Altered resting-state sensorimotor network in patients with obsessive-compulsive disorder: An EEG study

Dysfunction in the cortical-striatal-thalamo-cortical circuit is considered a core pathological mechanism of obsessive-compulsive disorder (OCD) and may contribute to abnormalities in the sensorimotor network (SMN). Although altered SMN patterns in OCD have been reported using resting-state fMRI, SMN alterations remain underexplored in resting-state EEG (rsEEG). This study aimed to identify frequency-specific SMN alterations in patients with OCD compared to healthy controls (HCs) using rsEEG.

Eyes-closed rsEEG were collected from 41 patients with OCD and 41 HCs. SMN was constructed by eight cortical regions and functional connectivity (FC) with the weighted phase-lag index across six frequency bands. Group differences in FC and strength were assessed using permutation testing. Correlation analysis was conducted between significantly altered measures and Yale-Brown Obsessive Compulsive Scale (Y-BOCS). Machine learning-based classification was applied to assess the potential of SMN features as biomarkers for OCD.

In the theta band, FC between the left primary somatosensory cortex (S1) and the left supplementary motor area was significantly increased in OCD relative to HC. In the high alpha band, FCs between the left S1 and right primary motor cortex (M1), and between the left S1 and right premotor cortex (PMC), as well as local strength in the right PMC, were significantly increased in OCD. FCs between left S1 and right M1 in the high alpha band positively correlated with Y-BOCS. Classification accuracy was achieved at 78.05 %.

These findings suggest that rsEEG-derived SMN alterations may reflect neurophysiological mechanisms of OCD and serve as candidate biomarkers.