Response Inhibition, Stop-Signal Task (ADHD) Children

Abstract The aim of this study was to investigate whether there is a difference in response inhibition measured with the stop signal task between ADHD (n=20) children and ASD (n= 23) children. The stop-signal task measures the ability to interrupt an ongoing response. Evidence from behavioral studies suggest that deficits in response inhibition may be common to several developmental disorders, however it has been suggested to be the core-deficit in ADHD. Children with ADHD have primarily difficulties with sustaining their attention and inhibiting behaviors, whereas ASD children show more deficiencies with flexibility and planning. The results indicate that ADHD children show longer reaction times however this effect did not reach a significant level. Contrary to previous findings ADHD children did not have significantly longer reaction time than ASD children.

Key words: Executive functioning; Attention-Deficit/Hyperactivity Disorder(ADHD); Autism Spectrum Disorder (ASD); Response Inhibition, Stop- Signal task (SSRT)
Introduction
Executive functions are mental control processes that enable goal directed behavior and self control. It has been
According to Barkley's theory of ADHD, an impairment of behavioural inhibition is the foundational deficit of the disorder, and this then affects other executive functions. Several studies reported deficits of especially response inhibition of ADHD children. Response inhibition is a key executive control process that involves the suppression of actions that are inappropriate or no longer required and through this a flexible and goal-directed behavior is established (Barkley, 1997). A study measuring the performance of ADHD children and their relative controls on the Stroop task, found that ADHD patients have significantly more difficulties with response inhibition and longer reaction times (Barkley, Grodzinsky, & DuPaul,