Electrophysiological sleep features and inhibitory control functions in patients with obsessive-compulsive disorder

This study aims to explore differences in sleep electrophysiological characteristics between obsessive-compulsive disorder (OCD) patients and healthy controls (HCs), as well as their relationship with inhibition control dysfunction and obsessive-compulsive symptoms.

Polysomnography (PSG) was performed on 24 OCD patients (13 males and 11 females; mean age = 27.63 ± 8.28 years) and 21 HCs (10 males and 11 female; mean age = 28.95 ± 8.77 years) and N2 stage sleep EEG data were extracted for spectral analysis across all frequency bands and spindle feature analysis. Power spectral density (PSD) was estimated using Welch's periodogram method. Spindle features were detected by the Spindler algorithm. The Flanker task was used to measure inhibitory control function. The clinical characteristics of the two groups were assessed using the Y-BOCS, HAMD, HAMA, and PSQI scales.

Compared with HCs, OCD patients showed significantly reduced power in the low-frequency bands in the frontal, central and occipital regions (Delta and Theta, P < 0.05), while power in the high-frequency bands (Beta1 and Beta2, P < 0.01) was significantly increased. Additionally, the OCD patient group exhibited significantly higher spindle frequencies at frontal (F3: F = 13.927, P = 0.002; F4: F = 10.116, P = 0.006) and central electrodes (C3: F = 14.780, P = 0.002; C4: F = 10.723, P = 0.006), as well as higher slow spindle frequencies at frontal (F3: F = 9.285, P = 0.016; F4: F = 9.598, P = 0.016) lobe electrodes. Significant positive correlations were observed between higher F3 (β = 0.270, P < 0.05), C3 (β = 0.192, P < 0.05), and C4 (β = 0.180, P < 0.05) spindle frequencies in the OCD group and longer inconsistent reaction times. Simultaneously, slow spindle density at F4 exhibited a significant positive correlation with Obsession scores in patients (F4: r = 0.606, P < 0.05).

Patients with OCD exhibit reduced low-frequency power and increased high-frequency power and sleep spindle frequency. Increased spindle frequency is positively correlated with poorer inhibitory control function. The above findings suggest that sleep electrophysiological characteristics may be one of the key neural bases of abnormal inhibitory control regulation in OCD patients.