M.G.Paule1, R.L.Baldwin2, R.A.Flake2, D.J.Blake2, M.C.Edwards2, C.R.Feild2, J.B.Meaux2, J.J.Chelonis2, 1NCTR, FDA, Jefferson, AR, 2Arkansas Children's Hospital, Little Rock, AR
An automated system was used in children (n = 720) 5 to 13 years old to quantitate time estimation performance. The temporal response differentiation (TRD) task required subjects to hold a response lever down for at least 10 but no more than 14 seconds. Nickels were delivered for each correct response. Evidence of timing ability (a peak in the percentage of lever holds occurring in the reinforced window of ~30%) was noted in children as young as 6 years old, after which correct responding increased with age to ~65% at age 13. There were no sex differences in TRD task performance. Children with higher IQ scores made more correct lever holds. The performance of young children with below average IQ was more variable than that of children with above average IQ. For children with ADHD (n =17), TRD task performance improved significantly when they were tested within 2 hr of taking their prescribed dose of methylphenidate (MPH). Percent lever holds between 10 and 12 sec increased; % short (2-4 sec) lever holds, % burst responses (rapid lever presses) and response variability decreased. These data demonstrate that the TRD task provides useful measures of cognitive function in children and that MPH enhances timing precision in children with ADHD. (Supported by NCTR and Arkansas Children’s Hospital)