification of orbital frontal cortex and the amygdala as important to mental inferencing (1994; 1999).

33 Contributions of Theory of Mind Investigations of Neurogenic Populations Preliminary evidence for a specific theory of mind impairment, distinct from general cognitive and executive function difficulties, has been presented for individuals with frontal lobe damage, individuals with right hemisphere disorder, and individuals with fronto-temporal dementia. Evidence for a specific theory of mind impairment in individuals with Alzheimer’s type dementia has been inconsistent. These studies have suggested a causal link between theory of mind impairment and the social- communicative difficulties common to these populations. If a fundamental difficulty with theory of mind does underlie such social and behavioral problems, then a new approach to treating these disordered individuals may be warranted. Much more research must be done, however, before such social-communicative impairments can be attributed, even in part, to a specific difficulty with theory of mind in these populations. Implications for models of theory of mind. Studies such as those of Lough (2001), Gregory (2002) and Rowe (2001) that carefully control for alternative cognitive explanations, have demonstrated a disassociation between theory of mind and other general cognitive skills and executive functions in individuals with acquired neurogenic impairment. This evidence for a specific theory of mind impairment is most consistent with the modular view of theory of mind, which posits a functionally and neuroanatomically distinct theory of mind that can be selectively impaired. Neurological investigations such as these, however, cannot address the innateness claim for this theory of mind module that is made by some modular theorists. This evidence from neurogenic populations neither supports nor specifically refutes the simulation theory perspective, which claims that general perspective taking ability underlies theory of mind. These investigations neither test nor control for general perspective taking skill, possibly because visual perspective taking is believed to be intact in autistic individuals who exhibit impaired theory of mind (Baron-Cohen et al., 1993). However, if the previously mentioned study by Langdon and Coltheart (2001) is replicated, theory of mind investigations may need to rule out a visual perspective taking impairment more rigorously in order to establish a true disassociation between theory of mind and general perspective taking. The theory-theory model of theory of mind, which predicts that impairment of theory of mind should coincide with impairment of general inferencing

34 ability, is not supported by this evidence. General inferencing ability has remained relatively intact in those individuals with acquired neurological damage who exhibit a significant theory of mind impairment. In addition, the significant disassociation between theory of mind and executive functions presented by Lough (2111), Gregory (2002), and Rowe (2001) contradict the contention of some theorists that a separate theory of mind ability does not exist, and that executive function impairment is sufficient to account for all theory of mind difficulties (Ozonoff et al., 1991; Hughes and Russel, 1994). The consistent failure on even simple theory of mind tasks with relatively normal executive function skills that is displayed by some individuals with neuroloci impairment is inconsistent with this executive function-based explanation. Implications for neural localization of theory of mind. Investigations of populations with acquired neurogenic disorders combined with brain imaging studies of normally functioning individuals have been generally localized theory of mind at least partially within prefrontal cortex. However, these studies are inconsistent in their identification of specific prefrontal regions that may support theory of mind. Although the medial prefrontal cortex was activated frequently across studies, these studies disagree on the laterality of this activation. Further, several additional prefrontal areas, along with several non-frontal regions have also been implicated by these various investigations. These inconsistent and often contradictory results lend little anatomical support to notion of a domain specific theory of mind, even to that of one composed of a complex, interconnected network of neural structures. Suggestions for future research. In order to make meaningful gains, future investigations must carefully and consistently control for possible alternative cognitive impairments that might reasonably account for apparent mental inferencing difficulty. In addition, investigations must employ tasks that validly assess theory of mind, that is, the specific ability to attribute mental states to others, and to use this knowledge to interpret actions and intentions. Novel assessment tools, such as the Reading the Mind in the Eyes test (Baron-Cohen et al., 1997) and the mental versus non-mental word lexicon task (Baron-Cohen, 1994), have been validated as theory of mind tasks based on the difficulty they pose to persons with autism (Baron-Cohen et al, 1997). Although a basic theory of mind deficit has been invoked as a core deficit in autism, this does not mean that any task

35 on which autistic individuals have difficulty is necessarily a valid test of theory of mind. In addition, it is important that researchers identify any general cognitive or executive components contained in theory of mind tasks, particularly those that assess high-level mental state attribution. If the component skill requirements of these tests are understood, then researchers can accurately interpret the relative contribution of theory of mind impairment to an individuals’ overall performance. Further, future research needs consistently employ similar theory of mind tasks across different populations, in both impairment-based and neuroimaging studies. Expansion of theory of mind assessment through development of innovative theory of mind tasks is commendable. However, new assessment tasks should be theoretically valid as specific tests of mental state inferencing, and should be used in conjunction with traditionally established assessment tasks. New research should also focus specifically on localizing a network of structures that support theory of mind. Because the majority of evidence against a discrete theory of mind ability arises from correlations between executive function and theory of mind abilities, localization of theory of mind in proximity to executive function structures might account for a greater part of the evidence against a theory of mind. The best case that researchers could put forth in defense of a theory of mind is the distinct anatomical localization of theory of mind component structures. If such structures could be identified, their existence would help establish theory of mind as a distinct cognitive function. And if these structures were located near executive function structures, as seems likely, then the correlations between executive functions and theory of mind would be explained. In addition, the localization of component structures that support theory of mind could help investigators determine the extent to which a theory of mind impairment might account for the social, pragmatic and conversational difficulties seen in various populations with acquired neurogenic disorders.

36

CHAPTER 2 INTRODUCTION

Theory of Mind

Theory of mind is the ability to attribute mental states, such as beliefs, desires and intentions, both to oneself, and to other individuals (Premack & Woodruf, 1976). Fundamental to this social skill is the appreciation that other people may be acting on beliefs that are different from one’s own. An intact theory of mind may enable the mental perspective-taking necessary to comprehend and predict the complex nuances of social communication (Baron-Cohen, Leslie, & Firth, 1985; Winner, Brownell, Happe, Blum, & Pincus, 1998). Many investigators assert that theory of mind is a cognitive-specific, modular skill that is functionally, and possibly anatomically, distinct from other high-level cognitive skills (Baron-Cohen et al., 1985; Leslie & Thaiss, 1992). In support of this view, theorists have demonstrated that individuals with autism commonly exhibit a selective impairment of theory of mind, while high-level linguistic abilities and executive functions are relatively spared (Baron-Cohen et al., 1985; Frith & Frith, 1999). In addition, research has shown that theory of mind can be selectively spared relative to general cognitive functions in individuals with Down’s syndrome and William’s syndrome (Karmiloff-Smith, Kilma, Bellugi, Grant, & Baron-Cohen, 1995). This double disassociation between theory of mind ability and cognitive-general functions strongly suggests that theory of mind may indeed be a distinct, cognitive ability, independent from other cognitive skills. Evidence that theory of mind skills develop in an age-dependent sequence that is separable from cultural and general intelligence factors also support theory of mind modularity (Avis & Harris, 1991; Wimmer & Perner, 1983). Although much evidence in favor of a distinct theory of mind ability has been presented, some theorists contend that a distinct theory of mind ability does not exist.

37 Instead, these researchers believe that executive functions are sufficient to perform the mental inferencing skills attributed to theory of mind, without the invocation of any specialized theory of mind skill (Hughes, Russel, & Robbins, 1994; Ozonoff, Pennington, & Rogers, 1991). These theorists who reject a theory of mind construct argue that the tasks traditionally used to assess theory of mind ability primarily test executive function component skills; they specifically identify deficits in the executive functions of set- shifting and response inhibition as causes of apparent theory of mind impairments. For example, an individual might either fail to inhibit a response based upon his own beliefs, or fail to shift a set mode of responding, and so fail to display actually intact knowledge of a mental state perspective held by another person (Hughes et al., 1994). Tests of false belief are the most established method of assessing theory of mind ability (Dennet, 1978). First order, false belief tests establish whether an individual can attribute a false belief to a story character. For example, an individual might observe a character, Sara, moving a cookie from it’s hiding place once a second character, Jim, has left the room. The individual completing this false belief task would display intact theory of mind ability if he predicted that Jim, upon re-entering the room, would look first for the cookie in its old location, rather than in its new hiding place. In order to make this correct prediction, the individual must be able to look past, or inhibit, his own knowledge of reality, and appreciate instead the false belief held by another person (Wimmer & Perner, 1983). Second order, false belief tests are more complex, and require an individual to attribute a false belief about a belief. For example, if unbeknownst to Sara (but known to the test taker) Jim peeked back into the room and observed Sara changing the hiding place of the cookie, Sara would then falsely believe that Jim believes the cookie is still hidden in its original location. Sara would hold a false belief about Jim’s belief. Second order, false belief tasks assess the test taker’s ability to correctly attribute this second order false belief to Sara. Children generally pass first order, false belief tests at age three and not before, and generally pass second order, false belief tasks at age six or seven (Perner & Wimmer, 1985). It is common for adults with autism to fail first and second order, false belief tasks while passing similar tests that involve representing false beliefs about the physical

38 world and making inferences about the physical world, rather than about the mental states of other people (Leslie & Thaiss, 1992; Zaitchile, 1990). Most theory of mind investigations, regardless of the type(s) of theory of mind tasks employed, include additional tasks and/or questions that assess cognitive-general abilities such as working memory and general inferencing ability. Comprehension questions are also frequently included to determine whether participants understand task stimuli. In addition, a few investigators have provided written or pictorial stimuli during testing to decrease task demands on working memory. Study participants who display a theory of mind impairment that is dissociable from impairments in other cognitive domains such as memory or general inferencing can be most confidently diagnosed with a specific difficulty in making mental state attributions. And theory of mind impairments that are dissociable from other cognitive deficits provide evidence for the existence of a specific, cognitive module for theory of mind ability. Impairment of such a theory of mind module may greatly impact social skills and communication abilities. Theory of mind impairment was initially invoked as the core deficit in autism, and deficits common to autism, such as poor social judgment, paucity of social interaction, emotional indifference, poor conversational pragmatic skills, and poor comprehension of abstract language, have frequently been ascribed to underlying theory of mind difficulties (Baron-Cohen et al., 1985; Baron-Cohen & Ring, 1994; Wimmer & Perner, 1983). Intact theory of mind also has been proposed as a critical component for other high-level communication skills, such as complex discourse comprehension, appreciation of humor, and comprehension of nuances of communication such as irony and sarcasm (Baron-Cohen & Ring, 1994). Theory of Mind in Dementia Relatively recently, investigators have expanded investigations of theory of mind impairment to adults with acquired, neurogenic disorders. Several different populations have been identified who exhibit deficits similar to those observed in high level, autistic individuals. Individuals with right hemisphere damage frequently have difficulties with social and pragmatic aspects of communication, and investigators have presented initial evidence that a theory of mind impairment may be at least a partial cause of social- communicative difficulties in this population (Happe, Brownell, & Wimmer, 1999).

39 Adults with both diffuse and focal frontal lobe damage can exhibit specific mental state inferencing difficulty that is dissociable from high-level executive function impairment (Rowe, Bullock, & Polkey, 2001; Stone, Baron-Cohen, & Knight, 1998). Initial evidence also has been presented for an underlying theory of mind impairment in individuals with frontal variant Fronto Temporal Dementia (FTDfv), also known as Pick’s disease. This disorder is characterized by deterioration of areas within the frontal lobes, the brain region most widely implicated in theory of mind functioning (Fletcher, Happe, Frith, Baker, Dolan, & Frackowiak, 1995; Stone et al., 1998). FTDfv is characterized by emotional, pragmatic, and communicative deficits similar to those of autism, such as decreased insight, poor appreciation of the perspectives of others, lack of concern for others, and poor interpersonal communication (Gregory & Hodges, 1996). Gregory and colleagues recently demonstrated a specific theory of mind impairment in individuals with FTDfv (Gregory, Lough, Stone, Erzinclioglu, Martin, Baren-Cohen, & Hodges, 2002). Investigators also have presented compelling evidence for a specific theory of mind deficit, in the absence of significant memory difficulty or executive function impairment, in an in-depth case study of an individual diagnosed with FTDfv (Lough, Gregory, & Hodges, 2001). Evidence for a specific theory of mind impairment in individuals with a diagnosis of probable Alzheimer’s type dementia (AD) has been less convincing. AD has been associated historically with an initial presentation of memory difficulties, and with associated degeneration of temporal lobe and limbic lobe areas (Arnold, Hyman, Flory, Damasio, & Van Hoesen, 1991). However, in addition to the pervasive and progressive disorder of memory that characterizes AD, frontal lobe-type abnormalities in decision making, executive control, inhibition, and personality have been documented in this population (Van Hosen & Damasio, 1987). Because of this additional frontal profile of cognitive and behavioral impairment, involvement of frontal association areas has been postulated in AD (Cuerva, Sabe, Kuzis, Tiberti, Dorrego, & Starkstein, 2001). Further, Van Hosen, Parvizi, and Chu (2000) have demonstrated marked deterioration of the orbitofrontal cortex in AD, one of the areas of the frontal cortex that recently has been associated with theory of mind functioning (Baron-Cohen & Ring, 1994). It is therefore reasonable to hypothesize that a specific theory of mind impairment may be present in

40 individuals with AD. It is also possible that such a specific difficulty in making mental state inferences, and in using inferences about the mental states of others to appropriately guide communication and predict behavior, could be partially responsible for the socio- communicative deficits common to AD (Cuerva et al., 2001). An initial indication that a theory of mind impairment may be present in individuals with AD has been provided in the previously mentioned study by Gregory and colleagues (2002) that focused on theory of mind impairment in individuals with FTDfv. Although these authors focused their attention on the pervasive theory of mind impairment evidenced by their FTDfv participants, their results also indicated a specific, significant, second order theory of mind impairment in their AD control group. In addition, an unpublished master’s thesis has indicated that a mental state inferencing deficit may exist in individuals with AD, although a claim for specificity of theory of mind impairment, as opposed to executive function impairment, was not made (Lowe, 2001). Only one investigation in the published literature has specifically investigated theory of mind ability in the AD population. Cuerva and colleagues (2001) assessed theory of mind ability in 34 individuals diagnosed with probable, mild AD, and compared their performance to that of 10 control subjects. Study participants read one, second order, false belief story, answered one, second order false belief question, and read and responded to questions about 11, short, high-level mental inferencing stories that required interpretation of non-literal language, such as irony and sarcasm (Happe, 1994). Unfortunately, only 14 of the 34 individuals with AD completed this series of 11, high level short stories. The authors reported that while control subjects performed well on all testing, and individuals in the AD group performed well on comprehension control questions, only 12 of the 34 individuals in the AD group passed the second order, false belief question. In addition, those AD individuals with theory of mind impairment scored significantly below those AD participants without a theory of mind impairment on tests of auditory attention, abstract thinking, verbal memory, and verbal comprehension. Based on these results, Cuerva and colleagues claimed that theory of mind deficits are clearly apparent in many individuals with mild dementia. Although the participants with

41 AD also exhibited impaired general cognitive functioning, these authors argue that general cognitive deficits did not account for the observed theory of mind deficits. Although the finding that a significant number of individuals with AD exhibited a degree of theory of mind impairment is intriguing, these results should be interpreted cautiously. Because the majority of AD participants did not complete the bulk of the intended theory of mind assessment, the reported theory of mind impairment of this group is based upon each participant’s answer to a single, second order, false belief question. Identifying a specific cognitive deficit based upon performance on only one test question is problematic. In addition, general inferencing ability was not assessed or controlled, so poor performance on the second order, false belief question could have been due to difficulty with drawing inferences in general, rather than to a specific mental inferencing problem. Further, the investigators did not provide support for working memory during theory of mind tasks, nor did they include control questions for memory of story details, and so the possibility remains that the observed theory of mind difficulty of the AD group may have been due to the marked memory impairment that typifies this population. Finally, executive function abilities of AD participants in this study were not assessed, and, therefore, the possibility that executive function difficulties may have given rise to apparent theory of mind difficulty could not be addressed. It is apparent that further investigations that control for general inferencing abilities are needed to explore the possibility of a specific theory of mind impairment in the AD population. It is also important that studies assess the executive functions of set shifting and response inhibition associated with theory of mind testing, as impairment of these abilities has been proposed as an alternative explanation for apparent mental state inferencing difficulty. In addition, it is important that a possible contribution of memory impairment to theory of mind difficulty be investigated. Because the AD population is characterized by general cognitive, executive function, and memory impairments, the parsing out of a specific theory of mind deficit presents a methodological challenge. However, to the extent that it is possible, such delineation is necessary to establish whether or not any apparent mental state inferencing difficulty within this population is primarily attributable to a specific theory of mind impairment, rather than to more general cognitive deficits. If a specific theory of mind impairment is present in the AD

42 population, a shift toward a theory of mind or mental state inferencing-based treatment of the social-communicative impairments exhibited by this population may be warranted.

Purpose

The purpose of the present study was to explore the possibility that individuals with AD might exhibit a specific impairment of theory of mind on traditional false belief tests. Individuals were given a series of theory of mind tasks, controlled with general comprehension, physical inference, and memory questions. They completed these tasks in an unsupported memory condition and also in a supported memory condition to explore any differences in theory of mind performance that might emerge when support for working memory was given. The performance of AD participants on these false belief tasks was compared to the performance of a group of elderly, control participants, who completed the same false belief scenarios. In addition, this investigation described possible relations between theory of mind difficulty and impaired performance on psychometric tests of general cognition, memory, and executive functions. Several neuropsychological instruments were completed by AD participants to control for and assess possible contributions of deficits in these cognitive domains to any apparent theory of mind difficulty, and to explore relations between such cognitive impairments and theory of mind difficulty. The experimental questions addressed by this investigation were:

1. Do the AD participants in this investigation exhibit specific theory of mind difficulty as measured by first order, false belief tasks and second order, false belief tasks compared to the performance of control participants? 2. Does the provision of support for working memory improve theory of mind test performance of AD participants, as measured by overall error scores and specific theory of mind impairment scores, compared to theory of mind task performance of AD participants without support for working memory? 3. In the case of inconclusive theory of mind trials which include concurrent errors on false belief test questions and control questions, is one type of control question

43 missed most commonly? If so, is there a relation between the type of control question error that interferes with theory of mind impairment determination and impairment of general cognitive functioning, memory, and/or executive functions as measured by psychometric instruments? 4. Does the degree of theory of mind impairment of individuals with AD in the present investigation correspond with the degree of impairment in general cognition, memory, and/or executive functions as measured by psychometric instruments?

It was hypothesized that AD participants would perform poorly on both unsupported and supported theory of mind tasks as compared to control participants, as measured by their total error scores. A specific theory of mind impairment was considered more likely to appear in second order, false belief testing than on first order testing based upon theory of mind difficulties evidenced by higher level AD participants in previous studies (Cureva et al., 2001; Gregory et al., 2002). It was also predicted that any specific theory of mind difficulty demonstrated in the unsupported memory condition might be partially or wholly alleviated by the provision of memory support. This would suggest that apparent theory of mind difficulties might be attributable, at least in part, to the pervasive memory deterioration that characterizes the AD population. In addition, it was predicted that total error scores would be lower on theory of mind testing in the supported condition as compared to unsupported condition performances. For the analysis of inconclusive theory of mind trials, it was hypothesized that prevalence of a specific type of control question error (comprehension, memory or physical inference) might correlate with deficits in that cognitive skill as measured by psychometric instruments. It was also predicted that AD participant scores on tests of general cognition and memory might correlate with theory of mind impairment scores and overall error scores, particularly in unsupported memory testing.

44

CHAPTER 3 METHOD

Participants

Alzheimer Participants Candidates for the AD participant group were recruited from long term care residences, adult day care facilities and Alzheimer support groups in the Florida panhandle area. Staff working in these groups and facilities was approached about possible recruitment of their members, and only those families and residents who indicated willingness to the staff were then approached by the primary investigator. Written consent was obtained from both primary caregivers and potential AD participants prior to study participation. AD candidates recruited for this investigation were native, fluent English speakers. All potential participants were screened through medical chart review and caregiver interview for past or present confounding neurological illness, past or present psychiatric illness, developmental or learning disabilities, or any severe medical illness that could impair cognitive function. Only those individuals who met these primary inclusion criteria were further profiled for possible inclusion in the present investigation AD candidates were carefully profiled prior to participation in the present investigation through a pre-assessment battery of screenings and neurocognitive tests. Because AD participants were recruited from community settings where NINCDS- ADRDA criteria for diagnosis of probable AD were not frequently employed, the primary investigator established AD profiling criteria for selection of AD participants to ensure selection of a homogeneous AD experimental group. All AD group participants were profiled by two instruments, the Dementia Rating Scale, Second Edition (DRS-2; Jurica, Leitten, & Mattis, 2001) and the Rey Complex Figure Test (RCF; Rey, 1941)

45 which, taken together, have been shown to differentiate Alzheimer’s type dementia from other dementias, including frontal dementias, with 80% to 82% accuracy (Hodges, Garrard, Perry, Patterson, Ward, Bak, & Gregory, 1999; Salmon, Kwo-on Yuen, Heindel, & Butters, 1989). These two AD profiling instruments were completed by all candidates, even those who already carried a specific, NINCDS-ADRDA based, probable AD diagnoses, because currently accepted NINCDS-ADRDA diagnostic criteria have been shown to distinguish AD from frontal dementias with only 23% accuracy (Varma, Snowdon, Lloyd, Talbot, Mann, & Neary, 1999). In addition to the two AD profiling instruments, the Pre-assessment battery included a functional hearing screening, a brief oral reading and reading comprehension screening, and completion of the Mini Mental State Examination (MMSE), which was used to establish a mild to moderate level of general cognitive functioning. Dementia Rating Scale-2 (DRS-2; Jurica, Leitten, & Mattis, 2001). This assessment provides an overall index of general cognitive functioning and also indicates degree of impairment across several cognitive domains. This instrument is composed of five subscales: Attention, Initiation and Perseveration, Construction, Conceptualization, and Memory. The total possible raw score for all five subtests is 144, and the cutoff raw score for mild impairment is 123. Total DRS-2 scores and scores for each subtest are converted to scaled scores with a mean of 10, and impairment cutoff of 6. The DRS-2 also provides an age and education adjusted scaled score (AMESS) for overall DRS-2 performance. Pattern analysis of the DRS-2 performance profiles provides a characteristic impairment pattern for AD. This pattern has been shown to differentiate AD from dementias associated with Parkinson’s disease and Huntington’s chorea based upon differences in performance among cognitive dimensions (Salmon et al., 1989). In accordance with this established DRS-2, AD-typical profile, AD candidates were required to obtain Memory subscale scores that were at least 15% lower than scores on the Attention, Initiation, Construction, and Conceptualization subscales to meet AD profile, inclusion criterea. In addition, within the Memory subscale, recall item performances for AD specific profiles were required to be at least 25% lower than verbal and figural recognition performances.

46 Rey Complex Figure Test (RCF; Rey, 1941). AD group candidates also completed this measure of episodic memory and working memory, which also has been demonstrated to provide an AD-typical performance pattern. On the RCF, the participant copies a complex figure as accurately as possible. The participant then attempts to reproduce the figure from memory after a 3 minute delay, and again following a 45 minute delay. The maximum score on each memory trial is 36: two points were given for each of 18 identified figure subcomponents. The RCF has been shown to be sensitive to performance differences between normal individuals and individuals with probable AD (Berry, Allen, & Schmitt, 1991). It has recently been shown to result in a distinctive performance profile that distinguishes mild to moderate AD from both FTDfv and Semantic dementia (temporal variant FTD) with 80% to 82% identification accuracy (Hodges et al., 1999). The frontal dementias are difficult to distinguish from AD, and currently accepted NINCDS-ADRDA diagnostic criteria have been shown to distinguish AD from FTD variants with only 23% accuracy (Varma, Snowdon, Lloyd, Talbot, Mann, & Neary, 1999). Hodges and colleagues have demonstrated that individuals with AD consistently perform significantly worse on the 45 minute delayed recall of the RCF than do individuals with FTD, and they describe AD-typical scores of 4 or below on this 45 minute recall task. Accordingly, AD group candidates were required to score no more that 4 of a possible 36 points on the 45 minute recall portion of the RCF to meet pre-assessment inclusion criteria for the present investigation. Mini Mental State Examination (MMSE; Folstein, Folstein, & McHugh, 1975). To establish general cognitive abilities sufficient for the present investigation, each AD group candidate completed the MMSE, a screening instrument that measures global cognitive ability. Only those individuals scoring in the mild to mild-moderate impairment range, defined as 17 to 23 out of 30, were included in this investigation. This minimum score criterion for inclusion was based upon a report from Cuerva and colleagues (2001), who found that AD participants with MMSE scores of 15 or below provided unreliable responses during theory of mind assessments. Reading Screening. Potential AD participants completed a brief oral reading screening comprised of a single, brief paragraph written by the investigator, similar to

47 theory of mind test scenarios, followed by two reading comprehension questions, also similar to questions in theory of mind testing, to ascertain that they possessed the minimum reading ability necessary to comprehend the theory of mind assessment stories included in the present investigation. The text of this paragraph was at a fifth grade reading level (5.0 Flesch-Kincaide Grade Reading Level; Flesch, Fishburne, Rogers, & Chissom, 1975), and was representative of the stories that comprised the theory of mind assessment, which ranged from Flesch-Kincaide Grade Reading Levels of 3.6 to 5.3. Candidates were also asked to read aloud and answer two comprehension questions that followed this story, which were similar to the comprehension control questions included in theory of mind assessment. During this brief screening the story text was not left in place for the participants to refer to when answering questions. Only those individuals who were able to read this screening story aloud at an independent, fifth grade level, and answer at least one of the two comprehension questions correctly, were included in the study. The grade level of oral reading performance was determined using the Graded Reading Passages Test scoring system presented in the Steiglitz Informal Reading Inventory (Stieglitz, 2002). Cutoff error scores are at three errors or less for reading at an independent level. The short screening story, comprehension questions, and scoring procedures from are presented in Appendix A. Hearing Screening. To establish whether hearing was adequate for neurocognitive and theory of mind testing, candidates were screened with a portable audiometer, in a quite room, at frequencies of 500 Hz, 1000 Hz, 2000 Hz and 4000 Hz. Only those individuals who demonstrated no more than a mild-moderate, uncorrected hearing loss were selected for the present investigation. Research has indicated that elderly individuals with mild to moderate hearing loss demonstrate relatively intact speech comprehension at the word and sentence level in non-interference conditions (Divenyi & Haupt, 1997). AD Group Characteristics. A total of 28, potential AD group candidates completed part or all of the pre-selection assessment battery. Of these potential candidates, 10 met all of the inclusion criteria for AD participants, and were included in the final AD participant group. Four of these 10 AD participants had been recently diagnosed with probable Alzheimer’s type dementia by a neurologist and a memory

48 disorders clinic in the Florida panhandle area. The remaining six participants carried neurological diagnoses of memory loss or dementia, which were consistent with early stages of AD. This group consisted of eight females and two males, between the ages 75 and 94, with a group mean age of 82 years, and a standard deviation of 6.15 years. The range of education of these AD participants was 10 years to 21 years, with a mean length of education of 15.3 years, and a standard deviation of 1.77 years. Participant characteristics are presented in Table 1. All AD group members presented with AD-typical DRS-2 profiles, as described by Salmon et al. (1989). All individuals in the AD group performed at least 24% better on all other DRS-2 cognitive subscales than they did on the memory subscale, surpassing the required 15% differential performance that is characteristic of AD. In addition, within the Memory subscale of the DRS-2, all AD participants performed at least 33% lower on recall item performance than on recognition item performance. This difference in memory recall and recognition performance also surpassed the 25% selected cutoff for difference in memory-type performance that differentiates AD from other dementia types (Salmon et al., 1989). AD, DRS-2 profiles for AD participants are presented in Table 2. All 10, AD participants fell well within the pre-set criterion of scoring 4 or less on the 45 minute recall subtest of the RCF. Forty-five minute recall scores ranged from 0 to 2, with all but two participants scoring 0 on this episodic memory portion. In addition, the group mean for current AD participants of 0.04 on this episodic memory subtest was lower than the group mean of 0.1 that was reported to distinguish between AD participants and the significantly higher scores of FTD individuals (Hodges et al, 1999). Forty-five minute, RCF recall scores are presented in Table 1. AD participant, MMSE scores ranged from 17 to 23, within the range of mild to moderate cognitive impairment. Individual MMSE results are presented in Table 1. Each participant performed at an independent, 5.0 (grade five) Flesch-Kincaide Grade Reading Level, a level commensurate with theory of mind test stories which ranged from 3.7 to 5.3 on the Flesch-Kincaide scale (Flesch, Fishburne, Rogers, & Chissom, 1975). The oral reading error scores, as determined by the Stieglitz coding system, ranged from 1 to 0 (Stieglitz, 2002). Noted errors were single word omissions that did not disrupt the sentence meaning, whole word substitutions that did not disrupt

49 the sentence meaning, or self corrections. All participants demonstrated reading comprehension ability by correctly answering at least one of the two reading comprehension questions.

Table 1 AD participant characteristics, MMSE scores and RCF profiling scores.

Subject Age Years of Sex Diagnosis MMSE RCF Education 45min

AS #1 78 18 F Probable AD 19 0

AS #2 79 14 F Mild Dementia 20 0

AS #3 82 14 F Probable AD 23 2

AS #4 75 16 M Dementia 17 0

AS #5 91 16 F Dementia 20 0

AS #6 80 16 M Probable AD 21 0

AS #7 94 18 F Dementia 20 0

AS #8 83 14 F Mild Dementia 23 0

AS #9 82 13 F Short Term Mem. loss 22 2

AS #10 76 14 F Probable AD 21 0

Mean 82 15.3 20.6 0.4

SD 6.15 1.77 1.83 0.084 MMSE = Mini Mental State Examination RCF = Rey Complex Figure Test

All Alzheimer group participants exhibited an uncorrected, mild to mild-moderate hearing loss. Hearing dB levels ranged from 20 to 45 dB at 500 Hz, from 15 to 40 dB at 1000 Hz, from 20 to 40 dB at 2000 Hz, and from 20 to 60 dB at 4000 Hz. This degree of hearing loss was not of concern under the face-to-face, quiet, distraction-free testing

50 environments in which this study took place (Divenyi & Haupt, 1997). Further, all theory of mind tests, memory tests, executive function tests, and portions of tests of general cognition were supported with text and/or visual cues. Such visual support has been shown to benefit elderly individuals in speech recognition tasks (Walden, Busacco, & Montgomery, 1993).

Table 2 AD profiles on DRS-2, % correct raw score differences between memory subtest score and other subtest scores.

AD Participant #1 #2 #3 #4 #5 #6 #7 #8 #9 #10

Attention - 53% 61% 39% 76% 77% 63% 61% 41% 61% 73% Memory

Initiation - 34% 32% 28% 27% 42% 25% 24% 39% 37% 76% Memory

Construction - 64% 64% 44% 84% 88% 68% 64% 44% 64% 76% Memory

Conceptualization 59% 56% 26% 61% 67% 35% 36% 26% 44% 61% - Memory

Recognition - 89% 67% 78% 44% 33% 67% 89% 49% 52% 45% Recall DRS-2 = Dementia Rating Scale, Second Edition

Control Participants Elderly participants were recruited from a local senior center and university alumni groups in the Florida panhandle area. Control group candidates were recruited to form a comparison, control group for AD group theory of mind testing, and also to establish that theory of mind testing presented no unexpected difficulty to elderly individuals without cognitive impairment. Written, informed consent was obtained from each control group candidate prior to any interviewing or testing.

51 Control group candidates were required to speak English fluently as their first language, and were required to be of similar age and educational level as members of the AD group, to form a similar comparison group that did not differ significantly on these variables. Control group candidates were free of any neurological or psychiatric diagnosis, learning or developmental disability, and severe medical illness that might have impaired cognitive functioning, as determined by participant interview. To screen candidates for any mild, undetected potential cognitive difficulties, all candidates were required to perform within normal limits, defined as 27 or above out of 30, on the MMSE. Candidates were also required to perform within normal limits for their age and education level on the Delis-Kaplan Executive Function System (D-KEFS) Design Fluency Test (Delis, Kaplan, & Kramer, 2001), which assesses high level, executive function skills of set shifting and response inhibition, and which also is heavily loaded for attention and working memory (Delis et al, 2001). Scores on the D-KEFS Design Fluency Test were interpreted as standardized scores with a mean of 10 and a standard deviation of two, according to test scoring protocol. Of the 16 control group candidates who completed the cognitive screening, three were excluded based upon cognitive test performances below the inclusion criterion standards. None of the 13 candidates who passed the neurocognitive screening missed more than five of 48 theory of mind test questions, a criterion which was established to represent no difficulty with theory of mind test performance. Three of these successful candidates were excluded on the basis of age, to form a final group of 10, control participants who did not differ significantly from the AD group on either age or education level. The control group consisted of ten participants, six females and four males, between the ages of 71 and 88, with a group mean age of 78 years, and an age standard deviation of 6.11 years. These control participants spoke English fluently as their first language, and length of education for this group ranged from 10 to 21 years, with a group education mean of 14.8 years, and a standard deviation of 3.33 years. This control group was not significantly different from the AD group on either age (t = -1.46; p = 0.162) or years of education (t = -0.420; p = 0.681).

52 All 10 participants selected for the control group scored either 29 or 30 out of a possible 30 points on the MMSE, well above the inclusion criterion cutoff of 27, and also well above the standard impairment cutoff of 24 (Cummings & Cole, 2002; Folstein et al., 1975). Individuals who scored nearly perfectly on this test of general cognition were included because research has indicated that individuals who score below 25 have a possibility of being in the early stages of dementia (Anthony, LeResche, Niaz, Von Korff, & Folstein, 1982). In addition, all control participants scored within the normal range for their age group on the D-KEFS Design Fluency Test. Control group characteristics and test scores are presented in Table 3.

Table 3 Control group demographics and cognitive test scores.

Years of Design Fluency Subject Age Education Sex MMSE standard score

NS #1 83 12 F 30 11

NS #2 74 12 F 30 15

NS #3 73 21 F 30 16

NS #4 72 18 F 29 10

NS #5 78 16 M 30 14

NS #6 87 10 M 30 9

NS #7 75 16 M 30 13

NS #8 80 15 F 29 9

NS #9 71 16 F 30 16

NS #10 88 12 M 30 10

Mean 78 14.8 29.8 12.3

SD 6.11 3.33 0.42 2.83

53

Design

This experiment was a between-group comparison of the performance of control group, elderly participants on theory of mind tests in an unsupported memory condition, to that of elderly participants with AD profiles. The performance of AD participants was also measured in a supported memory condition, and a within-group analysis compared the performances of the AD group across the two different memory conditions. Setting Testing occurred either in participant’s homes, or in resident rooms or activity rooms in assisted living facilities. All pre-assessment selection testing and all experimental testing occurred in quiet, well-lit rooms, with the author and participant seated together at a table. Locations for testing were determined on an individual participant basis, and remained constant throughout testing. In addition, the most ideal time for testing was determined through caregiver and participant interviews, and a selected time of day for testing was kept constant throughout testing. All sessions were audio taped for subsequent scoring.

Experimental Stimuli

Theory of Mind Tasks The following tasks were used to assess theory of mind functioning of AD participants, and control participants. Two difficulty levels of theory of mind tasks were included: a first order, false belief task and a more demanding, second order, false belief task. First order, false belief task. Six first order, false belief scenarios were created by the author, based on the theory of mind tests described by Stone et al, (1998). The grade reading level of these stories, calculated by Flesch-Kincaide Grade Level Analysis, ranged from 3.7 to 4.8 (Flesch, Fishburne, Rogers & Chissom, 1975). Each false belief story was printed on 8.5 inch by 11 inch white sheets of paper in black, 16-point, Times New Roman font. These brief, simple scenarios were five to seven sentences in length.

54 Each first order, false belief story was followed by four questions. A first order, false belief test question assessed mental state inferencing ability. A comprehension control question assessed story comprehension. A memory control question assessed memory for a story detail. And a general inference control question assessed general inferencing ability by requiring the participant to make an inference about a physical aspect of the scenario. Each question was printed in 16-point, Times New Roman font on a white, 4 x 6 index card. First order scenarios, with accompanying questions, reading levels and word count are presented in Appendix B. Second order, false belief task. Six second order, false belief stories were created by the investigator, based upon the second order, false belief scenario format used by Stone et al, (1998). These were more complex than the first order scenarios; however, they remained fairly brief and simple. The reading grade levels for these stories ranged from 4.5 to 5.3 (Flesch et al., 1975). These second order scenarios were from five to nine sentences long, and were created in the same manner as first order, false belief scenarios. The same series of four questions (false belief, memory, comprehension and physical inference) were printed on separate index cards, with the exception that the false belief question was a second order, false belief question. Second order, false belief scenarios with accompanying questions, reading levels and word counts are presented in Appendix C. Control participants completed this series of 12 false belief scenarios prior to administration of these tasks to AD participants. Although these false belief scenarios were carefully created following false belief scenario templates from prior theory of mind investigations (Stone et al., 1998), it was important to establish that these scenarios presented no unexpected difficulty to elderly individuals without cognitive impairment. To this end, a criterion for control participants of no more that 5 errors on the 48 test questions was established. None of the control participants had difficulty with theory of mind test stimuli. Individual, control participant, theory of mind test scores are presented in the Results section.

55 General Cognition, Memory, and Executive Function Testing Sentence Repetition Test (SRT; Spreen & Benton, 1977). This test assesses immediate memory for sentences of increasing length. It has been shown to be sensitive to memory impairments in AD populations (Murdoch, Chenery, Wilks & Boyle, 1987). It is comprised of 22 sentences that increase in length from one word to 20 words. The maximum score on this test is 22, and the cutoff for normal functioning is 13. Delis-Kaplan Executive Function System (D-KEFS) Color-Word Interference Test (Delis, Kaplan & Kramer, 2001). This variation of the traditional Stroop Test (Stroop, 1935) taps the executive functions of shifting a perceptual set, and response inhibition, the impairment of which have been specifically implicated in executive function explanations of theory of mind impairment (Hughes et al., 1995; Ozonoff et al., 1991). The Color-Word Interference Test is comprised of four, timed conditions, with 50 items in each condition. In the first condition, Color Naming, the participant is given 90 seconds to name the color of a series of color patches (red, blue, or green). In the second condition, Word Reading, the participant has 90 seconds to name a series of written color names (red, blue, or green). In the third condition, Inhibition, the participant must name the color of the ink in which color word names are printed. And the fourth condition, Inhibition Switching, requires the participant to switch between reading the color word and naming the color in which the word is printed. Standardized maximum score on this test is 19, with an average score of 10 and standard deviation of 2. D-KEFS Design Fluency Test (Delis et al., 2001). This instrument is sensitive to the executive function component skills of set shifting and response inhibition. It is comprised of rows of boxes, each containing an array of dots. The participant is asked to create as many different designs as possible by connecting the dots using four, straight lines. In condition one, the participant is simply asked to connect the black dots, making a different design in each box. In condition two, the participant must connect only the unfilled dots to create designs, and must avoid connecting the black dots. And in condition three, the participant must alternate between connecting black dots and unfilled dots when creating designs. The standardized maximum score is 19, with a mean of 10 and standard deviation of 2.

56

Procedures

Following pre-assessment selection battery testing, AD participants completed a cognitive test battery to assess the existence and degree of general cognitive, executive functioning and memory impairment. The Sentence Repetition Task, the D-KEFS Color- Word Interference Test, and the D-KEFS Design Fluency Test, were administered during a 30 minute to hour long session, which occurred within the same week as the pre- assessment selection battery. These assessments were administered according to instruction manual testing procedures for each of these instruments. One to two days following this cognitive battery testing, AD participants completed the first theory of mind task, in a single, 30 minute to hour long session. This was either a supported or unsupported theory of mind task, according to alternating-order assignment of these two test conditions among participants. Following at least a one- week interval from this initial, theory of mind test session, AD participants completed the second and final theory of mind test session. This final theory of mind testing session occurred in whichever memory condition remained untested, either unsupported or supported. In both memory conditions, the complete set of 12, theory of mind scenarios (six first order and six second order) was presented in a unique, randomized order to each participant. A random number generator was used to set the order of story presentation for each participant. For both first and second order false belief stories, the order of questions following each scenario was also randomly presented. The order of presentation of the two, theory of mind test conditions, unsupported memory and supported memory, was alternated among participants, so that five of the ten participants received the unsupported condition first, and five received the supported memory condition first, to control for possible primacy and learning effects. Also, in both theory of mind testing conditions, two, five to 10 minute breaks occurred during testing; the first after the participant completed the fourth false belief story presentation, and the second after the participant completed the eighth false belief story presentation.

57

Unsupported Memory Theory of Mind Testing In the unsupported memory condition, theory of mind testing occurred without support for working memory. Prior to initiation of testing, the investigator gave the following instructions to the participant: I am going to give you several short stories. I am going to read the stories out loud to you. Please read along silently from your copy of the story. Pay close attention, because I am going to ask you a few questions about each story. You will need to remember the story, because I am going to take back your copy of the story before you answer the questions. Do you have any questions? The text for each theory of mind story, as previously described in the stimuli section, was then given to the participant. The investigator read each theory of mind scenario aloud to the participant, and concurrently pointed to the participant’s copy of the text to help the participant to follow along. The story text was then removed, and the printed question cards were placed, one at a time, in front of the participant. The investigator read each question aloud, and the participant verbally answered each of the questions. Each printed question was left in place until the participant provided an answer. The investigator recorded each answer on a coding sheet and later transferred these responses to a summary scoring sheet for analysis (scoring and summary sheets for theory of mind testing are presented in Appendix D). Supported Memory Theory of Mind Testing In the supported memory condition, the written text was left in place for the participant to refer to at will when answering questions. The participant instructions and testing procedures were identical to the unsupported memory condition, with the exception that participants were informed that the story text would be left in place, to help with answering the questions. The investigator gave the following instructions. I am going to give you several short stories. I am going to read the stories out loud to you. Please read along silently from your copy of the story. Pay close attention, because I am going to ask you a few questions about each story. When you answer the questions, you can look at your copy of the story to find the answers. Do you have any questions?

58 Immediately following verbal presentation of each story, and before questioning began, the investigator reminded the participant that he/she was welcome to refer to the written text while answering the questions. This single reminder was given only once for each story, just before the first question was presented, to avoid possible cuing during question answering. The investigator recorded each answer, and also recorded whether the participant referred to the available text when answering each question by writing “R” for “referred” beside the question on the coding sheet.

Data Coding and Scoring

The scoring procedure for theory of mind testing was identical for control and AD participants. Answers to each of the four questions following each first order and second order false belief story trial were scored as either correct or incorrect, with reference to a coding sheet on which pre-established correct answers for each question were listed. Answers were scored as correct when the participant responded with the pre-determined correct answer (for example, the correct choice of a room where a character might expect to find a specific object, or the true location of an object at a specific time in the story). All other answers were considered incorrect. An example summary scoring protocol for an individual subject is presented in Appendix D. Error patterns on each of the 12 false belief scenarios for each participant testing session were then analyzed for evidence of theory of mind impairment. In order for a specific theory of mind impairment to be demonstrated on a false belief story, the false belief question had to be answered incorrectly, while all three control questions associated with the story had to be answered correctly. For theory of mind impairment analysis, each completed story was categorized into one of three groups, defined as follows: ToM Pass. A story was scored as ToM Pass when all questions, control and false belief, were scored as correct. ToM Impairment. A story was categorized as ToM Impairment when the false belief question was scored as incorrect, and when all control questions were scored as correct.

59 ToM Inconclusive. A story was categorized as ToM Inconclusive when any of the control questions were scored as incorrect, regardless of the scoring of the false belief question. Using this scoring system, each AD participant received a numerical total ToM Pass score, a total ToM Impairment and a total ToM Inconclusive score for the first order and second order task in each of the two memory conditions. For ToM Inconclusive trials on which the false belief question was scored as incorrect, the types of control question errors made (memory, comprehension, and/or general inference) were analyzed to determine whether any specific control question error repeatedly coincided with false belief questions errors, thus interfering with a potential ToM Impairment scores on those trials. In addition, for supported memory testing, a letter “R” was recorded for each question on which an AD participant referred back to the story text before answering. A summary score sheet for all variables is presented in Appendix D.

Reliability

Theory of mind tasks The independent coder was briefly introduced to theory of mind testing, and the logic behind theory of mind tasks. To familiarize the independent coder with theory of mind testing, an audio taped theory of mind test session was selected, and the coder scored all 48 questions from the entire, 12 story test session, with feedback from the author given after scoring of the taped session was completed. The independent coder achieved 100% agreement with the ratings of the author on the tasks before feedback, exceeding the pre-set criterion of 90%, after just this one practice trial. Three (30%) of the theory of mind test sessions with control participants, three theory of mind sessions with AD participants in the unsupported memory condition, and three theory of mind sessions with AD participants from the supported memory condition were then rescored by the independent coder to establish scoring reliability. Each of these complete test sessions was comprised of 12 theory of mind stories, each followed by four test questions, for a total of 48 re-coded questions. Stringent, exact agreement (Repp, Dietz, Boles, Dietz & Repp, 1976) of this coding with initial scoring was

60 computed to assess the accuracy of scoring and objectivity of scoring. For exact agreement, the correct/incorrect answers to the four questions associated with each false belief story comprised a scoring interval. Agreement was achieved only when both raters agreed upon the correctness/incorrectness of participant responses to all four test questions associated with the story in question. An exact agreement index was calculated by dividing the number of intervals agreed upon by the total number of intervals included in reliability coding, and then multiplying this number by 100, for percent exact agreement. Exact reliability of 100% was achieved for theory of mind testing for the control participant group. Exact reliability for theory of mind testing for AD participants ranged from 91.6% to 100%. In this calculation of exact agreement, each theory of mind story was scored as “agreement” only if all four questions following the story were scored identically by both raters. If answers to all four questions were scored differently by the two raters, the entire scenario was scored as a disagreement. The 91.6% agreement scores resulted from scoring disagreement on a single question in each case. There were no disagreements on the scoring of false belief questions, and in no case did scoring differences result in a disparity in ToM Impairment scoring. Reliability results are presented in Table 4. Neurocognitive Tests The independent coder was not familiar with scoring of D-KEFS Design Fluency and Color Word Inference Test, or the RCF, so scoring examples of these tests were provided to familiarize the coder with scoring procedures. The independent coder then achieved above 90% reliability following one complete practice re-scoring of each of the cognitive measures employed in this investigation: 100% on MMSE re-coding, 94% on RCF recoding for 3 minute and 45 minute recall, 100% on DRS-2 recoding, 100% on SRT recoding, 100% on Design Fluency Test recoding, and 94% on Color-Word Interference timing and error recoding. Three, completed examples of each test administered to AD and control participants were chosen randomly for recoding. For instruments that required verbal responses, such as the SRT, the second coder used audio recordings of sessions for re- scoring. For tests that required written responses, such as the RCF, and the Design

61 Fluency Test, Xerox copies of participant response forms were made prior to any scoring, and the second coder used these copies when rescoring the tests. For control participants, MMSE results were rescored with 100% accuracy. Reliability of D-KEFS Design Fluency Test scoring ranged from 96.2% to 100%. For AD participants, reliability on scoring of the MMSE ranged from 96.6% to 100%. Rescoring accuracy for the DRS-2 was 100% reliable. Interrater reliability for the D-KEFS Design Fluency Test was consistently 100%, and reliability for error counts and completion time scores for the Color Word Interference Test ranged from 98% to 100%. The SRT was rescored with 100% accuracy. The RCF 3 minute delay and 45 minute delay sections were recoded with 94% to 100% reliability. Reliability results are presented in Table 4.

Data Analysis

ToM Impairment Scores and Error Scores SPSS 11.0 was used to perform all statistical analyses. Independent t-tests compared ToM Impairment scores for the control group and the AD group in the unsupported memory condition, and ToM Pass scores for the control group and the AD group in the unsupported memory condition. Paired t-tests were used to compare the ToM Impairment and ToM Pass scores of AD participants in the unsupported memory condition and the supported memory condition. For total error scores on theory of mind testing, an independent t-test compared error scores of control participants and error scores of AD participants in the unsupported memory condition, and a paired t-test compared error scores for AD participants in the supported and unsupported memory conditions. The a value for all ToM trial score and error score comparisons was set at 0.05.

62 Table 4 Inter-rater reliability on theory of mind tests and neurocognitive instruments for AD and control participants.

Instrument AD Group Reliability Control Group Reliability Range Mean Range Mean

MMSE 100% - 96.6% 98.9% 100% 100%

DRS-2 100% 100% N/A N/A

RCF 3 min. delay 100% - 94% 98% N/A N/A 45 min. delay 100% - 94% N/A N/A

SRT 100% 100% N/A

D-KEFS 100% 100% 100% - 96.2% 98.7% Design Fluency

D-KEFS 100% 100% N/A N/A Color Word Inference

Theory of Mind 100% - 91.6% 94.4% 100% 100% Unsupported Memory

Theory of Mind 100% - 91.6% 97.2% N/A N/A Supported Memory

Neurocognitive Testing SPSS 11.0 was used to calculate Pearson Product Moment correlations between AD participant ToM Impairment scores, ToM Pass scores, and neurocognitive test scores, to investigate possible relationships between theory of mind ability and skills in the cognitive domains of executive functioning, memory, and general cognitive functioning. For these Pearson Product Moment correlations, a was set at 0.05. Descriptive statistics Descriptive statistics, comprised of means, ranges and standard deviations were calculated for ToM Impairment scores, theory of mind total error scores, frequency of referral to story text in supported testing, and all neurocognitive test scores for AD and

63 control participants. In addition, for analysis of ToM Inconclusive trials for AD participants, totals for each error type that co-occured with false belief questions errors (Inconclusive scenarios with false belief errors) were calculated as a single score across tasks for each theory of mind test condition for each subject.

64

CHAPTER 4 RESULTS

Theory of Mind Impairment in AD Participants

To address the question of whether AD participants exhibited a specific theory of mind impairment, the ToM Impairment scores from the AD group in the unsupported condition were compared to control group ToM Impairment scores. ToM Impairment scores provide a strong test of whether errors in responding to questions can be attributed to a specific theory of mind deficit, as participants must get the false belief question correct, but the three control questions incorrect, for each story. The ToM Impairment trial scores for AD participants in the unsupported memory condition was not significantly different from the ToM Impairment performance of normal participants (t (18) = -1.116; p = 0.279). AD participants did perform more poorly overall on ToM testing than did control participants, however, as can be seen by the significant difference between group ToM Pass scores (t (18) = 11.124; p < 0.001). ToM Impairment score means and standard deviations for the control group and AD group in the unsupported memory condition are presented in Table 5. Control participants did not have difficulty with theory of mind testing. The mean ToM Impairment score for this group was 0.40 (SD = 0.516; range = 0 to 1). As a group, these participants received mainly ToM Pass scores on theory of mind trials (105 of 120), with occasional ToM Inconclusive scores (11 of 120) and infrequent ToM Impairment scores (4 of 120). AD participants did not demonstrate specific theory of mind impairment in the unsupported memory condition as compared to the performance of control participants. The mean ToM Impairment score for AD participants in this unsupported memory condition was 0.7 (SD = 0.67; range = 0 to 2). As a group, AD participants in this

65 unsupported memory condition averaged 2.2 ToM Pass scores, 9.1 ToM Inconclusive scores, and 0.7 ToM Impairment scores.

Table 5 First order, second order, and combined ToM trial score means and standard deviations for control, AD unsupported and AD supported groups. Group ToM Pass ToM Impairment ToM Inconclusive

1st 2nd Total 1st 2nd Total 1st 2nd Total Control Mean 5.0 5.5 10.5 0.2 0.2 0.4 0.8 0.3 1.1 SD (0.97) (0.42) (1.08) (0.42) (0.42) (0.52) (0.63) (0.67) (0.88)

AD Unsup. Mean 1.1 1.1 2.2 0.2 0.5 0.7 4.7 4.4 9.17 SD (0.99) (1.19) (2.10) (0.42) (0.52 (2.10) (0.95) (1.17) (1.97)

AD Supp. Mean 3.4 2.9 6.3 0.9 1.1 2.0 1.7 2.0 3.7 SD (1.64) (1.66) (2.41) (0.88) (0.74) (0.82) (0.94) (1.69) (2.31)

Mean scores = possible range of 0 to 6 for 1st and 2nd order trials considered separately. Mean scores = possible range of 0 to 12 for combined 1st and 2nd order trail scores.

On an individual case level, control participants rarely scored ToM Impairment during theory of mind testing. On the six, first order trials, 2 of the 10 participants received one ToM Impairment score, and the remaining 8 participants received no ToM Impairment scores. And similarly, on the six, second order scenarios, 2 participants received one ToM Impairment score, and the remaining 8 participants did not receive any ToM Impairment scores. Individual ToM Impairment scores for control participants are presented in Table 6. Individual ToM Impairment trial scores for AD participants are also presented in Table 6. On the six, first order trials, 8 of the 10 participants received no ToM Impairment scores, and the remaining 2 participants received only one ToM Impairment score. On the six, second order scenarios, 5 participants did not score ToM Impairment on any trial, and 5 received one ToM Impairment score.

66 Table 6 Number of ToM Pass, Impairment and Inconclusive trial scores (first and second order trials combined) for control participants and AD participants.

Control Unsupported AD Unsupported Supported Pass Imp Inc Pass Imp Inc Pass Imp Inc #1 10 0 2 #1 6 0 6 9 1 2 #2 11 0 1 #2 1 2 9 7 2 3 #3 12 0 0 #3 0 1 11 6 2 4 #4 11 0 1 #4 1 0 11 2 1 9 #5 10 0 2 #5 2 1 9 7 2 3 #6 9 1 2 #6 2 1 9 5 3 4 #7 12 0 0 #7 1 1 10 8 1 3 #8 10 1 1 #8 0 0 12 4 3 5 #9 11 1 0 #9 5 0 7 10 2 0 #10 9 1 2 #10 4 1 7 5 3 4 Mean 10.5 0.4 1.1 Mean 2.2 0.7 9.1 6.3 2.0 3.7 SD 1.08 0.52 0.88 2.10 2.09 1.97 2.41 0.82 2.31 Imp = ToM Impaired Inc = ToM Inconclusive Mean scores have a possible range from 0 to 12.

Effect of Memory Support on ToM Impairment Scores

To address the question of how support for memory might affect the theory of mind test performance of AD participants, ToM Impairment scores in the supported memory condition were compared to ToM Impairment scores for AD participants in the unsupported condition. AD participants received significantly more ToM Impairment scores during theory of mind testing with memory support provided than they did during unsupported theory of mind testing (t (9)= -4.33; p = .002). In addition, ToM Pass scores were significantly higher for AD participants in supported testing compared to unsupported theory of mind testing (t (9) = -6.236; p < 0.001).

67 As a group, AD participants demonstrated comparative difficulty with theory of mind in supported memory testing. The group mean ToM Impairment score was 2 (SD = 0.82; range = 1 to 3). Overall, AD participants received 63 ToM Pass scores, 37 ToM Inconclusive scores, and 20 ToM Impairment scores. ToM Impairment score means and standard deviations for AD participants in the unsupported memory condition and for AD participants in the supported memory condition are presented in Table 5. Table 6 displays individual trial scores for AD participants in this supported memory testing condition. On the six, first order trials, 3 participants scored ToM Impairment on two trials, and 3 scored ToM Impairment on one trial, while 4 participants did not score ToM Impairment on any of the six, first order trials. On the six, second order trials, 3 participants scored ToM Impairment on two trials, 5 scored ToM Impairment on one trial, and 2 did not score ToM Impairment on any trial. Evidence that participants used the memory support by referring to the text prior to answering the questions is presented in Table 7. All AD participants referred to the supporting, story text during the supported memory condition (mean = 36.7; range = 7 to 48). Only participant 4 referred infrequently (7 of 48 questions) to the story text. All other participants referred to the text fairly consistently, with 7 of the 10 participants failing to refer to the text for only 10 or fewer questions.

Error Pattern Analysis for Theory of Mind Testing

To more fully explore the findings of a potential mild ToM Impairment in these AD participants, analyses of overall error scores and error patterns across different questions types were conducted. AD participants made significantly more errors throughout unsupported theory of mind testing than did control participants (t (18) = -9.188; p < 0.001). No individuals in the control group had difficulty with theory of mind testing. The total number of errors on theory of mind tests ranged from 0 to 5, therefore all individuals met the pre-established criteria of missing no more than 5 of the 48 questions included in theory of mind testing.

68 Table 7 Frequency of referral to story text during supported condition.

Story Referral Frequency AS #1 26 AS #2 42 AS #3 38 AS #4 7 AS #5 36 AS #6 45 AS #7 48 AS #8 38 AS #9 47 AS #10 40 Mean 36.7 SD 12.21 Total possible referrals = 48

The mean error score for the control group was 1.80 (SD = 1.62). Errors on each of the four question types occurred with similar frequency in the control group as a whole; the control group missed 5 memory questions, 4 comprehension questions, 4 physical inference questions, and 5 false belief questions. No single test question was particularly difficult for the control group: only two specific question errors were repeated once; all other errors were unsystematic. All AD participants made more errors on unsupported theory of mind testing than did normal participants. Total error score means and standard deviations are presented in Table 8, and individual error scores are presented in Table 9. On average, AD participants made 21.6 errors (SD = 6.62; range = 11 to 33). As a group, AD participants made similar numbers of errors on all question types in the unsupported memory condition. On first order scenarios, participants made 30 comprehension question errors, 27 memory question errors, 23 physical inference question errors, and 25 false belief

69 question errors. On the second order scenarios, participants made 27 comprehension errors, 21 memory errors, 32 physical inference errors, and 31 false belief question errors.

Table 8 Group total error score means and standard deviations for first order trials, second order trials, and for first order and second order trials combined. Error Types Control AD

Unsupported Unsupported Supported Total Errors 1.8 (1.62) 21.6 ( 6.62) 8.4 (8.4) Mean; (SD) Total 1st 2nd Total 1st 2nd Comprehension Mean 0.4 5.7 3.0 2.7 2.0 0.9 1.1 SD (0.52) (2.06) (0.82) (1.56) (1.89) (0.88) (1.52)

Memory Mean 0.5 4.8 2.7 2.1 0.9 0.3 0.6 SD (0.71) (2.25) (1.06) (1.67) (1.29) (0.48) (0.97)

Physical Inference Mean 0.4 5.5 2.3 3.2 1.9 1.0 0.9 SD (0.97) (1.72) (0.95) (1.14) (1.52) (0.67) (0.99)

False Belief Mean 0.5 5.6 2.5 3.1 3.6 1.2 2.4 SD (0.71) (2.17) (1.27) (1.29) (1.84) (1.14) 1.51

AD participants’ theory of mind test error scores varied significantly between the supported and unsupported memory test conditions. However, unlike ToM Impairment scores, which increased with the provision of memory support, total error scores decreased significantly with memory support provided (t (9) = 8.691; p < 0.01). AD participants made an average of 13.2 fewer errors in the supported memory condition as compared to the unsupported memory condition. AD participants in the supported

70 condition made an average of 8.4 errors (SD = 5.79; range = 2 to 23). On first order scenarios, the AD group made 9 comprehension question errors, 3 memory question errors, 10 physical inference question errors, and 12 false belief question errors. On second order scenarios, the group totals for control question errors were similar to first order scenario totals. Participants made 11 comprehension questions errors, 6 memory question errors, and 9 physical inference question errors. However, the number of false belief question errors was notably higher for second order testing; AD participants made 24 false belief question errors on supported, second order scenarios as compared to the 12 false belief errors made on first order, supported theory of mind trials. Total error score means and standard deviations are presented in Table 8, and individual error scores are presented in Table 9. To explore the possibility of significant interaction effects between memory support test condition (unsupported or supported) and question type, a post hoc analysis was performed. Two Way Repeated Measures ANOVAs were performed separately for first order trials, and for second order trials. These analyses were performed with SigmaStat, and for all analyses a was set at 0.05. For first order trials, a significant main effect was found for support (F (1; 9) = 56.08; P < 0.001), however the main effect of question type was not significant (F (3; 9) = 1.84; P = 0.164). No significant interaction was found between support condition and question type for first order, theory of mind trials (F (3; 27) = 2.171; P = 0.115), however the power of this test was low (0.271). For second order trials, a significant effect was also found for support (F (1; 9) = 43.55; P < 0.001). The main effect of question type was also significant (F (3; 27) = 8.78; P < 0.001). Pairwise comparisons for question type indicated that AD participants made significantly more false belief questions errors than comprehension question errors (t (3) = 3.09; p = 0.01), than memory question errors (t (3) = 5.09; p = 0.009), and physical inference question errors (t (3) = 2.54; p = 0.017), and also that AD participants made significantly more physical inference question errors than memory question errors (t (3) = 2.55; p = 0.013). However, no significant interaction was found between support condition and question type for these second order, theory of mind trials, indicating that these significant question type differences were not dependent on the presence or absence of memory support (F (3; 27) = 2.42; P = 0.088). The power of this test to find an

71 interaction effect was low, however (0.325) so the possibility of a type II error should be considered for this analysis.

Table 9 Individual total error scores on theory of mind testing for control participants, and for AD participants in both supported and unsupported memory conditions.

Control AD

Unsupported Unsupported Supported Total Errors Total Errors Total Errors

NS #1 2 AS #1 11 3 NS #2 1 AS #2 24 7 NS #3 0 AS #3 25 8 NS #4 1 AS #4 33 23 NS #5 2 AS #5 18 6 NS #6 2 AS #6 23 9 NS #7 0 AS #7 29 6 NS #8 4 AS #8 21 10 NS #9 1 AS #9 15 2 NS #10 5 AS #10 17 10 Mean 1.80 Mean 21.6 8.4 SD 1.62 6.62 5.79 Total possible error score = 48.

Error Analysis of ToM Inconclusive Trials

ToM Inconclusive trials that contained false belief question errors were further analyzed to determine whether any single type (or types) of control question errors coincided with false belief errors most predominantly, thereby changing a potential ToM

72 Impairment score to a ToM Inconclusive score. In the unsupported memory condition, memory, comprehension, and physical inference control question errors coincided with false belief question errors with similar frequencies in the AD group as a whole. On first order scenarios AD participants made 20 memory question errors, 17 comprehension question errors, and 17 physical inference question errors coincident with false belief errors. On second order scenarios, the AD group made 18 memory, 17 comprehension, and 20 physical inference errors on trials coincident with false belief question errors. As with the unsupported condition, AD participants missed the three types of control questions coincident with false belief question errors at similar frequencies in the supported memory condition. No single type of control question error interfered predominantly with ToM Impairment scores. On first order scenarios, 1 memory, 1 comprehension, and 2 physical inference errors were made simultaneously with false belief questions errors. And on second order scenarios, 7 memory, 5 comprehension, and 8 physical inference errors were made coincident with false belief question errors.

Correlations Between Theory of Mind Scores and Neurocognitive Tests

To investigate relations between theory of mind performance and neurocognitive test performance in AD participants, ToM Impairment scores and ToM Pass scores were correlated with MMSE, DRS-2, D-KEFS Design Fluency Test, D-KEFS Color-Word Interference Test, SRT, and the RCF scores. Only one significant correlation was found between ToM Impairment scores and neurocognitive test scores for AD participants; ToM Impairment scores of AD participants in the supported memory condition were correlated with MMSE scores (r= 0.670; p = 0.034), so that higher ToM Impairment scores were associated with higher MMSE scores. Several significant correlations were found between ToM Pass scores and neurocognitive test scores. RCF 45 minute recall scores were correlated with ToM Pass scores in the unsupported memory condition (r = 0.83; p = 0.003) and with ToM Pass scores in the supported memory condition (r = 0.70; p = 0.02). The SRT test of immediate memory was also significantly correlated with unsupported ToM Pass scores (r = -0.69; p = 0.03) and supported ToM Pass scores (r = - 0.69; p = 0.03). Finally, D-KEFS Design Fluency contrast scores were significantly

73 correlated with unsupported (r = 0.87; p < 0.01) and supported (r = 0.69; p = 0.03) ToM Pass scores, so that specific difficulty with executive function skills was associated with higher ToM Pass scores. Significant correlations were also observed among neurocognitive test scores. DRS-2 scores were correlated with MMSE scores for the AD participants (r = 0.722; p = 0.02). D-KEFS Design Fluency scores were correlated with RCF scores (r = 0.81; p < 0.01), and with SRT scores (r = -0.74; p < 0.01). Correlations are presented in Table 10.

Table 10 Correlations between neurocognitive test scores and ToM trial scores for AD Participants Sup. Unsup Sup. Unsup Cont. ToM ToM ToM ToM Rey Des. r Imp. Imp. Pass Pass MMSE DRS2 Fig. SRT Fl. Unsup 0.20 ToM (0.58) Imp. Sup. -0.40 -0.42 ToM (0.26) (0.23) Pass Unsup 0.26 0.13 0.58 ToM (0.47) (0.72) (0.08) Pass MMSE 0.67* 0.19 <-0.01 0.48 (0.03) (0.61) (0.99) (0.16)

DRS2 0.42 <0.01 -0.22 0.23 0.72* (0.23) (0.99) (0.54) (0.52) 0.02

Rey -0.16 -0.16 0.70* 0.83* 0.52 0.29 Fig. (0.67) (0.66) (0.02) (<0.01) (0.12) (0.42)

SRT 0.14 0.14 -0.69* -0.69* -0.02 0.36 -0.59 (0.70) (0.70) (0.03) (0.03) (0.96) (0.31) (0.07)

Cont. 0.28 -0.25 0.69* 0.87* 0.47 0.20 0.81* -0.74* Des. (0.43) (0.49) (0.03) (<0.01) (0.17) (0.58) (<0.01) (0.01) Fl. Cont. 0.18 -0.13 0.23 0.55 0.17 0.48 0.31 -0.14 0.53 C-W (0.62) (0.72) (0.52) (0.10) (0.64) (0.16) (0.38) (0.70) (0.12) Inf. p-value in parentheses * Significant at the 0.05 level (2-tailed).

74 General Cognitive Testing On the MMSE AD participant scores ranged from 17 to 23. All participants fell within the range of mild to moderate impairment on this instrument. DRS-2 total raw scores ranged from 90 to 123, and the associated standardized AEMSS scores ranged from 0 to 4. All participants fell within the range of moderate or severe impairment on this instrument. All performed within normal limits on the Attention and Construction Subtests, and all performances were severely impaired on the Memory subtest. Performance on Initiation/ Perception and Conceptualization subtests varied among participants. General cognitive test results are presented in Table 11. Executive Function Testing On the D-KEFS Design Fluency Test, AD participants differed in the presence and degree of executive function impairment. Age-adjusted composite scale scores ranged from 8 (low average) to 3 (moderate impairment). Nine of the 10 participants performed in the mild to moderate range of impairment on at least one of the three subtests of this instrument, indicating possible general impairments in speed of cognitive processing, attention and/or working memory. Four of the 10 participants (3, 6, 9, and 10) obtained scaled contrast scores large enough to indicate specific difficulty with the executive function of set shifting, over and above primary impairments. In addition, participant 10 also exhibited difficulty with response inhibition. On the D-KEFS Color-Word Interference Test, all AD participants except AD Participant 10 exhibited primary deficits in areas of naming, speed of mental processing, and/or perseveration. Four of the ten participants (1, 3, 9, and 10) demonstrated specific executive function impairments in set shifting and in inhibition. Executive function test results are presented in Table 12. Memory Testing All AD participants performed between average and low average/ mild impairment on the SRT of immediate memory. Age and education corrected scores ranged from 18 to 13 out of a possible 22 points, with a group mean performance of 15.3. On the RCF, 3 minute recall scores ranged from 4 to 0, indicating significant difficulty in working memory skills for all AD participants. Forty-five minute recall scores ranged

75 from 2 to 0, indicating severe episodic memory impairment for all AD participants. RCF and SRT individual scores are presented in Table 11.

Table 11 Scores of AD participants on neurocognitive instruments for memory and general congnition

Participant General Cognition Memory

MMSE DRS-2 Rey Figure SRT

AS #1 19 Raw score = 111 3min delay = 0 16 AEMSS = 1 45min delay = 0

AS #2 21 Raw score = 112 3min delay = 0 18 AEMSS = 2 45min delay = 0

AS #3 23 Raw score = 118 3min delay = 4 13 AEMSS = 4 45min delay = 2

AS #4 17 Raw score = 90 3min delay = 0 15 AEMSS = 0 45min delay = 0

AS #5 20 Raw score = 93 3min delay = 0 14 AEMSS = 0 45min delay = 0

AS #6 21 Raw score = 96 3min delay = 0 14 AEMSS = 0 45min delay = 0

AS #7 20 Raw score = 101 3min delay = 0 17 AEMSS = 0 45min delay = 0

AS #8 23 Raw score = 123 3min delay = 0 16 AEMSS = 4 45min delay = 0

AS #9 22 Raw score = 109 3min delay = 2 14 AEMSS = 2 45min delay = 2

AS #10 23 Raw score = 118 3min delay = 0 16 AEMSS = 2 45min delay = 0

76

Table 12 Scores for AD participants on tests of executive function D-KEFS D-KEFS Design Fluency Color-Word Interference

Subject Composite Contrast Scaled Condition Scores Contrast Scores 1 2 3 4 1 2 3 4 5 AS# 1 5 12 1 5 1 1 10 8 10 10 6*

AS# 2 3 9 1 1 d/c d/c d/c d/c d/c d/c d/c

AS# 3 6 6* 1 7 1 4 10 10 13 13 7*

AS# 4 3 8 1 1 d/c d/c d/c d/c d/c d/c d/c

AS# 5 4 8 4 7 d/c d/c d/c d/c d/c d/c d/c

AS# 6 6 7* 1 1 d/c d/c d/c d/c d/c d/c d/c

AS# 7 5 8 6 8 5 7 9 10 12 11 9

AS# 8 8 8 1 8 d/c d/c d/c d/c d/c d/c d/c

AS# 9 8 6* 1 6 1 1 10 7* 10 10 5*

AS# 10 4 7* 10 12 1 12 1* 11 19 12 10

* indicates significant contrast scores indicating specific executive function impairment. d/c indicates testing was discontinued according to test protocol; primary deficits were judged severe enough to preclude meaningful executive function contrasts.

Case Summaries of Results for Individual AD Participants

To analyze theory of mind test performances and nerurocognitive test performances at the level of the individual, case analyses were performed for all AD participants. Results for individual participants are summarized and briefly interpreted below. More complete individual testing results and summary score tables for each AD participant are reported in Appendix E.

77 AD Participant 1 AD Participant 1 did generally quite well on theory of mind testing, and demonstrated little evidence of a specific, mental state inferencing difficulty. Out of a total of 24 ToM test trials, she scored ToM Impairment on only one, supported condition, second order trial. In addition, she answered 21 of the 23 false belief test questions correctly. Only comprehension and memory control question errors coincided with false belief errors. Support for memory decreased her number of ToM test errors from 11 to 3, so that with support provided she performed much like normal participants. Cognitive testing revealed general cognitive deficits in working and episodic memory, speed of mental processing, and initiation/ perseveration. In addition, she demonstrated a specific deficit in the executive functions of set shifting and response inhibition. AD Participant 2 AD Participant 2 demonstrated some evidence of mental state inferencing difficulty. She obtained ToM Impairment scores on 4 of 24 test trials, two unsupported and two supported, and answered only 14 of the 24 false belief questions correctly. Physical inference, control question errors coincided slightly more frequently with false belief question errors than did memory or comprehension errors. The addition of support for memory decreased her error score from 24 to 7. Cognitive testing indicated general cognitive deficits in working and episodic memory, speed of mental processing, and initiation/ perseveration, however no specific higher-level, executive functioning difficulties were observed. AD Participant 3 AD Participant 3 also demonstrated some evidence of a specific theory of mind impairment. She scored ToM Impairment on 3 of the 24 test trials, one unsupported and two supported, and she answered only 15 of the 24 false belief questions correctly. Although physical inference and comprehension control questions coincided occasionally with false belief errors, memory questions errors interfered with ToM Impairment scores most commonly. AD Participant 3 performed much better during supported memory testing, making only 8 errors as compared to her 25 errors in unsupported theory of mind testing. In cognitive testing, AD Participant 3 demonstrated impairments in working and episodic memory, a mild impairment in immediate memory, and deficits in speed of

78 mental processing. In addition, she demonstrated specific deficits in executive functions of set shifting and response inhibition, therefore it is possible that executive function impairments may have contributed to the mental inferencing difficulty demonstrated by AD Participant 3. AD Participant 4 AD Participant 4 had considerable difficulty with theory of mind testing, but he showed little evidence of a specific mental inferencing deficit. Although he answered only 8 of the 24 false belief questions correctly, almost all of these errors coincided with one or more control question errors. This pattern of performance resulted in many ToM Inconclusive scores across both memory conditions, but in only one ToM Impairment score which occurred in the supported memory condition. Errors on all three types of control questions co-occurred with false belief errors with approximately equal frequency, so that no one error type was particularly responsible for interfering with potential ToM Impairment scores. During supported theory of mind testing, AD Participant 4 was the one participant who did not frequently refer to the story text for question answers. He repeatedly stated that he wanted to try to answer without help. Although he referred to the supporting story text only 7 of 48 opportunities, he still performed considerably better during supported testing, as his error score decreased from 33 to 23. The performance of AD Participant 4 on cognitive tests indicated difficulties with episodic and working memory, speed of cognitive processing, conceptualization and initiation/ perseveration. He did not evidence a specific executive functioning difficulty over and above these cognitive deficits. AD Participant 5 AD Participant 5 exhibited some evidence of a specific, theory of mind impairment. She scored ToM impairment on 3 of the 24 test trials, one in the unsupported condition and two in the supported memory condition. Throughout theory of mind testing, AD Participant 5 answered 17 of 24 false belief questions correctly. Although all three types of control question errors coincided with false belief errors during testing, memory and comprehension errors interfered most frequently. For AD Participant 5, cognitive testing indicated general difficulties with working and episodic

79 memory, speed of mental processing, and initiation/ perseveration. No specific deficits in executive function skills were exhibited. AD Participant 6 AD Participant 6 demonstrated some evidence of a specific, theory of mind impairment. He scored ToM Impairment on 4 of the 24 test trials, one in the unsupported condition and three in the supported condition, and answered only 14 of the 24 false belief test questions correctly. All three types of control question errors co-occurred with false belief errors, however memory errors co-occurred most commonly. Cognitive testing indicated difficulties in episodic and working memory, conceptualization, speed of mental processing, and initiation/ perseveration. In addition, AD Participant 6 had specific difficulty with the executive function of set shifting, so the possibility that executive function difficulties might have contributed to his mental inferencing impairment cannot be ruled out. AD Participant 7 AD Participant 7 exhibited minimal evidence of a specific, mental inferencing deficit. She scored ToM impairment on 2 of 24 trials, one in the unsupported condition, and one in the supported condition, and she answered only 16 of the 24 false belief questions correctly. On ToM Inconclusive trials, all three types of control question errors coincided with false belief errors fairly evenly. Cognitive testing indicated general cognitive impairments in working and episodic memory, speed of mental processing, and initiation/ perseveration. AD Participant 7 did not demonstrate any specific executive function impairments. AD Participant 8 AD Participant 8 demonstrated some evidence of a specific theory of mind difficulty. She scored ToM Impairment on 3 of the 24 trials, all three in the supported memory condition and correctly answered 16 of the 24 false belief questions. On ToM Inconclusive trials, memory, physical inference and comprehension, control question errors coincided with false belief errors with approximately equal frequency. AD Participant 8 was aided by the provision of memory support; her error score decreased from 21 in the unsupported condition to 10 with supporting text available. Cognitive

80 testing indicated impairments in working and episodic memory. AD Participant 8 did not exhibit evidence of specific, executive function deficits. AD Participant 9 AD Participant 9 demonstrated slight evidence of a specific theory of mind impairment, however, overall she performed fairly well on theory of mind testing. She scored ToM Impairment on 2 of the total 24 test trials, both on second order trials in the supported memory condition. She answered 18 of the 24 false belief questions correctly, performing relatively well on questions that required mental state inferencing ability. On ToM Inconclusive trials, comprehension and physical inference control question errors coincided most frequently with false belief errors. AD Participant 9 was aided by memory support; her errors decreased from 15 to 2 when supporting story text was provided. Cognitive testing revealed difficulties with episodic and working memory, initiation and perseveration, and impairment in the executive functions of set shifting and response inhibition. It therefore remains possible that the slight difficulty with theory of mind tasks may be at least partly due to impairment of executive function abilities. AD Participant 10 AD Participant 10 exhibited some evidence of a specific impairment of mental state inferencing. She scored ToM Impairment on 4 of the 24 total test trials, one in the unsupported memory condition and three in the supported memory condition, and she answered only 11 of the 24 false belief questions correctly. On ToM Inconclusive trials AD Participant 10 made coincident errors on physical inference and false belief questions most commonly, however memory and comprehension control question errors also co- occurred with false belief errors on these trials. The provision of support for working memory during theory of mind testing enhanced her performance; her number of errors decreased from 17 to 10 with support added. Cognitive testing indicated deficits in working and episodic memory, speed of mental processing, and also revealed specific difficulty with executive functions of set shifting and response inhibition. It cannot be ruled out, therefore, that her mental state inferencing difficulties may have been at least partly caused by such executive functioning deficits.

81

CHAPTER 5 DISCUSSION

The purpose of the present study was to investigate whether individuals with AD profiles might exhibit a specific impairment of theory of mind on tests of false belief. In order to test specifically for impairment of theory of mind ability, control questions for theory of mind story comprehension, memory for story details, and general inferencing were included in theory of mind testing. To further explore any possible contribution of memory impairment to theory of mind functioning in the selected AD group, AD participants’ theory of mind ability was tested in both supported and unsupported memory conditions. Order of presentation of support for memory was counterbalanced across AD participants to control for possible practice or learning effects of this repeated testing. In addition, ToM Inconclusive trials on which an AD participants made coincident false belief and control questions errors were specifically analyzed, to determine if any one particular control question error type was predominantly responsible for “interfering” with potential ToM Impairment trials. This investigation also examined possible relations between theory of mind ability and performance on neurocognitive tests of general cognition, memory and executive functions.

Evidence of Theory of Mind Impairment in AD Participants

Very little evidence for a specific theory of mind impairment was demonstrated by AD participants during theory of mind testing with no support for memory provided. Only one AD participant (AD Participant 2) scored two ToM Impairment trials, and so exhibited a possible mild, specific difficulty with mental state inferencing. Only five AD participants scored ToM Impairment on one trial (3, 5, 6, 7, and 10). The remaining four

82 participants did not obtain any ToM Impairment scores. The degree of specific, theory of mind difficulty, measured by ToM Impairment scores, was not significantly different between the control group and the AD group in this unsupported condition. This was true even though the AD group had significantly more difficulty than the control group with the theory of mind task, as evidenced by total error scores. Although specific ToM Impairment scores indicated no group differences in specific theory of mind ability, AD participants generally performed much more poorly than did control participants on unsupported theory of mind testing. This difference is evident in the group results for ToM Pass scores, which were significantly lower for the AD participants. ToM Pass scores for control participants ranged from 9 to 12 of a possible 12, while ToM Pass scores for AD participants in this unsupported condition ranged from 0 to 6. This difference in group performance was also illustrated by overall error score disparities between the two groups. For AD participants, total error scores in this unsupported memory condition were quite high (ranging from 11 to 33 errors); significantly higher than errors produced by the control participants (which ranged from 0 to 5). It was the high number of overall errors in the unsupported condition that tended to negate potential ToM Impairment scores of AD participants. The AD group tended to miss questions of all four types with similar frequency, and this coupled with the large overall number of errors made the coincidence of false belief question errors with same- trial control questions errors quite common. It was not that AD participants performed well on false belief questions in this condition, but rather that false belief errors were rarely made in isolation, and this error pattern resulted in the general lack of a specific theory of mind impairment scores in this unsupported memory condition.

Effect of Memory Support on Theory of Mind Performance

Although little specific evidence for theory of mind difficulty was exhibited by AD participants during unsupported memory testing, when provided with story text as memory support, the AD group did demonstrate some evidence of a mild, specific impairment in theory of mind ability. The within group comparison between the AD group’s ToM Impairment performance on unsupported and supported theory of mind

83 tasks was significant. A mild theory of mind difficulty demonstrated by the AD participants appeared when supporting text was provided during theory of mind testing. This increase in ToM Impairment scores with support provided occurred coincident with an overall decrease in total errors on theory of mind testing for AD participants. Within AD group comparisons for unsupported vs. supported memory conditions were significant for both ToM Impairment scores and overall error scores, but in opposite directions. Error scores decreased significantly when support for memory was provided, while ToM Impairment scores increased significantly when support for memory was provided. This observed increase in specific, ToM Impairment scores was counter to the anticipated effect of memory support in the present study, and also counter to the impetus for supporting memory during theory of mind testing of neurogenic populations. In past studies, support for memory, whether in text, video or picture form, has been provided to control for memory impairment effects on theory of mind performance; to ensure that any observed mental state inferencing difficulty was not eradicated by provision of memory support (see for example, Stone et al., 1998; Surian & Siegal, 2001). Likewise, in the present investigation, the anticipated effect of memory support, if any, was partial alleviation of any ToM difficulty observed in the unsupported memory condition. Instead, the provision of memory support appeared to compensate for control question errors more successfully than for false belief question errors, and to ‘unmask’ what may be a mild, specific, theory of mind difficulty in these AD participants. On an individual participant level, ToM Impairment patterns were fairly consistent with group trends in this supported memory condition. For eight of the ten AD participants (1, 3, 4, 5, 6, 8, 9, and 10) the number of ToM Impairment scores increased when support was provided, as compared to their unsupported performances. And for the remaining two participants, 2 and 7, ToM Impairment scores remained constant across the two test conditions. This increase or stability in individual, ToM Impairment scores was observed coincident with a decrease in overall errors that occurred consistently for each AD participant when support for memory was provided. For these individual theory of mind test scores, see Appendix E.

84 Evidence of this differential effect of memory support on theory of mind test performance was observed not only in ToM Impairment scores, but also in an examination of overall error patterns. Support for memory enabled participants to perform better on all types of ToM test questions, as can be seen from individual error score performances, group error totals, and significant within group differences. On both first order and second order unsupported trials, group error totals for each of the four questions types (memory, comprehension, physical inference and false belief) were quite similar. On first order trials in the supported memory condition, group error scores decreased on all question types, and were spread fairly evenly across false belief, physical inference and comprehension questions types, although memory question errors were comparatively low. However, group error totals on the second order, supported memory condition were not evenly dispersed; memory question errors remained quite low, physical inference and comprehension errors were very similar, but false belief question errors were relatively high, more that twice as high as physical inference and comprehension errors, and four times higher than memory question errors. Thus, most specifically for second order trials, the provision of supporting text did not appear to aid performance on false belief errors to the same extent that it compensated for control question errors. This apparent, differential lesser effect of support on false belief questions was tested statistically, and was not found to be significant. However, the power of the statistical test used was low, and therefore an effect may be present, but undetectable with this sample size. Because the number of false belief errors was similar to the number of each type of control question error in unsupported theory of mind testing, in supported, first order testing, and also in control group testing, it is unlikely that the false belief questions were inherently more difficult that the control questions. Rather, it appears that these AD participants may have possessed a specific, mild, mental state inferencing difficulty that was thrown into relief by the temporary alleviation of co- existing deficits in other cognitive domains. Error score patterns at the individual participant level generally mirror group trends. For seven of the 10 AD participants, and seven of the eight AD participants who did demonstrate a possible specific theory of mind difficulty, (2, 3, 5, 6, 8, 9, and 10), false belief errors were the highest of all error types made in the supported memory

85 condition, and for all 10 AD participants, false belief questions were at least tied for the highest error score. As a comparison, in the unsupported memory condition, only three AD participants (2, 4, and 10) made more errors on false belief questions than any other question type. Further, for seven of the 10 AD participants (1, 3, 4, 5, 6, 8, 9, and 10) memory support compensated more effectively for errors on all control question types than it did for false belief questions. For individual theory of mind error score details, see Appendix E. The possible, mild, specific difficulty with theory of mind demonstrated by the AD group in the present study is consistent with current literature. Cuerva and colleagues (2001) reported a second order, theory of mind impairment in an AD group with general cognitive impairment levels similar to the impairments of individuals in the present study. Although the lack of control for inferencing, memory and executive function abilities in that disordered group made the claim of a specific theory of mind impairment somewhat problematic, the evidence of a specific theory of mind difficulty in individuals with AD made by Cuerva and colleagues is generally supported by the current study. In their comparison of theory of mind ability in FTDfv and AD groups, Gregory and colleagues (2002) report a significant theory of mind difficulty in their AD group, also specifically for second order false belief tasks. In addition, theory of mind testing for that AD group was supported by pictures illustrating the events of the test stories, so that their performance also represented the ability of AD participants to perform second order theory of mind tasks with support provided. Although the authors did not interpret this second order test difficulty as evidence of a specific theory of mind impairment (as previously discussed), this remains consistent with the results of Cuerva and colleagues, and with the results of the present investigation.

Individual Case Analyses: Evidence for Specific Theory of Mind Impairment

When examined individually, none of the AD participants presented with a consistent or pervasive mental state inferencing difficulty, such as has been demonstrated in some individuals with autism (Baron-Cohen & Ring, 1994). Eight of the 10 participants (2, 3, 5, 6, 7, 8, 9 and 10) presented with theory of mind performance profiles

86 that suggest a specific, mild difficulty with mental state inferencing. These participants scored ToM Impairment on between 2 and 4 test trials, and did not demonstrate competence in answering false belief questions. The two individuals who did not exhibit a specific, mental inferencing difficulty presented with different overall performance profiles on theory of mind testing. AD Participant 1 performed relatively well on theory of mind testing, particularly on supported testing. Although she did receive one ToM Impairment score in the supported memory condition, she answered most false belief questions correctly, and generally demonstrated a theory of mind ability rather than a theory of mind impairment. It is, however, noteworthy, that, as with other AD participants, the ToM Impairment score for AD Participant 1 occurred when support for memory was provided. This also was true of AD Participant 4; although he, also, did not demonstrate a specific ToM Impairment, he scored ToM Impairment on only one trial, and that was a supported memory trial. Unlike AD Participant 1, AD Participant 4 had considerable difficulty answering false belief questions; however this was accompanied by similar, elevated error levels on control questions. This pattern of performance resulted in many ToM Inconclusive trials which contained false belief errors, but which did not differentiate theory of mind difficulty from memory, comprehension or general inferencing difficulties. Therefore, although AD Participant 4 may well have possessed a specific problem with mental inferencing, his impairments in other cognitive domains impeded the parsing out of such a distinct, mentalizing difficulty. AD Participant 4 scored 17 on the MMSE, at the cutoff for the present investigation and the lowest score of the AD group. He also scored poorly relative to the rest of the AD group on most other cognitive measures. His elevated degree of general cognitive impairment may have obscured a specific theory of mind difficulty. Although the study by Cuerva and colleagues employed individuals with MMSE scores as low as 17, this single case, when compared to performance of higher functioning individuals in the present study, suggests that individuals with MMSE scores of 19 and above may be most likely to exhibit a specific ToM Impairment that can be differentiated from other cognitive deficits. In addition to his relatively impaired cognition, AD Participant 4 also was the one AD participant who did not utilize the supporting text frequently during theory of mind

87 testing. He repeatedly refused to refer to the text, stating that he wanted to answer independently. On the 7 occasions when he did refer to the text, he demonstrated an ability to locate answers and relay these appropriately. To what extent this refusal to use supporting text was caused or affected by his relatively low cognitive abilities was difficult to determine. Although the case-level evidence for specific theory of mind difficulty in the current investigation may appear to be minimal, the degree of ToM difficulty demonstrated by these AD participants is comparable to relevant literature in the degree of ToM difficulty interpreted as evidence of a specific theory of mind impairment. For example, in their previously mentioned article, Stone and colleagues (1998) attributed a specific ToM impairment to 5, high functioning individuals with orbito-frontal lesions who passed first order and second order tasks without difficulty, but whose performance was significantly lower that that of other groups on a high level, faux pas test. This faux pas test contained 10 trials, and the five, ToM Impaired participants correctly responded to 9, 6, 7, 8, and 10 of the 10 faux pas test trials, respectively. Similarly, Gregory and colleagues reported a specific theory of mind deficit based upon significant between- group differences in their sample of 19 individuals with fronto-temporal dementia, on four, different theory of mind tests. Although differences between the FTDfv group and comparison groups were significant on all four tests, on an individual level, only 7 of the 19 subjects exhibited specific theory of mind difficulty on first and second order tests, only 14 exhibited difficulty on faux pas texts, and only 8 exhibited difficulty on the Mind in the Eyes Test. Further, 6 of the 12 individuals in the AD comparison group in this study by Gregory and colleagues exhibited theory of mind impairment specifically on second order, false belief tasks, a significant, specific theory of mind impairment that is similar to the results of the present study, particularly as all theory of mind testing was supported with illustrations of the stories during testing. Cuerva and colleagues (2001) also attributed a theory of mind impairment to their AD group, however only 12 of the 34 individuals in the AD group actually exhibited any specific deficit in theory of mind ability. As with the current study, those AD individuals who did exhibit a ToM Impairment as defined by these authors, demonstrated a theory of mind difficulty most notably on second order, false belief tasks.

88

ToM Inconclusive Trials

Theory of mind test trials were scored as either Pass (when all four questions were answered correctly), Impaired (when only the false belief questions was answered incorrectly), and Inconclusive (when any of the control questions were answered incorrectly. For those ToM Inconclusive trials that also contained false belief question errors, no one type of control question error coincided predominately with false belief question errors. Group error totals for all control question error types, for all ToM test conditions, were similar. Case analyses revealed much individual variation in which types of control question errors interfered most frequently with false belief questions errors. For all but AD Participant 1, all three types of control question errors coincided with false belief question errors, to some degree; AD Participant 1 made only memory and physical inference question errors coincident with false belief errors during unsupported testing, and during supported testing, she did not make any control questions errors that coincided with false belief errors. Therefore, no conclusions about which cognitive impairment(s) might be specifically interfering with or masking a mental state inferencing deficit could be drawn from the control question performance pattern of these AD participants. Individual ToM Inconclusive score data can be found in Appendix E.

Coincidence of Cognitive Impairments with Theory of Mind Impairment

Coincident with theory of mind testing, memory, executive function and general cognitive skills were assessed in AD participants, to determine whether any of these might be partially or wholly responsible for any apparent theory of mind deficit. A significant correlation for general cognition was found between ToM impairment scores in the supported memory condition, and MMSE scores: AD participants with greater evidence of ToM Impairment tended to have higher MMSE scores, representing relatively higher general cognitive skills. Although the direction of this correlation may seem counterintuitive, it is consistent with the idea presented previously, that a specific theory of mind impairment might be most easily detected in those high-level performers who do

89 not yet exhibit marked cognitive difficulties that might mask an existing difficulty with mental state inferencing. This correlation also is consistent with the observation from the present study, that provision of supporting text during theory of mind testing may alleviate some cognitive deficits, allowing individuals to perform at a higher cognitive level, and promote the detection of an existing, underlying specific theory of mind deficit. It is therefore most likely that, rather than accounting for an observed theory of mind difficulty, a general decrease in overall cognitive skill may mask an existing mental inferencing deficit, and cause such a specific perspective taking impairment to remain undiagnosed. It should be noted that this finding is not supported by the investigation of AD individuals by Cuerva and colleagues (2001), who reported that those AD individuals who exhibited a theory of mind difficulty scored significantly lower on cognitive measures than did AD individuals who did not exhibit a theory of mind difficulty. However, because Cuerva and colleagues did not control for general inferencing ability during theory of mind testing, their definition of a specific theory of mind impairment differs from that of the current investigation, and so these results are not directly comparable. Memory performance on the Rey Complex Figure Tes, 45 minute recall for AD participants was not correlated with their ToM Impairment scores, either in the unsupported or supported condition, nor was their performance on the Sentence Repetition Test for immediate memory. Because support for memory of theory of mind story contents tended to promote the emergence of ToM Impairment rather than alleviate ToM Impairment, it is unlikely that memory deficits were responsible for any theory of mind difficulty demonstrated by this group. Although ToM Impairment scores were not correlated with memory test results, ToM Pass scores for AD participants were significantly correlated with memory test performance. Higher ToM Pass scores in both the unsupported and supported test conditions were associated with higher Rey Complex Figure 45 minute recall scores, so the direction of this relationship is what would be expected for AD participants. Episodic memory skill tended to be greater in those AD participants who also exhibited greater ability to perform well on theory of mind test trials. However, Sentence Repetition Test scores for AD participants were inversely correlated with supported and unsupported

90 ToM Pass scores, a result that seems counterintuitive, and which is not readily explainable. Deficits in executive functions of response inhibition and set shifting as measured by the D-KEFS Design Fluency and Color-Word Interference Tests were not significantly correlated with ToM Impairment scores in the AD group. However, four of the eight individuals who demonstrated specific difficulty with mental state inferencing did exhibit difficulty with set shifting, and/or response inhibition. Although the degree of executive function impairment in this AD group did not correspond with the degree of ToM Impairment, the competing hypothesis that an executive functioning impairment may have been responsible for mental state inferencing difficulties cannot be ruled out for these five individuals. However, ToM Pass scores in both unsupported and supported testing were significantly correlated with higher deficits in executive function, an association in the opposite direction of what such an executive functioning explanation of theory of mind impairment would likely predict.

Conclusions

This study presented evidence for a mild, specific, mental state inferencing impairment in moderate to high functioning individuals with AD profiles. Eight of ten AD participants demonstrated a possible mild, specific ToM Impairment, specifically when support for memory was provided. This interesting consequence of providing support during theory of mind testing suggests that these individuals may have possessed a mental inferencing difficulty which was masked by other, more prominent cognitive difficulties, and which did not emerge until support for memory was provided. Because the current study controlled for memory, comprehension of story text, and general inferencing ability, it is unlikely that any mental inferencing difficulty observed in AD participants was caused by impairment in one of these other domains. Although five of the AD participants did exhibit difficulty with the executive functions of response inhibition and/or set shifting, their performances on executive function tests were not correlated with ToM Impairment scores. The lack of correspondence between the degree of executive function difficulty and the degree of ToM difficulty makes an executive

91 function-based explanation of the observed ToM Impairments less likely, however, such an explanation cannot be ruled out for these individuals. It seems clear that different populations may present with different degrees of theory of mind impairment. If, as has been proposed in the literature, the ability to make mental state inferences is localized to one or several neuoranatomical structures, it is reasonable to suppose that such a social perspective taking ability could be impaired by degrees, and that mild theory of mind impairment might present much as has been demonstrated in the present investigation. Several investigators (Lough et al., 2001; Rowe et al., 2001; Stone et al., 1998) have presented evidence that theory of mind ability may be localized at least partly to frontal lobe structures. Recent evidence has demonstrated frontal involvement in AD, though not to the degree with which frontal deterioration has been documented in the frontal dementias. The relatively mild impairment in mental inferencing observed in AD participants, in the present investigation, and in the studies by Cuerva et al. (2001) and Gregory et al. (2002), may reflect the proportional amount of frontal involvement in early AD. To this extent, the present investigation lends support to the proposed model of a specific, neuroantomically localized theory of mind module, with frontal components. In addition, the lack of significant, direct correlations between ToM Impairment scores and scores on cognitive tests of general cognition, memory and executive functions suggests that theory of mind ability may be separable from other cognitive domains. Although a mild impairment in theory of mind such as that observed in the present investigation appears to be consistent with existent literature and with an accepted model of theory of mind localization, the question remains whether such a relatively mild, mental state inferencing impairment is clinically meaningful. Clinically significant impairments that disrupt social functioning, such as impaired decision making, decreased insight, poor interpersonal communication and lack of social inhibition, have been attributed to AD populations, and such social impairments have been linked to a specific theory of mind difficulty in populations, such as autism, in which a theory of mind impairments have been most convincingly demonstrated (Baron-Cohen and Ring,, 1994). If individuals with mild to moderate AD do tend to exhibit a specific impairment in theory of mind, it is possible that a social perspective taking-based intervention might

92 help support the socio-communicative deficits commonly associated with AD. It is not unreasonable to assume that a mild, ToM Impairment that is detectable in mild to moderate AD may persist and even worsen in moderate to severe AD, though the differential diagnosis of such a specific mental inferencing difficulty may be difficult or impossible as co-existing general cognitive impairments become exacerbated. The question, then, may become not only whether a mild, detectable ToM deficit is clinically relevant, but also whether early intervention for such an impairment might improve social functioning in later stages of AD.

Study Limitations and Future Research

Although the current study has presented some evidence for a specific, mild ToM Impairment in individuals with mild to moderate AD, this evidence is certainly not conclusive, and further investigation is needed to establish whether the present findings represent a real, and a clinical meaningful theory of mind difficulty in this population. Because the present study employed only 10 AD participants who were not randomly selected from a larger population, the generalizability of this finding is quite limited. Future studies should employ larger groups, sampled randomly, that can more easily generalize to larger AD populations. In addition, the current investigation analyzed the performance of individuals with AD in an attempt to provide a detailed description of the pattern of performance of these individuals on theory of mind tasks, and also on neurocognitive instruments. To date, with the exception of a few single case studies, the claim of a specific theory of mind impairment in neurogenic populations has generally been supported by statistically significant group performance differences, although frequently, several members of the ToM Impaired group performed quite well, or even perfectly, on theory of mind tasks. Few cases analyses of individuals within these groups have been presented. Future research should concentrate not only on establishing significant group differences that are generalizable, but on the analysis of individual ToM performances. Such analyses could compare performances of those individuals who demonstrate a specific ToM impairment with those in the same population who do not, and potentially establish a profile that

93 might predict which individuals within a given disordered population are most likely to exhibit mental state inferencing difficulties. If combined with neuroimaging research, such differential case analyses might help further delineate the neuroanatomical structures that may support a specific, theory of mind ability. Individuals in the AD group of the current investigation were profiled with two instruments that have been demonstrated to differentiate between AD and other dementias, particularly frontal dementias, which can present much like AD, particularly in the early stages. All AD participants fell well within the established cutoffs for AD profiles employed in the current investigation, all presented with the AD characteristic pervasive memory deficits with relative sparing of other cognitive abilities, and all performed quite similarly on both neurocognitive and theory of mind instruments. Future research should continue to use additional AD profiling measures which focus on a specific pattern of performance across neuropsychological instruments, such as those described in the present investigation, because current NINCDS-ADRDA standards have been demonstrated to discriminate between AD and frontal dementias with only 23% accuracy (Varma et al., 1999). In addition, future studies might profile potential AD candidates for socio-communicative deficits which could indicate a specific perspective taking difficulty, and compare theory of mind performances of AD individuals with such social functioning difficulties to those who do not exhibit such specific impairments. The present investigation presented what may be interpreted as evidence of a mild, theory of mind impairment in moderate to high level AD participants. Because those individuals with higher MMSE scores were most likely to exhibit a specific ToM Impairment, and because the AD participant with the lowest MMSE score (17) had marked general difficulty with theory of mind testing which may have obscured any existing, specific theory of mind difficulty, future researchers may wish to focus theory of mind testing on higher level AD individuals, with MMSE scores of 19 or above. The current investigation employed MMSE cutoff scores of 17 and 23, however the AD group in Gregory et al. (2002) which presented with significant, second order theory of mind difficulty, possessed an average MMSE score of 27.1, and future researchers may wish to focus testing on a much higher level, AD group.

94 All of the AD participants who exhibited some evidence of a mild, specific ToM Impairment did so during supported theory of mind testing, while only one of these AD participants exhibited a mild ToM impairment during unsupported testing. Future research should employ supported memory testing, in contrast to unsupported testing, to establish whether the effect of supported theory of mind testing observed in the present study can be reliably replicated. If support for memory during theory of mind testing does indeed consistently reveal a theory of mind impairment in individuals with AD that is not observable during unsupported testing, this would suggest that many AD individuals may possess a significant theory of mind impairment that is present, but not easily dissociated, from more pervasive cognitive impairments, and which may persist or progress in later stages of AD.

95

APPENDIX A

EXAMPLE STORY AND SCORING FOR INITIAL READING SCREENING

96 Roy has a brand new, beautiful bicycle! He rides it to the park, but he is careless. He leaves the bike by the sandbox, and goes off to play baseball with his playmates. Roy can’t even see his bike from the ball field, because it is hidden by some trees!

While Roy is playing baseball, Roy’s father comes walking through the park. He sees Roy’s abandoned bike and looks all around for Roy, but Roy is nowhere in sight. Roy’s father takes

Roy’s bike home, and locks it up safely in the garage. When Roy comes to get his bike, he is surprised and worried, because he thinks his bike may have been stolen by someone!

Screening Questions

1. Where does Roy leave his bike?

Correct responses: in the park, by the sandbox

2. Where is Roy’s bike at the end of the story?

Correct responses: in the garage, at Roy’s house

97 Scoring for determination of Reading Grade Level of 5.0 or above (Stieglitz, 2002)

Full miscue: a miscue that disrupts the intended meaning of the passage.

Half miscue: a miscue that does not disrupt the meaning of the passage.

When there is doubt, miscues are counted as Full miscues.

When all miscues are coded on the story text, the values for Full (1) and Half

(1/2) miscues are added. Miscue scores between 0 and 3 are acceptable for independent reading at the passage grade level.

Definitions and examples of types of miscues to be scored

Nonword substitution: The printed word is substituted by a nonword or word part that disrupts the intended meaning (always scored as full miscue).

Example: Pat opened a paper (pape) bag.

Whole word substitution: The printed word is substituted by a real word that disrupts the intended meaning (full)/ does not disrupt the intended meaning (half).

Example: There was once (ounce) some children who were always fighting. (full)

Example: The tightly packed center of the kernel is moist (wet). (half)

Word pronounced by the examiner: The examiner pronounces the word after a five- second hesitation. (always scored as full)

Omission: A whole word or a group of words is omitted and it disrupts the intended meaning (full)/ does not disrupt the intended meaning (half).

Example: Bill and Kim could (not) wait to build something with the snow. (full)

Example: You get a hangnail when (the) skin around your nail gets dry. (half)

98 Insertion: An extra word is added to the text and it disrupts the meaning (full)/ does not disrupt the meaning (half).

Example: The lollipop was (not) strawberry. (full)

Example: Without light, we could not (even) see.

Reversal: A word is reversed or the order of words is reversed in a sentence. (always full)

Example: At sixteen, she ran in the Olympics and won (now) a bronze medal.

Example: So far, they can’t put the small of a hamburger on a sticker (sticker on a hamburger).

Repetition: Three or more words in succession are repeated. (always full). If two or fewer words in succession are repeated, no miscue is counted.

Example: Many products are sold in supermarkets and drugstores (supermarkets

and drugstores). (full)

Example: Let’s catch the leaves (the leaves) when they fall. (no miscue)

Self-correction: Not counted as a miscue. Defined as when a miscue is corrected without assistance.

Dialect Variations: Not counted as a miscue. A reader reads orally in accordance with his or her dialect.

99

APPENDIX B

FIRST ORDER FALSE BELIEF SCENARIOS

100 First Order False Belief Scenario 1. (reading level = 4.4; word count = 73)

Dan opens a bag of cookies on the kitchen table. He takes two cookies upstairs, and eats the crumbly cookies on this bed. Dan leaves the bag of cookies sitting open on the kitchen table. After Dan leaves, Sally comes into the kitchen. Sally sees the open bag of cookies. Sally moves the cookies to the cookie jar, so they won’t get stale. Later in the day, Dan decides to get more cookies.

False belief: Where will Dan look first for the bag of cookies? (kitchen table)

Comprehension: Where is the bag of cookies at the end of the story? (cookie jar)

Memory: Where was the bag of cookies at the beginning of the story? (kitchen table)

Physical inference: Where will there be cookie crumbs? (bedroom, Dan’s bed)

First Order False Belief Scenario 2 (reading level = 3.7; word count = 74)

Bill and Patty put their new puppy into his pen in the kitchen. Patty goes to her friend’s house to play. After Patty leaves, the puppy makes a mess. Bill takes the puppy into the backyard to give him a bath. At her friend’s house, Patty asks “Would you like to come over to my house to see our new puppy?” Patty and her friend go back to Patty’s house to see the puppy.

False belief: Where will Patty look first for her puppy? (kitchen, pen)

Comprehension: Where is the puppy at the end of the story? (backyard)

Memory: Where was the puppy at the beginning of the story? (pen, kitchen)

Physical inference question: Where would be the puppy’s mess be? (pen, kitchen)

101 First Order False Belief Scenario 3 (reading level = 4.8; word count = 84)

Jenny and Sam make some pudding in the kitchen. They put the bowl of pudding in the refrigerator to cool. When they set the bowl in the refrigerator, the pudding spills a little. Then Sam goes upstairs to take a nap. While Sam is napping, Jenny takes the bowl of pudding downstairs to the basement. She puts the bowl of pudding into the big freezer, so that it will cool faster. An hour later, Sam wakes up and decides to check on the pudding.

False belief: Where will Sam look first for the bowl of pudding? (refrigerator, kitchen)

Comprehension: Where is the bowl of pudding at the end of the story? (basement, freezer)

Memory: Where is the bowl of pudding at the beginning of the story? (Kitchen, refrigerator)

Physical inference: Where would there be spilled pudding? (refrigerator, kitchen floor)

102 First Order False Belief Scenario 4 (reading level = 4.8; word count = 61)

John and his wife Margaret arrive home. They park their car in the driveway in front of their house. Margaret goes upstairs to take a shower. After Margaret goes upstairs, John decides that it is going to rain. John moves the car into the garage. Later,

Margaret remembers she is out of milk, and decides to drive to the grocery store.

False belief: Where will Margaret look first for the car? (driveway, outside, front of house).

Comprehension: Where is the car at the end of the story? (garage)

Memory: Where was the car parked at the beginning of the story? (driveway, in front of house)

Physical inference: If it rains, will it rain on the car? (no)

First Order False Belief Scenario 5 (reading level = 3.9; word count = 54)

Charlie and Kim have four cupcakes. They put the cupcakes on the kitchen table to eat later. Then Charlie leaves to go to the store. After Charlie leaves, Kim is hungry, so she sits at the kitchen table and eats all of the cupcakes. When Charlie comes home, he decides to eat a cupcake.

False belief: Where will Charlie look first for the cupcakes? (kitchen, kitchen table)

Comprehension: Where are the cupcakes at the end of the story? (gone, Kim ate them,

Kim’s stomach)

Memory: Where were the cupcakes at the beginning of the story? (kitchen, kitchen table)

Physical inference: Where will there be cupcake crumbs? (kitchen, kitchen table)

103 First Order False Belief Scenario 6 (reading level = 4.7; word count = 64)

David keeps a flashlight in his car for emergencies. One night, David’s wife,

Connie, takes the flashlight out of David’s car. She does not tell David that she is borrowing his flashlight. Connie accidentally drops the flashlight on the kitchen floor.

The glass of the flashlight breaks. Connie throws David’s flashlight in the trash. Connie does not tell David that she broke his flashlight.

False belief: Where does David think his flashlight is? (car)

Comprehension: Where is David’s flashlight at the end of the story? (kitchen, trash can)

Memory: Where was the flashlight at the beginning of the story? (car)

Physical inference: Where would there be broken glass? (kitchen floor, kitchen)

104

APPENDIX C

SECOND ORDER FALSE BELIEF SCENARIOS

105 Second Order False Belief Scenario 1 (reading level = 5.1; word count = 57)

Katie sneaks into her mother’s bedroom. Katie takes her mother’s perfume bottle from the bedroom dresser. As she picks up the perfume bottle, Katie spills some perfume. Katie’s mother looks into the bedroom. She sees Katie taking the perfume.

Katie does not see her mother. Katie takes the perfume bottle into the bathroom and locks the door.

False belief: Where does Katie think that her mom thinks the perfume bottle is?

(bedroom, dresser)

Comprehension: Where is the perfume bottle at the end of the story? (bathroom, Katie has it)

Memory: Where was the perfume bottle at the beginning of the story? (bedroom, dresser)

Physical inference: Where would there be spilled perfume? (dresser, bedroom)

106

Second Order False Belief Scenario 2 (reading level = 3.6; word count = 64)

Steve knows that he isn’t supposed to drive the car. Steve sneaks into the garage while his father is asleep. The garage is dark, and Steve accidentally kicks over a can of paint. Steve drives the car out of the garage. Steve’s father wakes up just in time to see

Steve driving off in the car. Steve parks the car at a McDonald’s restaurant.

False belief: Where does Steve think that his father thinks the car is parked? (garage, house).

Comprehension: Where is the car parked at the end of the story? (McDonalds, restaurant)

Memory: Where was the car parked at the beginning of the story? (garage)

Physical inference: Where would there be spilled paint? (garage, garage floor)

107

Second Order False Belief Scenario 3 (reading level = 4.9; word count = 127)

Amy and Carl receive a box in the mail from their grandmother. They take it into the living room to open it. Just as they begin to open the box, the phone rings. Amy goes into the kitchen to answer the phone. Carl opens the box and finds two bags of cookies.

Carl hides one bag of cookies under the sofa while Amy is talking on the phone. When he pushes the bag under the couch, some of the cookies fall out of the bag. Amy looks back into the living room just in time to see Carl hiding the bag of cookies under the couch. When Amy comes back into the living room, Carl says “Look Amy, grandma sent us one bag of cookies to share!”.

False belief: How many bags of cookies does Carl think that Amy thinks were in the box? (1)

Comprehension: Where is the other bag of cookies? (hidden under the couch)

Memory: How many bags of cookies did grandma send? (2)

Physical inference: Where will there be spilled cookies? (living room floor, under couch)

108

Second Order False Belief Scenario 4 (reading level = word count = 4.4; 91)

Mary wants to hide Peter’s birthday present. She wants to trick Peter, so he won’t be able to find his present. Mary says “Peter, close your eyes, I’m going to hide your present here in the living room”. When Peter closes his eyes, Mary runs quietly up the stairs. At the top of the stairs Mary knocks some dirt out of a potted plant. Upstairs,

Mary goes into the bedroom to hide Peter’s present. But Peter peeked! He saw Mary climb the stairs and go into the bedroom with his present.

False belief: Where does Mary think that Peter thinks his present is hidden? (living room)

Comprehension: Where is the present hidden? (bedroom, upstairs)

Memory: Where does Mary tell Peter she is hiding his present? (living room, downstairs)

Physical inference: Where would there be spilled dirt? (top of stairs, on the stairs, upstairs)

109

Second Order False Belief Scenario 5 (reading level = 5.3, word count = 98)

Lucy makes coffee, and pours it into a big mug. She leaves the mug of coffee on the kitchen counter. Then Lucy goes outside to walk the dog. Adam decides to tease

Lucy. Adam takes the mug of coffee off of the kitchen counter, and puts the mug of coffee into the refrigerator! The coffee spills a little when Adam sets the mug on the refrigerator shelf. Lucy looks in the through the kitchen window. She sees Adam moving her coffee mug! Adam closes the refrigerator door, and thinks that he has played a good trick on Lucy.

False belief: Where does Adam think that Lucy thinks her mug of coffee is? (kitchen counter)

Comprehension: Where is the mug of coffee at the end of the story? (refrigerator)

Memory: Where does Lucy leave the coffee at the beginning of the story? (kitchen counter)

Physical Inference: Where would there be spilled coffee? (refrigerator)

110

Second Order False Belief Scenario 6 (reading level = 5.2; word count = 94)

Donna gets a box of chocolates for her birthday. She puts her box of chocolates on the coffee table. Donna sits down on the couch. She eats a crumbly chocolate and a few crumbs fell down. Kevin comes into the room, and Donna offeres him a chocolate.

Then Donna goes out of the room, but she leaves the chocolates on the coffee table.

Kevin tales the box of chocolates off of the coffee table. Kevin hides the chocolates in a desk drawer. Donna secretly peeks back into the room, and sees Kevin hiding her chocolates.

False belief: Where does Kevin think that Donna thinks the chocolates are? (table, coffee table, living room)

Comprehension: Where are the chocolates at the end of the story? (desk, desk drawer, drawer)

Memory: Where were the chocolates at the beginning of the story? (coffee table, table)

Physical Inference: Where would there be chocolate crumbs? (couch, under coffee table, coffee table)

111

APPENDIX D

SCORING SUMMARY PROTOCOLS

112

Subtest Breakdown for Theory of Mind Scenarios: Scoring Summary Protocol

Scenario Scenario Memory Comprehen. Inference False Belief Classification Type Number Control Control Control Question Of Scenario First order false belief 1 +/- +/- +/- +/- Pass/Imp/Inc

(FOFB) 2 +/- +/- +/- +/- Pass/Imp/Inc

3 +/- +/- +/- +/- Pass/Imp/Inc

4 +/- +/- +/- +/- Pass/Imp/Inc

5 +/- +/- +/- +/- Pass/Imp/Inc

6 +/- +/- +/- +/- Pass/Imp/Inc

Pass ___

Impaired ___

Inconcl. ___

Second. order 1 +/- +/- +/- +/- Pass/Imp/Inc false belief (SOFB) 2 +/- +/- +/- +/- Pass/Imp/Inc

3 +/- +/- +/- +/- Pass/Imp/Inc

4 +/- +/- +/- +/- Pass/Imp/Inc

5 +/- +/- +/- +/- Pass/Imp/Inc

6 +/- +/- +/- +/- Pass/Imp/Inc

Pass ___

Impaired ___

Inconclu. ___

113 Overall Score Summary Sheet

Primary Analysis Variable Subject Score

Theory of mind impairment variables 1 ToMImp UM

1 ToMImp SM

2 ToMImp UM

2 ToMImp SM

ToMImp UM Total

ToMIMp SM Total

Executive function variables

Response Inhibition for Color-Word (RI-CW) Response Inhibition for Design Fluency (RI-DF) Set Shifting for Color-Word (SS-CW) Set Shifting for Design Fluency (SS-DF) Memory Variables

Immediate Memory (IMem)

Working Memory (WMem)

Episodic Memory (EMem)

Secondary Analysis Variables- Control Question Error Analysis False Belief error + Comprehension error (FB+Cer) False Belief error + Memory error (FB+Mer) False Belief error + Inference error (FB+Ier)

114

APPENDIX E

INDIVIDUAL CASE DATA FOR AD PARTICIPANTS

115

AD Participant 1

Theory of mind performance For AD Participant 1, the unsupported memory condition was presented second, following the supported memory condition. In the unsupported condition, AD Participant 1 did not score ToM Impairment on any trial. She answered all six false belief questions for first order scenarios correctly, and missed two of six false belief questions on second order scenarios. She received three ToM Pass scores and three ToM Inconclusive scores on both first order and second order scenarios. No control question errors coincided with false belief question errors on first order scenarios, and on second order scenarios, two memory question errors and two physical inference question errors coincided with false belief errors. She missed a total of 11 of 48 questions in this unsupported memory condition: 3 memory, 2 comprehension, 4 physical inference, and 2 false belief errors. In the supported memory condition, AD Participant 1 did not score ToM Impairment on any first order scenarios, but did score ToM Impairment on one of six, second order trials. She correctly answered all six, first order, false belief questions and five of the six, second order, false belief questions. She received five ToM Pass scores and one ToM Inconclusive score on first order tasks, and four ToM Pass scores with one ToM Inconclusive score on second order trials. No control question errors coincided with false belief question errors on any of the 12 trials. AD Participant 1 referred to the supporting text before answering 26 of the 48 questions during theory of mind testing in the memory support condition. She missed 3 of 48 questions: 1 comprehension, 1 physical inference and 1 false belief question.

116 Table 13 Theory of mind test results for AD participant #1: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #1 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0 / 6 0 / 6 0 / 12 0 / 6 1 / 6 1 / 12 Scores

ToM Pass 3 3 6 5 4 9 scores

ToM Inconcl. 3 3 6 1 2 2 Scores

False Belief 0 / 6 2 / 6 2 / 12 0 / 6 1 / 6 1 / 12 Q Errors

Total Errors 4 / 24 7 / 24 11 / 48 1 / 24 2 / 24 3 / 48 (all Q types)

Neurocognitive Testing

AD Participant 1 scored 19 on the MMSE, indicating a moderate general cognitive impairment. On the DRS-2 she received a total raw score of 111, with an age and education adjusted scale score of 1, indicating a severe cognitive impairment. AD Participant 1 scored within normal limits on Attention, Construction, and Conceptualization subtests, while Initiation/ Perseveration and Memory subtest performance was impaired, with scaled scores of 3 and 2 respectively. The performance of AD Participant 1 on tests of executive functioning was generally impaired. Her composite scaled score on the D-KEFS Design Fluency Test was 5, and was indicative of general deficiencies in working memory and speed of cognitive

117 Table 14 Neurocognitive test scores for AD Participant 1: General cognition, Memory and Executive Function tests.

Instrument Test Scores Interpretation of Performance

MMSE 19 Moderate general cognitive impairment

DRS-2 total score 111 (1) Severe general cognitive impairment Attention 33 (8) Attention = WNL Initiation/Perseveration 26 (3) Initiation/Perseveration = impairment Construction 6 (10) Construction = WNL Conceptualization 37 (11) Conceptualization = WNL Memory 9 (2) Memory = impairment Recall 0 Recognition 8

Design Fluency: Slow cognitive processing, memory Total Score 17 (5) difficulty. Contrast score 12

Color-Word Interference: Slow cognitive processing 1.Color Naming 73sec. (1) 2.Word Reading 36sec. (5) 3.Inhibition 180sec. (1) 4.Inhibition/Switching 165sec. (1) Impaired executive functioning, set Contrast Scores 10, 8, 10, 10, 6* shifting, response inhibition

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 16 Immediate memory WNL

WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

processing. Her scaled contrast score on this test was 12, indicating no evidence of higher level executive function impairment above and beyond her primary cognitive deficits. The performance of AD Participant 1 on the D-KEFS Color-Word Interference

118 Test also indicated a primary cognitive deficit in mental processing skills, with scaled scores in all conditions in the range of impairment. In addition, the scaled contrast score of 6 for Reading vs. Inhibition/ Switching suggests deficits in executive functions of set shifting and response inhibition in addition to general cognitive deficits. On the test of immediate memory, the SRT, AD Participant 1 scored 16 of 22, within normal limits for her age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the RCF, AD Participant 1 scored 0 of 36, indicating marked impairments in working memory and in episodic memory, respectively.

119 AD Participant 2

Theory of mind performance

For AD Participant 2, the unsupported memory condition was presented first, followed by the supported memory condition. In the unsupported condition, AD Participant 2 scored ToM Impairment on one of six first order trials, and also on one of six second order trials. She missed four, first order, false belief questions and missed three false belief questions on second order scenarios. She received one ToM Pass score and four ToM Inconclusive scores on first order trials. On second order scenarios she received 0 ToM Pass scores and five ToM Inconclusive scores. Two memory, two comprehension, and three physical inference control question errors coincided with false belief question errors on first order scenarios. On second order scenarios one memory, one comprehension, and two physical inference question errors coincided with false belief errors. AD Participant 2 missed 24 of 48 questions in this unsupported memory condition. She made 5 memory, 6 comprehension, 6 physical inference and 7 false belief errors. In the supported memory condition, AD Participant 2 received ToM Impairment scores on one of six first order trials, and on one of six second order trials. She correctly answered five of six, first order, false belief questions and four of the six, second order, false belief questions. She received three ToM Pass scores and two ToM Inconclusive scores on first order trials, and four ToM Pass scores with one ToM Inconclusive score on second order trials. Only one, second order, physical inference, control question error coincided with a false belief question error on any of the 12 trials. AD Participant 2 referred to the supporting text before answering 42 of the 48 questions during theory of mind testing in the memory support condition. With support for memory, she missed 7 of 48 questions, making 0 memory, 2 comprehension, 2 physical inference and 3 false belief question errors.

120

Table 15 Theory of mind test results for AD participant #2: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #2 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 1/6 1/6 2/12 1/6 1/6 2/12 Scores

ToM Pass 1 0 1 3 4 7 scores

ToM Inconcl. 4 5 9 2 1 3 Scores

False Belief 4/6 3/6 7/12 1/6 2/6 3/12 Q Errors

Total Errors 12/24 12/24 24/48 4/24 3/24 7/48 (all Q types)

Neurocognitive Testing

AD Participant 2 scored 21 on the MMSE, indicating a mild general cognitive impairment. On the DRS-2 she received a total raw score of 112, with an age and education adjusted scale score of 2, indicating a severe cognitive impairment. AD Participant 2 scored within normal limits on Attention, Construction, and Conceptualization subtests, while Initiation/ Perseveration and Memory subtest performance was impaired, with scaled scores of 3 and 2 respectively.

121

Table 16 Neurocognitive test scores for AD Participant 2: General cognition, Memory and Executive Function tests.

Instrument AS #2 Test Scores Interpretation of Score

MMSE 21 Mild Impairment

DRS-2 Total 112 (2) Severe Impairment Attention 36 (12) Attention: WNL Initiation 25 (3) Initiation: Impaired Construction 6 (10) Construction: WNL Conceptualization 36 (10) Concept.: WNL Memory 9 (2) Memory: WNL Recall 0 Recog. 6

Design Fluency: Slow mental processing, memory Total Score 11 (3) impairment Contrast score 9

Color-Word Interference: Impairments in naming and speed 1.Color Naming 90sec. (1) of mental procesing 2.Word Reading 58sec. (1) 3.Inhibition N/A 4.Inhibition/Switching N/A Contrast Scores N/A

Rey Complex Figure Impairment in working memory 3min. recall 0 Impairment in and episodic 45min. recall 0 memory

Sentence Repetition Test 18 Immediate memory WNL

WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

The performance of AD Participant 2 on tests of executive functioning was generally impaired. Her composite scaled score on the D-KEFS Design Fluency Test was 3, and was indicative of general deficiencies in working memory and speed of cognitive

122 processing. Her scaled contrast score on this test was 9, providing no indication of higher level executive function impairment. The performance of AD Participant 2 on the D-KEFS Color-Word Interference Test also indicated speed of cognitive processing and naming deficits. She received a scaled score of 1 on conditions one and two. Testing for conditions three and four was discontinued due to the severity of primary deficits and poor performance on practice trials for these conditions, in accordance with D-KEFS testing procedure. On the SRT test of immediate memory, AD Participant 2 scored 18 of 22, within normal limits for her age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the RCF, AD Participant 2 scored 0 of 36, indicating impairments in working memory and in episodic memory.

123

AD Participant 3

Theory of Mind Performance

AD Participant 3 completed the unsupported memory condition first, followed later by the supported memory condition. In the unsupported condition, AD Participant 3 scored ToM Impairment only on one of six second order trials. She missed three, first order, false belief questions and two, false belief questions on second order stories. She received no ToM Pass scores and 6 ToM Inconclusive scores on first order trials and on second order trials she received no ToM Pass scores and five ToM Inconclusive scores. Two memory, one comprehension, and two physical inference control question errors co- occurred with false belief question errors on first order scenarios. On second order scenarios one memory error and one physical inference question error coincided with false belief errors. AD Participant 3 missed 25 of 48 questions in this unsupported memory condition. Overall she made 7 memory, 5 comprehension, 8 physical inference and 5 false belief errors. In the supported memory condition, AD Participant 3 scored ToM Impairment only on two, second order trials. She correctly answered all six, first order, false belief questions but missed four of the six, second order, false belief questions. She received five ToM Pass scores and one ToM Inconclusive score on first order trials, and one ToM Pass score with three ToM Inconclusive scores on second order trials. Only two, second order, memory control question errors coincided with false belief question errors on any of the 12 theory of mind test scenarios. AD Participant 3 referred to the supporting text before answering 38 of the 48 theory of mind test questions. She missed 8 of 48 questions with memory support provided; 2 comprehension questions, 2 physical inference questions and 4 false belief questions.

124

Table 17 Theory of mind test results for AD participant #3: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #3 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 1/6 1/12 0/6 2/6 2/12 Scores

ToM Pass 0 0 0 5 1 6 scores

ToM Inconcl. 6 5 11 1 3 4 Scores

False Belief 3/6 2/6 5/12 0/6 4/6 4/12 Q Errors

Total Errors 12/24 13/24 25/48 1/24 7/24 8/48 (all Q types)

Neurocognitive Testing

AD Participant 3 scored 23 on the MMSE, indicating a mild general cognitive impairment. On the DRS-2 she received a total raw score of 118, with an age and education adjusted scale score of 4, indicating a moderate cognitive impairment. AD Participant 3 scored within normal limits on Attention, Initiation/ Perseveration, Construction, and Conceptualization subtests, while her Memory subtest performance was markedly impaired (scaled score = 2). The composite scaled score of AD Participant 3 on the D-KEFS Design Fluency Test was 6, suggesting mild deficiencies in general cognitive skills such as working memory and speed of cognitive processing. Her scaled contrast score on this test was 6, indicating an executive functioning impairment in cognitive shifting, above and beyond her primary cognitive deficits.

125

Table 18 Neurocognitive test scores for AD Participant 3: General cognition, Memory and Executive Function tests.

Instrument AS #3 Test Scores Interpretation of Score

MMSE 23 Mild cognitive impairment

DRS-2 Total 118 (4) Moderate cognitive impairment Attention 35 (10) Attention: w/i normal limits Initiation 31 (7) Initiation: w/i normal limits Construction 6 (10) Construction: w/i normal limits Conceptualization 32 (7) Concept.: w/i normal limits Memory 14 (2) Memory: Impaired Recall 0 Recognition 7 Slow cognitive processing, Design Fluency: impaired memory Total Score 20 (6) Executive Function impairment in Contrast score 6* set shifting

Color-Word Interference: Impaired speed of mental 1.Color Naming 60 sec. (1) processing, naming 2.Word Reading 32 sec. (7) 3.Inhibition 75 sec. (1) 4.Inhibition/Switching 145 sec. (4) Executive Function impairments in Contrast Scores 10, 13*, 13*, 7* set shifting and response inhibition

Rey Complex Figure 3min. recall 4 Impaired working memory 45min. recall 2 Impaired episodic memory

Sentence Repetition Test 13 Immediate memory, low average WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

The performance of AD Participant 3 on the D-KEFS Color-Word Interference Test indicated speed of cognitive processing and naming deficits; scaled scores in Color Naming, Inhibition and Inhibition/Switching conditions were below normal ranges. In

126 addition, AD Participant 3 received a low contrast score of 7 for Inhibition/Switching vs. Word Reading suggesting a specific deficit in executive skills of response inhibition and set shifting. On the test of immediate memory, the Sentence Repetition Test, AD Participant 3 scored 13 of 22, just below the normal range for her age group and education level. On the Rey Complex Figure Test, she scored 4 of 36 on the 3 minute delay, and 2 of 36 on the 45 minute delay, indicating difficulty with working memory and with episodic memory.

127

AD Participant 4

Theory of mind performance

For AD Participant 4, the unsupported memory condition was presented second, following the supported memory condition. In the unsupported condition, AD Participant 4 did not score ToM Impairment on any trial. He missed three of the six false belief questions for first order scenarios, and missed six false belief questions on second order scenarios. He received one ToM Pass and five ToM Inconclusive scores on first order scenarios. He received ToM Inconclusive scores on all six, second order trials. Two memory errors, two comprehension errors and one physical inference control question error coincided with false belief question errors on first order scenarios, and on second order scenarios five memory question errors, five comprehension question errors, and five physical inference question errors coincided with false belief errors. In this condition, he missed a total of 33 of 48 questions. These were 8 memory errors, 8 comprehension errors, 8 physical inference errors and 9 false belief errors. In the supported memory condition, AD Participant 4 scored ToM Impairment on one first order scenario, but did not score ToM Impairment on any of six second order trials. He made errors on two of the six, first order, false belief questions and five of the six, second order, false belief questions. He received two ToM Pass scores and three ToM Inconclusive scores on first order scenarios, and received ToM Inconclusive scores on all six, second order trials. In this supported condition, only one memory question error co-occurred with a false belief question error on first order trials. In second order scenarios, three memory, four comprehension, and three physical inference question errors coincided with false belief question errors. AD Participant 4 referred to the supporting text before answering 7 of the 48 questions during theory of mind testing in this memory support condition. He missed 23 of 48 questions; 4 memory, 7 comprehension, 5 physical inference and 7 false belief questions.

128

Table 19 Theory of mind test results for AD Participant 4: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #4 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 0/6 0/12 1/6 0/6 1/12 Scores

ToM Pass 1 0 1 2 0 2 scores

ToM Inconcl. 5 6 11 3 6 9 Scores

False Belief 3/6 6/6 9/12 2/6 5/6 7/12 Q Errors

Total Errors 21/24 21/24 33/48 7/24 16/24 23/48 (all Q types)

Neurocognitive Testing

AD Participant 4 scored 17 on the MMSE, indicating a moderate general cognitive impairment. On the DRS-2 he received a total raw score of 90, with an age and education adjusted scaled score of 0, indicating a severe cognitive impairment. AD Participant 4 scored within normal limits on Attention and Construction. He received a scaled score of 6 on the Conceptualization subtest, indicating a mild impairment. On subtests Initiation/ Perseveration and Memory his performance was impaired, with a scaled score of 2 on both. The performance of AD Participant 4 on tests of executive functioning was impaired. His composite scaled score on the D-KEFS Design Fluency Test was 3, indicating general deficiencies in working memory and speed of cognitive processing. His scaled contrast

129 score on this test was 8, a minimal contrast that does not indicate higher level executive function impairment above and beyond observed, general cognitive deficits.

Table 20 Neurocognitive test scores for AD Participant 4: General cognition, Memory and Executive Function tests. Standard scores are in parentheses.

Instrument AS #4 Test Scores Interpretation of Score

MMSE 17 Moderate cognitive impairment

DRS-2 Total 90 (0) Severe general impairment Attention 34 (8) Attention: WNL Initiation 16 (2) Initiation: impaired Construction 6 (10) Construction: WNL Conceptualization 30 (6) Concept.: mildly impaired Memory 4 (2) Memory: impaired Recall 0 Recognition 4

Design Fluency: Impairment in speed of mental Total Score 12 (3) processing, working memory Contrast score 8

Color-Word Interference: 1.Color Naming 68 sec. (1) Primary deficit in speed of mental 2.Word Reading 51 sec. (1) processing, working memory 3.Inhibition N/A 4.Inhibition/Switching N/A Contrast Scores N/A

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 14 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

130

The performance of AD Participant 4 on the D-KEFS Color-Word Interference Test also indicated primary cognitive impairments in areas of working memory and speed of cognitive processing. He received a scaled score of 1 on conditions one and two, and testing on conditions three and four was discontinued in accord with examination procedures, as his impaired performance on conditions one and two and on practice trials precluded effective testing of higher level executive functioning abilities with this measure. On the test of immediate memory, the Sentence Repetition Test, AD Participant 4 scored 15, within normal limits for his age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the Rey Complex Figure Test, AD Participant 4 scored 0 of 36, indicating marked impairments in working memory and in episodic memory, respectively.

131

AD Participant 5

Theory of mind performance

For AD Participant 5, the unsupported memory condition was presented first, followed by the Supported Memory condition. In the unsupported condition, AD Participant 5 received only one ToM Impairment score on one of the six, second order trials. She missed two, first order, false belief questions and two, second order, false belief questions. She received one ToM Pass score and five ToM Inconclusive scores on first order trials. On second order scenarios she received one ToM Pass score and four ToM Inconclusive scores. Two memory errors, two comprehension errors, and one physical inference control question error co-occurred with false belief question errors on first order scenarios. On second order scenarios, only one memory question, coincided with a false belief error. AD Participant 5 missed 18 of 48 questions in this unsupported memory condition. She made 5 memory, 5 comprehension, 4 physical inference and 4 false belief errors. In the supported memory condition, AD Participant 5 received ToM Impairment scores on two of six first order trials, and on none of six second order trials. She correctly answered three of six, first order, false belief questions and all of the six, second order, false belief questions. She received two ToM Pass scores and two ToM Inconclusive scores on first order trials, and five, ToM Pass scores with one ToM Inconclusive score on second order trials. Only one, first order, comprehension, control question error coincided with a false belief question error on any of the 12 trials. AD Participant 5 referred to the supporting text before answering 36 of the 48 questions during theory of mind testing in the memory support condition. With support for memory, she missed a total of 6 of 48 questions, making 1 memory error, 2 comprehension errors, and 3 false belief errors.

132 Table 21 Theory of mind test results for AD participant #5: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #5 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 1/6 1/12 2/6 0/6 2/12 scores

ToM Pass 1 1 2 2 5 7 scores

ToM Inconcl. 5 4 9 2 1 3 scores

False Belief 2/6 2/6 4/12 3/6 0/6 3/12 Q Errors

Total Errors 11/24 7/24 18/48 5/24 1/24 -6/48 (all Q types)

Neurocognitive Testing

AD Participant 5 scored 20 on the MMSE, indicating a moderate general cognitive impairment. On the DRS-2 she received a total raw score of 93, with an age and education adjusted scale score of 0, indicating a severe cognitive impairment. AD Participant 5 scored within normal limits on Attention, Construction, and Conceptualization subtests, while Initiation/ Perseveration and Memory subtest performance was impaired, with scaled scores of 3 and 2 respectively. The performance of AD Participant 5 on tests of executive functioning was impaired. Her composite scaled score on the D-KEFS Design Fluency Test was 4, suggesting general deficiencies in working memory and speed of cognitive processing. Her scaled contrast score on this test was 8, a minimal contrast that does not indicate higher level executive function impairment above and beyond her primary cognitive deficits.

133

Table 22 Neurocognitive test scores for AD Participant 5: General cognition, Memory and Executive Function tests. Standard scores are in parentheses.

Instrument AS #5 Test Scores Interpretation of Score

MMSE 20 Moderate cognitive impairment

DRS-2 93 (0) Severe cognitive impairment Attention 33 (9) Attention: WNL Initiation 20 (3) Initiation: impaired Construction 6 (10) Construction: WNL Conceptualization 31 (8) Concept.: WNL Memory 3 (2) Memory: impaired Recall 0 Recognition 3

Design Fluency: Slow cognitive processing, Total Score 15 (4) impaired working memory Contrast score 8

Color-Word Interference: Slow cognitive processing, 1.Color Naming 50 sec. (4) impaired working memory 2.Word Reading 32 sec. (7) 3.Inhibition N/A 4.Inhibition/Switching N/A Contrast Scores N/A

Rey Complex Figure Impaired working memory 3min. recall 0 Impaired episodic memory 45min. recall 0

Sentence Repetition Test 14 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

The performance of AD Participant 5 on the D-KEFS Color-Word Interference Test also suggested speed of cognitive processing and naming deficits, a scaled score of 1

134 on condition one and a scaled score of 2 on condition two. Testing for conditions three and four was discontinued due to the severity of primary deficits and poor performance on practice trials for these conditions, in accordance with D-KEFS testing procedure. On the Sentence Repetition Test of immediate memory, AD Participant 5 scored 14 of 22, within normal limits for her age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the Rey Complex Figure Test, AD Participant 5 scored 0 of 36, indicating impairments in working memory and in episodic memory.

135

AD Participant 6

Theory of mind performance

AD Participant 6 completed the unsupported memory condition second, following initial presentation of the supported memory condition. In the unsupported condition, AD Participant 6 received only one ToM Impairment score, on one of the six, second order scenarios. He missed three of six, false belief questions for first order scenarios, and also missed three false belief questions on second order scenarios. He received one ToM Pass and five ToM Inconclusive scores on first order scenarios. He received one ToM Pass and four ToM Inconclusive scores on second order trials. Three memory, two comprehension and one physical inference control question error coincided with false belief question errors on first order scenarios, and on second order scenarios, two memory errors, one comprehension question error, and one physical inference question error coincided with false belief errors. In this condition, AD Participant 6 missed a total of 23 of 48 questions. He made 7 memory errors, 6 comprehension errors, 4 physical inference errors and 6 false belief errors. In the supported memory condition, AD Participant 6scored ToM Impairment on two of six, first order scenarios, and on one of six, second order trials. He made errors on two of the six, first order, false belief questions and two of the six, second order, false belief questions. He received two ToM Pass scores and two ToM Inconclusive scores on first order scenarios, and received three ToM Pass and two ToM Inconclusive scores on second order trials. In this supported condition, no control question errors co-occurred with false belief question errors on first order trials. In second order scenarios, one memory question error and one physical inference question error coincided with false belief question errors. AD Participant 6 referred to the supporting text before answering 45 of the 48 questions during theory of mind testing. He missed 9 of 48 questions; 1 memory, 2 comprehension, 2 physical inference and 4 false belief questions.

136

Table 23 Theory of mind test results for AD Participant 6: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #6 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 1/6 1/12 2/6 1/6 3/12 scores

ToM Pass 1 1 2 2 3 5 scores

ToM Inconcl. 5 4 9 2 2 4 scores

False Belief 3/6 3/6 6/12 2/6 2/6 4/12 Q Errors

Total Errors 12/24 11/24 23/48 4/24 5/24 9/48 (all Q types)

Neurocognitive Testing

AD Participant 6 scored 21 on the MMSE, indicating a mild cognitive impairment. On the DRS-2 he received a raw score of 96, with an age and education adjusted scaled score of 0, indicating a severe cognitive impairment. AD Participant 6 scored within normal limits on Attention and Construction. He received a scaled scores of 4 on the Conceptualization subtest, 2 on the Initiation/ Perseveration subtest, and 2 on the Memory subtest, indicating impairments in these areas.

137

Table 24 Neurocognitive test scores for AD Participant 6: General cognition, Memory and Executive Function tests.

Instrument AS #6 Test Scores Interpretation of Score

MMSE 21 Mild cognitive impairment

DRS-2 Total 96 (0) Severe cognitive impairment Attention 35 (10) Attention: WNL Initiation 21 (2) Initiation: Impaired Construction 6 (10) Construction: WNL Conceptualization 26 (4) Concept.: Impaired Memory 8 (2) Memory: Impaired Recall 0 Recognition 6 Slow cognitive processing, working Design Fluency: memory difficulty Total Score 20 (6) Executive Function difficulty with Contrast score 7* set shifting

Color-Word Interference: 1.Color Naming 90 sec. (1) Slow cognitive processing, working 2.Word Reading 56 sec. (1) memory impairment 3.Inhibition N/A 4.Inhibition/Switching N/A Contrast Scores N/A

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 14 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

The performance of AD Participant 6 on tests of executive functioning was impaired. His composite scaled score on the D-KEFS Design Fluency Test was 6, suggesting deficiencies in working memory and speed of cognitive processing. His

138 scaled contrast score on this test was 7, indicating higher level executive function impairment in set shifting, above and beyond general cognitive difficulties. The performance of AD Participant 6 on the D-KEFS Color-Word Interference Test also indicated general cognitive impairments in areas of working memory and speed of cognitive processing. He received a scaled score of 1 on conditions one and two, and testing on conditions three and four was discontinued in accord with examination procedures, as his impaired performance on conditions one and two and on practice trials precluded effective testing of higher level executive functioning abilities with this measure. On the test of immediate memory, the Sentence Repetition Test, AD Participant 6 scored 14 of 22, within normal limits for his age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the Rey Complex Figure Test, AD Participant 6 scored 0 of 36, indicating marked impairments in working memory and in episodic memory.

139

AD Participant 7

Theory of mind performance

For AD Participant 7, the unsupported memory condition was presented first, followed by the supported memory condition. In the unsupported condition, AD Participant 7 scored ToM Impairment on one first order trial, and did not score ToM Impairment on any second order trials. She missed four of six, false belief questions on first order scenarios, and also missed four of six, false belief questions on second order scenarios. She received no ToM Pass scores, and five ToM inconclusive scores on first order scenarios, and received one ToM Pass and five ToM Inconclusive scores on second order stories. Two memory, 3 comprehension, and 2 false belief question errors co- occurred with false belief errors on first order scenarios, and this same error pattern occurred on second order scenarios. She missed a total 29 of 48 questions in this unsupported memory condition, 6 memory questions, 8 comprehension questions, 7 physical inference questions, and 8 false belief questions. In the supported memory condition, AD Participant 7 did not score ToM Impairment on any first order scenarios, but did score ToM Impairment on one of six, second order trials. She correctly answered all six, first order, false belief questions and four of the six, second order, false belief questions. She received four ToM Pass scores and two ToM Inconclusive scores on first order tasks, and four ToM Pass scores with one ToM Inconclusive score on second order trials. No control question errors coincided with false belief question errors on any of the first order trials. Only one memory control question co-occurred with a false belief question error on second order trials. AD Participant 7 referred to the supporting text before answering 48 of the 48 questions during theory of mind testing in the memory support condition. She missed 6 of 48 questions, 2 memory, 1 comprehension, 1 physical inference and 2 false belief questions.

140

Table 25 Theory of mind test results for AD Participant 7: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #7 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 1/6 0/6 1/12 0/6 1/6 1/12 Scores

ToM Pass 0 1 1 4 4 8 scores

ToM Inconcl. 5 5 10 2 1 3 scores

False Belief 4/6 4/6 8/12 0/6 2/6 2/12 Q Errors

Total Errors 15/24 14/24 29/48 3/24 3/24 6/48 (all Q types)

Neurocognitive Testing

AD Participant 7 scored 20 on the MMSE, indicating a moderate general cognitive impairment. On the DRS-2 she received a total raw score of 101, with an age and education adjusted scale score of 0, indicating a severe cognitive impairment. AD Participant 7 scored within normal limits on Attention, Construction, and Conceptualization subtests, while Initiation/ Perseveration and Memory subtest performance was impaired, with scaled scores of 5 and 2 respectively. The performance of AD Participant 7 on tests of executive functioning was generally impaired. Her composite scaled score on the D-KEFS Design Fluency Test was 5, and her performance indicated general deficiencies in working memory, speed of cognitive processing and also suggested perseverative tendencies. Her scaled contrast score on this

141

Table 26 Neurocognitive test scores for AD Participant 7: General cognition, Memory and Executive Function tests.

Instrument AS #7 Test Scores Interpretation of Score

MMSE 20 Moderate cognitive impairment

DRS-2 Total 101 (0) Severe cognitive impairment Attention 36 (12) Attention: WNL Initiation 22 (5) Initiation: Impaired Construction 6 (10) Construction: WNL Conceptualization 28 (7) Concept.: WNL Memory 9 (2) Memory: Impaired Recall 0 Recognition 8

Design Fluency: Slow cognitive processing, working Total Score 16 (5) memory difficulty Contrast score 8

Color-Word Interference: Slow cognitive processing, 1.Color Naming 47 sec. (6) perseverative tendencies 2.Word Reading 30 sec. (8) 3.Inhibition 132 sec. (5) 4.Inhibition/Switching 120 sec. (7) Contrast Scores 9, 10, 12, 11, 9

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 17 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

test was 8, indicating no evidence of higher level executive function impairment above and beyond her general cognitive deficits.

142 On the D-KEFS Color-Word Interference Test, AD Participant 7 also displayed slow cognitive processing and perseveration, with her scaled score of 6 on condition one (Color Naming) and of 5 on condition three (Inhibition) suggesting impairments in these areas. None of the five contrast measures indicated specific executive function difficulties. On the Sentence Repetition Test, AD Participant 7 scored 17 of 22, within normal limits for her age group and education level. On both the 3 minute recall and the 45 minute recall subtests of the Rey Complex Figure Test, AD Participant 7 scored 0 of 36, indicating marked impairments in working memory and in episodic memory.

143

AD Participant 8

Theory of mind performance

For AD Participant 8, the unsupported memory condition was presented second, following the supported memory condition. In the unsupported condition, AD Participant 8 did not score ToM Impairment on any of the 12 first or second order trials. She answered five of six false belief questions for first order scenarios correctly, and three of six false belief questions on second order scenarios correctly. She received ToM Inconclusive scores on all six, first order scenarios, and also on all six, second order scenarios. On first order trials, only one, memory, control question error co-occurred with a false belief question error. On second order trials, 1 memory error, 3 comprehension errors, and 1 physical inference error co-occurred with false belief errors. AD Participant 8 missed a total 21 out of 48 questions in this unsupported memory condition, making 3 memory errors, 8 comprehension errors, 6 physical inference errors and 4 false belief errors. In the supported memory condition, AD Participant 8 received a ToM Impairment score on two, first order scenarios, and on one, second order scenario. She correctly answered four of the six, first order, false belief questions and four of the six, second order, false belief questions. She received one ToM Pass score and three ToM Inconclusive scores on first order trials, and three ToM Pass scores with two ToM Inconclusive score on second order trials. No control question errors coincided with false belief question errors on any of the first order trials. Only one, physical inference, control question co-occurred with a false belief question error on second order trials. AS 8 referred to the supporting text before answering 38 of the 48 questions during theory of mind testing in the memory support condition. She missed 10 of 48 questions; 1 memory, 2 comprehension, 3 physical inference and 4 false belief questions.

144

Table 27 Theory of mind test results for AD participant 8: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #8 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 0/6 0/12 2/6 1/6 3/12 Scores

ToM Pass 0 0 0 1 3 4 scores

ToM Inconcl. 6 6 12 3 2 5 Scores

False Belief 1/6 3/6 4/12 2/6 2/6 4/12 Q Errors

Total Errors 9/24 12/24 21/48 6/24 4/24 10/48 (all Q types)

Neurocognitive Testing

AD Participant 8 scored 23 on the MMSE, indicating a mild cognitive impairment. On the DRS-2 she received a total raw score of 123, with an age and education adjusted scale score of 4, indicating a moderate cognitive impairment. AD Participant 8 scored within normal limits on Attention, Initiation/ Perseveration, Construction, and the Conceptualization subtest. Only her performance on the Memory subtest was impaired, on which she received a scaled score of 2. AD Participant 8 received a composite scaled score on the D-KEFS Design Fluency Test of 8, within normal limits for her age group. Her scaled contrast score on this test was 8, indicating no evidence of executive function difficulties. On the D-KEFS Color-Word Interference Test, AD Participant 8 received a scaled score of 1 on condition

145 Table 28 Neurocognitive test scores for AD Participant 8: General cognition, Memory and Executive Function tests.

Instrument AS #8 Test Scores Interpretation of Score

MMSE 23 Mild cognitive impairment

DRS-2 Total 123 (4) Moderate cognitive impairment Attention 36 (12) Attention: WNL Initiation 35 (10) Initiation: WNL Construction 6 (10) Construction: WNL Conceptualization 32 (7) Concept: w/i normal limits Memory 14 (2) Memory: Impaired Recall 2 Recognition 7

Design Fluency: Overall score w/i normal limits Total Score 24 (8) Contrast score 8

Color-Word Interference: 1.Color Naming 90 sec. (1) Possible naming impairment 2.Word Reading 31 sec. (8) 3.Inhibition N/A 4.Inhibition/Switching N/A Contrast Scores N/A

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 16 Immediate memory: WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

one, Color Naming, indicating a possible naming impairment. She received a scaled score of 8 on condition two, Word Reading, which is within normal limits for her age group. Due apparently to her difficulty with color naming, she was not able to perform

146 adequately on practice trials for Inhibition and Inhibition/ Switching conditions, and so conditions three and four were discontinued. On the Sentence Repetition Test for immediate memory, AD Participant 8 scored 16 of 22, within normal limits for her age group and education level. On both the 3 minute delay and the 45 minute delay subtests of the Rey Complex Figure Test, AD Participant 8 scored 0 of 36, indicating marked impairments in working memory and in episodic memory.

147

AD Participant 9

Theory of mind performance

AD Participant 9 completed the unsupported memory condition first, followed later by the supported memory condition. In the unsupported condition, AD Participant 9 did not score ToM Impairment on any of the six first order or six second order trials. She missed two, first order, false belief questions and two, second order, false belief questions. She received two ToM Pass scores and four ToM Inconclusive scores on first order scenarios, and received three ToM Pass scores with three Tom Inconclusive scores on second order scenarios. One memory, one comprehension, and two physical inference control question errors co-occurred with false belief question errors on first order scenarios. On second order scenarios, two comprehension errors, and one physical inference error coincided with false belief errors. AD Participant 9 missed 15 of 48 questions in this unsupported memory condition. Overall she made 1 memory error, 6 comprehension errors, 4 physical inference errors and 4 false belief errors. In the supported memory condition, AD Participant 9 scored ToM Impairment only on two, second order trials. She correctly answered all six, first order, false belief questions but missed two of the six, second order, false belief questions. She received six ToM Pass scores on first order trials, and four ToM Pass scores on second order trials. She did not receive ToM Inconclusive scores on any of the 12 trials in this supported condition. AD Participant 9 referred to the supporting text before answering 47 of the 48 theory of mind test questions. She missed 2 of 48 questions with memory support provided, and these were both false belief question errors.

148 Table 29 Theory of mind test results for AD Participant 9: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #9 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 0/6 0/12 0/6 2/6 2/12 Scores

ToM Pass 2 3 5 6 4 10 scores

ToM Inconcl. 4 3 7 0 0 0 Scores

False Belief 2/6 2/6 4/12 0/6 2/6 2/12 Q Errors

Total Errors 8/24 7/24 15/48 0/24 2/24 2/48 (all Q types)

Neurocognitive Testing

AD Participant 9 scored 22 on the MMSE, indicating a mild cognitive impairment. On the DRS-2 she received a total raw score of 109, with an age and education adjusted scale score of 2, indicating a severe cognitive impairment. AD Participant 9 scored within normal limits on Attention, Construction, and Conceptualization subtests, while her Initiation/ Perseveration (scaled score = 4) and Memory (scaled score = 2) subtest performances were markedly impaired.

149 Table 30 Neurocognitive test scores for AD Participant 9: General cognition, Memory and Executive Function tests.

Instrument AS #9 Test Scores Interpretation of Score

MMSE 22 Mild cognitive impairment

DRS-2 Total 109 (2) Severe cognitive impairment Attention 36 (12) Attention: WNL Initiation 27 (4) Initiation: Impaired Construction 6 (10) Construction: WNL Conceptualization 31 (7) Concept.: low normal Memory 9 (2) Memory: Impaired Recall 1 Recognition 6

Design Fluency: Executive Function impairment in Total Score 19 (8) set shifting Contrast score 6*

Color-Word Interference: General difficulty with speed of 1.Color Naming 90 sec. (1) cognitive processing, working 2.Word Reading 35 sec. (6) memory and naming 3.Inhibition 180 sec. (1) Executive Function impairment in 4.Inhibition/Switching 180 sec. (1) response inhibition and set shifting Composite Scores 10, 7*, 10, 10, 5*

Rey Complex Figure 3min. recall 2 Impaired working memory 45min. recall 2 Impaired episodic memory

Sentence Repetition Test 14 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

The composite scaled score of AD Participant 9 on the D-KEFS Design Fluency Test was 8, indicating an overall performance score within normal limits. However, her scaled score for condition 3 was 4, indicating a specific impairment on this more

150 demanding subtest. Accordingly, her scaled contrast score on this test was 6, indicating an executive functioning impairment in set shifting. AD Participant 9 received scaled scores in the range of impairment on all four of the D-KEFS Color-Word Interference Test conditions. These scores suggest general impairments in speed of cognitive processing, working memory and naming. In addition, AD Participant 9 received low contrast scores on two of the five condition contrasts; 7 for Inhibition/Switching vs. Word Reading/ Color Naming and 5 for Inhibition/ Switching vs. Word Reading. These contrast scores indicate a specific deficit in executive skills of inhibition and set shifting. On the Sentence Repetition Test of immediate memory, AD Participant 9 scored 14 of 22, within normal limits for her age and education. On the Rey Complex Figure Test, she scored 2 of 36 on the 3 minute delay and on the 45 minute delay, indicating difficulty with working memory and with episodic memory.

151

AD Participant 10

Theory of mind performance

AD Participant 10 completed the unsupported memory condition second, following the supported memory condition. In the unsupported condition, AD Participant 10 did not score ToM Impairment on any of the six first order trials, but did score ToM impairment on one, second order trial. She missed three, first order, false belief questions and four, second order, false belief questions. She received two ToM Pass scores and four ToM Inconclusive scores on first order scenarios, and received two ToM Pass scores with three Tom Inconclusive scores on second order scenarios. Two memory errors, one comprehension error, and two physical inference control question errors co-occurred with false belief question errors on first order scenarios. On second order scenarios, one comprehension error, and two physical inference errors coincided with false belief errors. AD Participant 10 missed 17 of 48 questions in this unsupported memory condition. Overall she made 3 memory errors, 3 comprehension errors, 4 physical inference errors and 7 false belief errors. In the supported memory condition, AD Participant 10 scored ToM Impairment on one, first order scenario, and on two, second order trials. She correctly answered four of six, first order, false belief questions but only correctly answered two of the six, second order, false belief questions. She received four ToM Pass scores and 1 ToM Inconclusive score on first order trials, and one ToM Pass score with three ToM Inconclusive scores on second order trials. AD Participant 10 referred to the supporting text before answering 40 of the 48 theory of mind test questions. She missed 10 of 48 questions with support provided; these were one comprehension, three physical inference and six false belief questions.

152 Table 31 Theory of mind test results for AD Participant 10: Pass, Impairment and Inconclusive ToM trial scores, and theory of mind error scores.

AS #10 Unsup. Unsup. Total for Supported Supported Total for ToM scores 1st order 2nd order Unsup. 1st order 2nd order Supported trials trials ToM trials trials trials ToM trials

ToM Impair. 0/6 1/6 1/12 1/6 2/6 3/12 scores

ToM Pass 2 2 4 4 1 5 scores

ToM Inconcl. 4 3 7 1 3 4 scores

False Belief 3/6 4/6 7/12 2/6 4/6 6/12 Q Errors

Total Errors 10/24 7/24 17/48 3/24 7/24 10/48 (all Q types)

Neurocognitive Testing

AD Participant 10 scored 21 on the MMSE, indicating a mild cognitive impairment. On the DRS-2 she received a total raw score of 118, with an age and education adjusted scale score of 2, indicating a severe cognitive impairment. AD Participant 10 scored within normal limits on Attention, Initiation/ Perseveration, Construction, and Conceptualization subtests, while Memory subtest scaled score of 2 indicated marked impairment. The composite scaled score of AD Participant 10 on the D-KEFS Design Fluency Test was 4, suggesting general cognitive impairment of speed of cognitive processing, working memory, and perseveration. Her scaled contrast score on this test was 7, indicating a specific executive functioning impairment in set shifting. Her differential performance between conditions 1 and 2 (scaled scores of 7 and 5, respectively) also suggests impairment in the executive function of inhibition.

153

Table 32 Neurocognitive test scores for AD Participant 10: General cognition, Memory and Executive Function tests.

Instrument AS #10 Test Scores Interpretation of Score

MMSE 21 Mild Cognitive Impairment

DRS-2 Total 118 (2) Severe cognitive impairment Attention 36 (12) Attention: WNL Initiation 37 (12) Initiation: WNL Construction 6 (10) Construction: WNL Conceptualization 33 (8) Concept.: WNL Memory 6 (2) Memory: Impaired Recall 0 Recognition 4 Slow cognitive processing, Design Fluency: impaired working memory Total Score 15 (4) Executive Function deficits in set Contrast score 7* shifting and response inhibition

Color-Word Interference: General impairments in speed of 1.Color Naming 33 sec. (10) cognitive processing, working 2.Word Reading 21 sec. (12) memory 3.Inhibition 140 sec. (1) 4.Inhibition/Switching 61 sec. (12) Executive Function impairments in Contrast Scores 1*, 11, 19*, 12, 10 set shifting and response inhibition

Rey Complex Figure 3min. recall 0 Impaired working memory 45min. recall 0 Impaired episodic memory

Sentence Repetition Test 16 Immediate memory WNL WNL = within normal limits * indicates significant executive function test contrast score Standard scores are presented in parentheses

154 AD Participant 10 received scaled scores in the range of impairment on all four of the D-KEFS Color-Word Interference Test conditions. These scores suggest general impairments in speed of cognitive processing and working memory. AD Participant 10 received a low contrast score of 1 on Inhibition vs. Color Naming, indicating a specific impairment in the executive function of inhibition. In addition, she consistently failed to shift her focus during the Inhibition/ Switching condition, which resulted in a very high error rate on this condition. This high error rate due to a lack of switching suggests impairment in the executive function of set shifting. On the Sentence Repetition Test of immediate memory, AD Participant 10 scored 16, within normal limits for her age and education. On the Rey Complex Figure Test, she scored 0 of 36 on the 3 minute delay and on the 45 minute delay, indicating impairment in working memory and in episodic memory.

155

APPENDIX F

HUMAN SUBJECTS APPROVAL LETTER

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157

APPENDIX G

INFORMED CONSENT FORMS

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159

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163

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BIOGRAPHICAL SKETCH

Gina L. Youmans received a Bachelor of Science degree in Psychology from The Florida State University in Tallahassee, Florida. She then entered the Neuroscience graduate program at The Florida State University, and completed her Master of Science degree. She then enrolled in the Department of Speech and Hearing Sciences graduate program at The University of North Carolina at Chapel Hill. After receiving her Master of Science degree in Speech and Hearing Sciences, Gina worked for two years as a rehabilitation, outpatient, and acute care speech language pathologist in a medical center in Fayetteville, North Carolina, where she specialized in diagnosis and treatment of individuals with language and cognitive difficulties due to stroke, dementia, and traumatic brain injury. During her doctoral program, Gina has continued to work with individuals with cognitive-linguistic disorders, particularly in areas of aphasia and dementia. Gina’s areas of interest include aphasia, right-hemisphere disorder, dementia, traumatic brain injury, and neuroscience.

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