A High Resolution Quantitative EEG Power Analysis of Obsessive-Compulsive Disorder

Introduction: The findings of the quantitative EEG power-spectral studies in obsessive-compulsive disorder (OCD) have so far been mostly inconsistent. Moreover, none of the studies has been a high resolution one. Aim: The aim of the study was to examine the band power of delta, theta, alpha, beta1 and beta2 bands with high resolution EEG data in patients with obsessivecompulsive disorder and compare it with that of normal controls. It was hypothesized that there will be no significant group difference of individual band power between patient and control group. Methods: Raw EEG data were acquired from 64 channels using a linked ear reference. We obtained EEG power values for 20 adult OCD patients (10 males; 10 females) and 19 appropriately matched healthy controls across the abovementioned bands. We used Advanced Source Analysis (ASA, ANT software b.v. Netherlands; version3.0.0.5.) program for analysis of power. Results: OCD patients had significantly higher power in comparison to controls which was widespread in the theta frequency, predominantly left sided fronto-temporo-parietal in delta and alpha and only left frontal in beta2 bands. Conclusion: Increased band power in obsessive-compulsive disorder patients in all these bands which have been shown to be associated with cognitive processing, may reflect increased processing load in this group of patients with recruitment of wide area of cerebral hemisphere (German J Psychiatry 2007; 10: 29-35).