EEG source analysis in obsessive-compulsive disorder

Abstract

Objective: The goal of this study was to assess the activity of intracortical EEG sources in patients with OCD.

Methods: We compared resting state EEG from 50 OCD patients and 50 matched controls using standardized low-resolution electromagnetic tomography (sLORETA) and normative independent component analysis (NICA). Data were analyzed with 1 Hz frequency resolution. Group ICA was used to separate seven independent components from the control group data. The resulting weights and norms served to derive the same components from the OCD group and to compare their power with controls.

Results: In OCD, sLORETA indicated low-frequency power excess (2-6 Hz) in the medial frontal cortex, whereas group ICA showed increased low-frequency power in a component reflecting the activity of subgenual anterior cingulate, adjacent limbic structures and to a lesser extent also of lateral frontal cortex.

Conclusions: Both methods provided evidence for medial frontal hyperactivation in OCD.

Significance: Our study is the first to use normative ICA in a clinical sample and indicates its potential utility as a diagnostic tool. The findings provide consistent results based on EEG source localization in OCD and are of practical interest for therapeutic interventions.