| The error-related negativity (ERN) is a negative deflection in the event-related potential (ERP), maximal at frontal recording sites approximately 50 after an erroneous response. The differentiation between the ERN and the correct response negativity (CRN) appears to follow a developmental course, becoming stable in mid-adolescence. Unlike the ERN, the error positivity (Pe)---a centrally maximal ERP component that peaks nearly 300 ms after errors---appears relatively stable developmentally. Several studies have reported increased error-related brain activity in patients with obsessive-compulsive disorder (OCD). To date, though, no studies have examined error-related ERPs in pediatric patients with OCD.;A first goal of the present study was to determine whether pediatric patients with OCD would be characterized by increased error-related brain activity. Based on the notion that OCD and trichotillomania (TTM) may both represent OC spectrum disorders, the present study also evaluated error-related brain activity in pediatric TTM patients. Finally, error-related brain activity was recorded in these OCD and TTM patients both before and after cognitive-behavioral therapy (CBT) to examine the relationship between symptom severity and ERP measures of response monitoring.;To this end, the electroencephalogram was recorded from 22 pediatric OCD patients, 18 pediatric TTM patients, and 19 age-matched control participants who performed a speeded response task; of these participants, 10 OCD and 9 TTM patients returned for a second testing session following cognitive behavioral therapy; 13 control subjects also returned for a second testing session.;Consistent with previous studies, the ERN was reliably larger than the CRN, but only in older participants (greater than 13 years of age). Additionally, the present study found that the ERN was reliably larger than the CRN in both the OCD and TTM patients, but not in the control group; this difference emerged only when both the pre- and post-treatment data was analyzed. The ERN and CRN did not change across testing session. The Pe did not vary as a function of age or diagnostic status. Together, these data suggest that an accelerated differentiation between the ERN and CRN may represent a vulnerability factor for the development of OC disorders such as OCD and TTM. |
