Differences in neurophysiological markers of inhibitory and temporal processing deficits in children and adults with ADHD

We compared ADHD-related temporal processing and response inhibition deficits in children and adults using event-related potentials (ERPs) during cued continuous performance tasks (CPT, O-X-version, plus a more demanding flanker version). ERP markers of temporal processing (Cue CNV) and inhibition (NoGo P300) were obtained in matched groups of children (32 with ADHD, mean age 11.2 years, and 31 controls, mean age 11.1 years) and adults (22 ADHD, mean age 42.7 years, and 22 controls, mean age 44.0 years). ERP markers and performance reflected both age and ADHD status. Performance was poorer, and Cue CNV and NoGo P300 were weaker in ADHD children and adults compared to their matched controls. ADHD-related ERP differences in children were more prominent at posterior scalp sites but more pronounced at anterior scalp sites in adults, paralleling the prominent topographic changes of both ERP markers with development. The fact that differences in the same test and the same processing period appear in both children and adults, but that they present in different aspects of performance and different scalp topographies, leads to the conclusion that some ADHD-related deficits persist into adulthood despite alterations of their qualitative aspects