Corollary discharge dysfunction in auditory verbal hallucinations: N100 suppression measured with semi-dry electrodes

Corollary discharge dysfunction in patients with auditory verbal hallucinations (AVH) is reflected in failure to attenuate the N100 event-related potential. Previous research has shown mixed findings regarding N100 suppression and hallucination severity, generally using broad symptom scales rather than AVH-specific measures. This study investigated corollary discharge and its relationship with comprehensively characterized auditory hallucinations.

Corollary discharge was investigated in 14 patients with persistent auditory hallucinations and 15 healthy controls using an EEG paradigm using semi-dry electrodes where participants self-generated sounds in a "talk" condition and listened to playback in a "listen" condition. N100 suppression was calculated as the peak-amplitude difference (μV) between talk and listen in the 60-150 ms window. Auditory hallucinations were assessed with the Psychotic Symptom Rating Scales Auditory Hallucination Subscale (PSYRATS-AHS).

Between-group analysis of the fronto-central ROI (Fz-Cz) showed a statistically non-significant trend toward greater N100 suppression in healthy controls compared to AVH patients (p = 0.095, Cohen's d = 0.64). N100 suppression showed significant negative correlation with hallucination severity in the AVH group (r = -0.54, p = 0.047).

Hallucination severity is related to impaired corollary discharge mechanisms, supporting its role as a mechanistic basis for auditory hallucinations.

The preliminary correlation with PSYRATS-AHS suggests potential value in using symptom-specific assessment tools in research on auditory hallucinations, warranting replication in larger samples.