Are abnormal event-related potentials specific to children with ADHD? A comparison with two clinical groups.

Children with attention deficit disorder and hyperactivity (ADHD) were compared with two other clinical groups, namely, children with autism and children with dyslexia, with respect to several peaks of the ERP. By using these other clinical groups, it was studied whether amplitude differences between children and ADHD and normal control children, which were found in an earlier study, were specific to children with ADHD. ERPs were measured in response to stimuli in an auditory and a visual oddball task. Only with respect to the P3 and Pz, measured in response to deviant auditory stimuli, did the children with ADHD show smaller amplitudes than both autistic children and those with dyslexia. It was concluded that a smaller amplitude of this peak is specific to children with ADHD.