Prefrontal and Parietal Deficits in ADHD Suggested by Brain Electrical Activity Mapping During Children's Performance of the AX CPT

Abstract

AbstractNine children meeting DSM-III-R criteria for Attention Deficit Hyperactivity Disorder (ADHD) and eighteen normal children participated in this study. A screening assessment revealed significantly more behavioural and academic problems in the ADHD group. Subjects performed a low demand visual vigilance task (the reference task) and the AX version of the continuous perfonnance task (CPT), while the steady-state visually evoked potential (SSVEP) was continuously recorded from 64 scalp electrode sites. The topography of the SSVEP amplitude difference between the reference and AX tasks was examined. In the 3.5 second interval between the appearances of the “A” and the “X” normal children showed transient reductions in right prefrontal SSVEP amplitude and a sustained reduction in right parieto-occipital SSVEP amplitude. These reductions in SSVEP amplitude were not seen in ADHD subjects. These results suggest that the presentation of a priming stimulus is associated with increased activation of right prefrontal and parieto-occipital regions in normal children, whereas the absence of this pattern of activation suggests a deficit in these processes in ADHD.