International Psychogeriatrics: page 1 of 21 C International Psychogeriatric Association 2013 doi:10.1017/S1041610213001233 A literature review of spaced-retrieval interventions: a direct memory intervention for people with dementia ........................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................... Alexandra S. Creighton, Eva S. van der Ploeg and Daniel W. O’Connor Aged Mental Health Research Unit, School of Psychology and Psychiatry, Monash University, Cheltenham, Victoria, Australia ABSTRACT Background: With the increasing prevalence of dementia, there is a pressing need to identify effective interventions that prolong independent functioning. As pharmacological interventions aimed at slowing cognitive decline have been found to have a number of limitations, research has now moved toward studying complementary non-pharmacological cognitive training interventions. This review describes the use of spaced- retrieval as a method to teach new information and reduce behavioral problems in people with dementia. Methods: We searched the databases PsychINFO, MEDLINE, and Scopus as well as reference lists of relevant papers to identify articles describing the use of spaced-retrieval with people with dementia. Only primary, peer-reviewed research published in English was included in this review. Results: In total, 34 studies were identified, three of which were randomized controlled trials. We found that across studies, there was wide variability with regard to design, methodology, and outcome measures used. Nonetheless, the existing research demonstrates that spaced-retrieval training can be successfully used to teach people with dementia new and previously known face- and object–name associations, as well as cue–behavior associations aimed at alleviating problem behaviors and improving functional skills. The method can also assist with the recollection of past events. Conclusions: Current evidence indicates that spaced-retrieval training is effective in enabling people with dementia to learn new information and behavioral strategies. Future research should attempt to address the limitations outlined in this review and focus on utilizing this technique to achieve more functional and clinically relevant outcomes. Recommendations are also made with regard to investigating potential secondary benefits of spaced-retrieval and strengthening study design. Key words: spaced-retrieval training, dementia, memory, cognitive training, non-pharmacological, intervention, rehabilitation, learning Introduction pharmacological memory interventions to alleviate the cognitive deficits associated with dementia. With the elderly people now the fastest-growing seg- Numerous interventions capitalize on the relatively ment of the general population (Thies and Bleiler, intact implicit memory system, which utilizes an 2012), dementia has become one of the most automatic and unconscious form of remembering common and serious medical problems (Dramé that is expressed through the performance of skills et al., 2012). Given that memory impairment is and habits (see Grandmaison and Simard, 2003 for the earliest and most invalidating core symptom of a review). dementia, the majority of early interventions aim to One such technique is that of spaced-retrieval slow cognitive decline. Currently, pharmacological (SR) training, a direct memory intervention that interventions, such as cholinesterase inhibitors, are teaches new information via active recall attempts most commonly used to achieve this (Aderinwale over progressively longer retention intervals (Camp, et al., 2010). However, studies into their use with 2006). Originally based on early work by Landauer people with dementia have found them to have lim- and Bjork (1978), Camp (1989) adapted SR for ited effectiveness (Evans et al., 2004). Thus, recent people with dementia, finding that the use of research has focused on developing alternative, non- performance-adjusted delays between recall trials enabled participants to successfully learn and retain Correspondence should be addressed to: Professor Daniel O’Connor, name–face associations of nurses. The overall AMHRU, Kingston Centre, Warrigal Road, Cheltenham, VIC 3192, goal of SR is to enable individuals with memory Australia. Phone: +61-3-9265-1700; Fax: +61-3 9265-1711. Email: [email protected]. Received 4 Dec 2012; revision requested 7 Mar impairment to remember information for clinically 2013; revised version received 24 Jun 2013; accepted 24 Jun 2013. relevant periods of time (e.g. days, weeks, and 2 A. S. Creighton et al. months; Vance and Farr, 2007). SR is administered standard for evaluating clinical interventions) have by first providing the client with a prompt question been conducted on SR training (Davis et al., 2001; and associated target response. When successful Hawley et al., 2008; Lin et al., 2010), with most at recalling the response, the client is required to research lacking a control condition or group and/or actively recall the target information using either utilizing a case study or single-subject design. uniform or increasingly longer inter-trial intervals Nevertheless, all published studies found were (Brush and Camp, 1998a). If at any time the client included in this review for the sake of completeness. is unable to recall the response, they are provided with the information and asked to repeat it (Camp et al., 1996b). Typically, the training is considered Methods successful if the participant correctly responds to the prompt question at the beginning of three consecut- From January to April 2012 (and updated ive sessions (Brush and Camp, 1998a), as long-term in September 2012), a search of PsychINFO, retention of the information has been demonstrated. MEDLINE, and Scopus was performed using At present, little research has been conducted the key terms: “spaced-retrieval,” “memory into the theoretical mechanisms underlying SR training,” “memory rehabilitation,” “cognitive training (Camp et al., 2000). However, Camp training,” “cognitive rehabilitation,” “dementia (2006) suggested that the technique integrates four of the Alzheimer’s type,” “dementia,” and different methods of learning. First, SR is a form “Alzheimer’s/Alzheimer disease.” Reference lists of “ecologically valid priming,” whereby previous of relevant papers were also searched to identify exposure to a stimulus influences later detection and articles that described SR in this population. The identification of that stimulus (Sohlberg and Turk- review was restricted to primary, peer-reviewed stra, 2011). Second, SR is also thought to use “spa- research studies that were published in English and cing effect;” information is learned and retrieved focused on the use of SR training for people with more effectively when trials are distributed over time dementia. rather than mass practiced (Camp et al., 2000). The Using the Australian National Health and utilization of both these methods is thought to be Medical Research Council’s (NHMRC, 2000) particularly beneficial to individuals with dementia, level of evidence hierarchy, all studies reviewed as they capitalize on the relatively spared and auto- were graded according to their design quality. matic implicit memory system (Camp et al., 2000). Specifically, systematic reviews of level II studies Third, SR is regarded as a form of conditioning; were considered to be level I evidence; RCTs were strong associations are formed between the target classified as level II evidence; pseudo RCTs question and response through repetition and suc- were classified as level III-1 evidence; non- cessful recall trials may serve as intrinsic reinforcers randomized experimental trials (including pre- (Camp, 2006). Lastly, SR can also be considered a test–post-test studies), cohort studies, case–control form of errorless learning (e.g. Haslam et al., 2011), studies, and interrupted time series studies with a as it minimizes the possibility of errors during the control group were classified as level III-2 evidence; acquisition phase of learning by ensuring mistakes historical control studies, two or more single arm are repeatedly corrected (Camp et al., 2000). studies, and interrupted time series studies without Interestingly, while SR training appears to be a parallel control group were classified as level III-3 gaining increasing support and attention within evidence; and a case series with either post-test or the field of aged care, to our knowledge only two pre-test–post-test outcomes was classified as level literature reviews have been conducted: one for a IV evidence. French audience only (Erkes et al., 2009) and one by Hopper et al. (2005). As a number of new studies using SR training have been conducted in recent Results years, the purpose of this review was to provide In total, 34 studies were included in this review, an up-to-date overview of this promising technique. with the studies being classified into four types Therefore, this paper describes published research based on the goals of SR training: