Executive function in normal aging may be modulated by body habitus and adiposity, both factors modified by physical therapist prescriptions. This study measured between-day reliability of executive function metrics in young and older individuals and examined associations between cognition, adiposity, and physical activity.
Forty-three young and 24 older participants underwent executive function assessment via the National Institutes of Health Toolbox Cognition Battery (Dimensional Change Card Sort, Flanker Inhibitory Control and Attention [Flanker], and List Sorting Working Memory [List Sorting]) at 7-day intervals. Between-day reliability was assessed via intraclass correlation (ICC). Responsiveness was assessed via between-day effect size and Cohen's d. Forward stepwise linear regression examined associations between cognition and age, body mass index, percent body fat, and a self-report measure of physical activity (International Physical Activity Questionnaire Short Form).
Executive function scores were higher for young participants than for older participants (all P< .002), consistent with typical age-related cognitive decline. Reliability of cognitive metrics was higher for older participants (ICC = 0.483-0.917) than for young participants (ICC = 0.386-0.730). Between-day effect sizes were approximately 50% smaller for older participants. Percent body fat significantly correlated with the Flanker Unadjusted Scale (P = .004, R2 = 0.0772). Neither vigorous nor total physical activity correlated with any cognitive metric.
Older participants demonstrated greater between-day reliability for executive function measures, while young participants showed greater capacity to improve performance upon repeat exposure to a cognitive test (especially Flanker). Percent body fat correlated significantly with Flanker scores, while body mass index (an indirect measure of body fat) did not. Self-reported physical activity did not correlate with executive function. Cognitive response to physical therapist-prescribed exercise is a fertile ground for future research.
1Department of Health, Human Function, and Rehabilitation Sciences, The George Washington University, Washington, District of Columbia.
2Department of Neurology, Division of Cerebrovascular Diseases, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung, Taiwan.
3Department of Physical Therapy and Rehabilitation Science, The University of Iowa, Iowa City.
Address correspondence to: Richard K. Shields, PT, PhD, FAPTA, Department of Physical Therapy and Rehabilitation Science, The University of Iowa, 1-252 Medical Education Bldg, Iowa City, IA 52242 (email@example.com).
This study was funded by National Institutes of Health grants R01HD084645 and R01HD082109 to Dr Shields and the National Center for Advancing Translational Sciences Research UL1TR002537 to the University of Iowa.
The authors declare no conflicts of interest.