Impairment of Executive Functions in Boys with Attention Deficit/Hyperactivity Disorder

The main aim of the present study is to compare the efficiency of executive control processes in 24 boys with attention deficit/hyperactivity disorder (ADHD) and 58 normal controls of similar age (between 8 and 11 years). Three reaction time (RT) paradigms were utilized: a dual task that requires coordination of two tasks responses, a shift task that makes it necessary to disengage attention from one task and engage into another one, and a stimulus-response spatial compatibility task that requires participants to inhibit a prepotent response. Another purpose of the study is to examine whether Barkley’s (1997) Barkley, R. A. 1997. “ADHD and the nature of self-control”. New York: Guilford Press. [Google Scholar] executive dysfunction or Sergeant et al.’s (1999) Sergeant, J. A., Oosterlaan, J. and van der Meere, J. J. 1999. “Information processing and energetic factors in attention-deficit/hyperactivity disorder”. In Handbook of Disruptive Behavior Disorders, Edited by: Quay, H. C. and Hogan, A. 75–104. New York: Plenum Press. [Crossref] , [Google Scholar] resource allocation/arousal model best account for the behavioral deficits associated with ADHD. Examination of raw RT data showed significantly poorer performance in ADHD children with respect to age-matched controls on both the higher-level cognitive functions of executive control and on lower-level abilities (e.g., speed of processing) of all tasks of this study. However, using proportional transformations of raw RT data, we could demonstrate that, in addition to differences in processing speed, also executive control processes were significantly impaired in children with ADHD.