Research RESEARCH BRIEFS

Sluggish Cognitive Tempo: Current Knowledge and Future Directions

by Lisa Jacobson, PhD, NCSP

Do you find yourself saying, “Come on! Hurry up!” multiple times each day? Maybe she is your daughter or he is a student in your classroom. She is the last one to com- plete her work, turn in that test, or even get her things together to go home. Even when he is paying , he just seems to need longer than anyone else to get the job done. Neither child is particularly hyperactive. Could this be ADHD? Something else? in interest in better characterizing the be- almost sixty percent of those with SCT The something else might be sluggish havioral characteristics of sluggish cogni- also met criteria for diagnosis of ADHD cognitive tempo (SCT). A growing body of tive tempo and determining whether and and close to forty percent of those meet- evidence suggests that SCT is a distinct be- to what degree symptoms are distinct from ing the diagnostic symptom threshold for havioral pattern, or phenotype, that is both ADHD and other childhood disorders. ADHD also had SCT. Other studies have overlapping and yet distinct from ADHD similarly found that approximately thirty and other childhood disorders. Identified Measuring SCT symptoms to sixty percent of youth with ADHD inat- during field trials for the fourth edition of SCT symptoms are usually measured with tentive type show high levels of SCT.These the Diagnostic and Statistical Manual of behavior rating scales, typically completed numbers suggest that a large proportion Mental Disorders (DSM-IV), SCT is char- by parents or teachers. Across studies, SCT- of children with SCT would not meet full acterized by a combination of symptoms, related symptoms generally fall into slug- diagnostic criteria for ADHD, and there- such as being slow to complete tasks or gish/sleepy items (appears drowsy, appears fore, may be at risk of being overlooked generally slow-moving, lacking initiative, lethargic, slow-moving or sluggish), day- or underdiagnosed in spite of having true appearing drowsy or sleepy, appearing le- dreamy items (seems to be in his/her own difficulty. It also suggests that conclusions thargic, being easily confused or mentally world, “in a fog,” daydreams), and initiative regarding the impact of SCT on children’s “foggy,” and appearing frequently lost in or persistence items (effort fades quickly, functioning as well as co-occurring symp- thought or “daydreamy.” As the inattentive lacks initiative, appears unmotivated). Re- toms or disorders may differ depending symptoms of ADHD include being easily search suggests that the sluggish/sleepy on whether SCT symptoms are surveyed distracted, difficulty sustaining attention, items are most distinct from both the hy- in children referred for evaluation due to failure to pay close attention to details, peractive-impulsive and inattentive symp- ADHD-related symptomatology or previ- avoidance of tasks requiring sustained toms of ADHD. In fact, data consistently ously diagnosed with ADHD versus mixed effort, etc., it is easy to see that these two show that the three dimensions of SCT have clinical or community samples. groups of symptoms might overlap. a stronger relationship with each other than SCT symptoms also seem to have a real, SCT symptoms do sometimes co-occur with ADHD symptoms with weaker rela- functional impact on children’s behavior with the inattentive symptoms of ADHD, tionships to hyperactive-impulsive symp- and psychosocial competence. Across stud- but are also seen in children that do not toms versus inattentive symptoms. These ies, children with more symptoms of SCT meet formal diagnostic criteria for ADHD. patterns tend to be true for both parent and appear to have a greater tendency to have Perhaps in response to the National Insti- teacher ratings of behavior in children, as internalizing disorders such as or tutes of Mental Health’s recent call for more well as in ratings of adults. , a greater tendency to show dimensional approaches to mental health Recent research found that within a social withdrawal, and decreased social research, there has been a recent increase sample of typically developing children, competence. In contrast to ADHD symp-

32 Attention A growing body of evidence suggests that SCT is a distinct behavioral pattern, or phenotype, that is both overlapping and yet distinct from behavior. Even after considering (statisti- contribute to both organizational and cally controlling for) severity of inatten- homework problems. Using parent ratings, ADHD and other tion symptoms, children with more SCT Russell A. Barkley compared children with symptoms tend to show reduced academic ADHD to those with SCT, ADHD and SCT, childhood disorders. skills, grades/GPA, and overall academic and those who did not meet criteria for ei- progress, including performance in both ther disorder (controls). Interestingly, find- math and reading. ings from this study suggest a fairly con- In one of our studies, we found that the sistent pattern of functional impact, with low initiation/persistence SCT symptoms the amount of difficulty dependent upon in particular appear to show a strong as- severity of children’s symptomatology. Spe- sociation with reports of impairment in cifically, children rated as showing more toms, SCT symptoms seem to be associ- academic progress, even after consider- SCT symptoms were consistently more ated with less externalizing behavior, such ing teacher reports of inattention. Fur- affected in terms of executive functioning as aggression and oppositional defiant thermore, these SCT symptoms seem to and day-to-day impairment than typically ASK THE EXPERT SERIES The Glenholme School Discover fresh ideas and innovative solutions for managing ADHD. Visit Devereux Connecticut chadd.org/AsktheExpert to register today. Providing young people with the foundation needed to lead successful and meaningful lives .

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August 2014 33 developing children, but were less affected alone. Children who show more variable/ depressive symptoms, SCT is also sepa- than children with either ADHD alone or inconsistent responding on reaction time or rable from mood. Core processing speed ADHD plus SCT. The children with both rapid naming tasks seem to perform more may be consistently slowed—and perhaps ADHD and SCT were consistently more poorly on reading fluency tasks, whereas less variable—in SCT relative to ADHD, impaired across almost all outcomes than a pattern of consistently slower response although more research is needed in this children with either disorder alone. speed on both computer-based reaction area. Data regarding genetic heritability time tasks or naming tasks may in fact be for SCT are just beginning to emerge; a Speed of processing associated with better oral reading fluency. recent behavioral genetic study from Italy SCT may also be associated with perfor- This pattern seems particularly true of suggested less heritability for SCT than mance speed on psychological tests. Speed of those children with ADHD, relative to typi- ADHD, but noted that SCT symptoms do processing is a broad term that refers to how cally developing children. Furthermore, in seem to be inherited. Although the name quickly the individual responds to simple a small sample of children selected for be- of the is admittedly less than targets (i.e., reaction time), completes basic low average motor speed, SCT symptoms ideal, and some have advocated chang- fine motor tasks (i.e., timed completion of (particularly the sluggish/sleepy symptoms) ing the name, it is not yet clear how best pencil and paper tasks), or accurately per- predicted their reading fluency on standard- to characterize these symptoms and their forms more complex cognitive tasks (i.e., ized tests of speeded oral reading skills, even most direct functional outcomes in a man- reading fluency). In examining simple re- after their decoding skills and the severity ner that helps support further research, action time, research consistently shows that of ADHD inattention symptoms were tak- identification/differential diagnosis, and children with ADHD are substantially more en into account. Interestingly, in this small intervention. Additional work may help to variable in their responding over time than sample, children with more SCT symptoms better describe the course of SCT symp- typically developing children—but there are seemed to show better performance on the toms during development, clarify the role few data to date examining patterns of reac- reading fluency tests; this may in part re- of sleep and/or sleep disturbance in SCT, tion time in children with SCT. flect a reduction in or improved and identify genetic and neurophysiologi- We suspect that children with SCT may concentration on the task, but needs to be cal markers for the disorder. be more consistently slow and less variable examined further in a larger sample. However, the available research suggests across time, relative to children with ADHD The relation between SCT and perfor- the importance of monitoring children mance speed on psychological tests may with SCT for emergence of mood symp- also vary by age. Examining a sample of toms as they enter adolescence, carefully clinically referred children, we found that screening for co-occurrence of ADHD there was a stronger association between and learning difficulties, and potentially SCT symptoms and motor speed on a providing support for building social skills pencil and paper task for elementary-aged and peer competence. In addition, if the children relative to adolescents. These data preliminary data regarding reading flu- show that younger children with higher ency are further supported, provision of levels of SCT were slower to complete the extended time may facilitate the ability of motor tasks than their peers. The associa- children with SCT to show what they know tion was in the same direction, but much on assignments and tests. With additional weaker, for the older children. research, more targeted interventions will hopefully emerge. ●A Recent press vs. clinical experience and research For a list of studies discussed in this article, please go to chadd.org/SCTReferences . Finally, although some recent press may argue otherwise, both clinical experience Lisa Jacobson, PhD, NCSP, is a licensed and the growing research literature suggest psychologist and pediatric neuropsychologist that SCT exists. The data to date clearly in the department of neuropsychology at the support an association with ADHD pri- Kennedy Krieger Institute in Baltimore. She is marily inattentive type, but further sug- also an instructor in psychiatry and behavioral gest SCT is distinct from ADHD. sciences at the Johns Hopkins University School of Medicine. Her broad research interests include Furthermore, although the sleepy/ examining cognitive and behavioral aspects sluggish and low initiation/per- of neurodevelopmental disorders, specifically sistence SCT symptoms show related to brain-behavior relationships involving some overlap with mood or attention and .

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