Staying on Task: Age-Related Changes in the Relationship Between Executive Functioning and Response Time Consistency.
OBJECTIVE
Little is known about the relationship of executive functioning with age-related increases in response time (RT) distribution indices (intraindividual standard deviation [ISD], and ex-Gaussian parameters mu, sigma, tau). The goals of this study were to (a) replicate findings of age-related changes in response time distribution indices during an engaging touch-screen RT task and (b) investigate age-related changes in the relationship between executive functioning and RT distribution indices.


METHODS
Healthy adults (24 young [aged 18-30], 24 young-old [aged 65-74], and 24 old-old [aged 75-85]) completed a touch-screen attention task and a battery of neuropsychological tests. The relationships between RT performance and executive functions were examined with structural equation modeling (SEM).


RESULTS
ISD, mu, and tau, but not sigma, increased with age. SEM revealed tau as the most salient RT index associated with neuropsychological measures of executive functioning. Further analysis demonstrated that correlations between tau and a weighted executive function composite were significant only in the old-old group.


CONCLUSIONS
Our results replicate findings of greater RT inconsistency in older adults and reveal that executive functioning is related to tau in adults aged 75-85. These results support literature identifying tau as a marker of cognitive control, which deteriorates in old age.
Rotman Research Institute, Baycrest, Toronto, Ontario. Department of Psychology, University of Toronto, Ontario.
Brandon P
BP
Vasquez
Rotman Research Institute, Baycrest, Toronto, Ontario. Dalla Lana School of Public Health.
Malcolm A
MA
Binns
Rotman Research Institute, Baycrest, Toronto, Ontario. Department of Psychology, University of Toronto, Ontario. Department of Psychiatry, University of Toronto, Ontario. nanderson@research.baycrest.org.
Nicole D
ND
Anderson
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D056344:Executive Function / Q000502:physiology*; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D008297:Male; D011930:Reaction Time / Q000502:physiology*; D055815:Young Adult
Aging; Ex-Gaussian; Executive functions; Intraindividual variability; Sustained attention.