Exploration of auditory P50 gating in schizophrenia by way of difference waves

Arnfred, S. M.
Department of Psychiatry, Universityhospital of Copenhagen, Denmark
E-mail: s.arnfred@tdcadsl.dk

The hypothesis of a sensory gating defect in schizophrenia has been supported by studies demonstrating deficient auditory P50 gating in the patients. P50 gating is the relative attenuation of P50 amplitude in the auditory evoked potential following the second click stimulus in a stimulus pair.

Difference waves have mostly been employed in studies of later event related potentials but here the method is applied exploratory on auditory P50 gating data of un-medicated schizophrenia spectrum patients (n=17) and healthy controls (n=24).

The patients had an attenuated difference P50. This attenuation was primarily seen in the sub-sample of patients with severe negative symptoms.

The low frequency difference waveform uncovered abnormalities, which cannot entirely be understood within the sensory gating theory.