Auditory evoked potentials and total sleep deprivation in depressed patients

Cortical auditory evoked potentials (latencies N1 and P2, N1-P2 amplitude, and amplitude/stimulus intensity function) were studied before and after 1 night's total sleep deprivation in 20 drug-free depressed inpatients. Responders to sleep deprivation showed an augmenting pattern on the non-dominant hemisphere and a reducing pattern on the dominant hemisphere. The interhemispheric difference in auditory cortex was also apparent in the group of patients who failed to respond to sleep deprivation, but with values pointing in the opposite direction. The augmenting pattern shown by responders in the nondominant hemisphere may be a predictor of therapeutic response to sleep deprivation and to subsequent treatment with drugs influencing serotonergic pathways.