Applicability of the Stop-Signal Task for Preschoolers With ADHD.

Inhibitory deficits of children with attention deficit/hyperactivity disorder (ADHD) are well documented. However, the specific inhibition ability (stopping an ongoing response) of preschoolers with ADHD is little reported. This study adopted the tracking stop-signal task to examine preschoolers with ADHD. Twenty-eight children with ADHD (M = 6.1 year, SD = 0.6) were compared to 31 comparison children (M = 6.0 year, SD = 0.6) on a measure of inhibitory control. The results showed that preschool children with ADHD performed worse than their control groups on the stop-signal task, using the omission error index, implying an attention deficit. However, preschool children with ADHD did not exhibit significantly slower stop-signal reaction times relative to the control group. The ability of controlled response inhibition of preschool children may not be mature.