Subcortical functioning in obsessive-compulsive disorder: An exploratory EEG coherence study

Abstract

Background. Given the paucity of quantitative EEG studies using coherence measures to understand the electrophysiological functional integrity of sub-cortical structures in obsessive-compulsive disorder, the current study was carried out. Methods. We obtained EEG coherence values for 20 adult OCD patients (10 males; 10 females) and 19 appropriately matched healthy controls across delta (0.5–3.5 Hz), theta (4–7.5 Hz), alpha (8–12 Hz), beta1 (12.5–20 Hz) and beta2 (20.5–30 Hz) bands. As coherence between distant brain regions reflects physiological activities at sub-cortical neural networks, we chose EEG channels at four distant brain regions – anterior interhemispheric, posterior interhemispheric, fronto-temporal and fronto-occipital. Results. In comparison to controls we found significant increase of theta band EEG coherence in the fronto-occipital region in OCD patients (P = 0.045) which did not correlate significantly with either medication status or disease severity. Conclusion. This EEG coherence study that suggests hyperactivity at subcortical circuitry in OCD patients is in agreement with existing neuro-imaging findings. Furthermore, this finding provides external validity for sub-cortical dysfunction hypothesis of OCD.