Multifocal visual-evoked potentials in patients with schizophrenia during treatment

Aim: Investigation of responses of multifocal visual-evoked potentials (mfVEPs) in schizophrenic patients under treatment in whom no abnormality was detected on the conventional perimetry. Methods: Recordings of mfVEPs were performed in 31 schizophrenic patients and 30 normal subjects using a VERIS Junior Science recording apparatus (Mayo, Aichi, Japan). Responses from eight sites in each subject were divided into four quadrants (superior and inferior temporal quadrants, and superior and inferior nasal quadrants). In each quadrant, two response waves were grouped and averaged, and the latency and amplitude of main waveforms that appeared near 100 ms were evaluated. Results: The peak latency was about 7-9 ms prolonged and the amplitude was reduced by about 2-5 nV/deg2 in the schizophrenic patient group compared to those in the normal subject group, and significant differences were noted in both parameters in all quadrants. Conclusion: In schizophrenic patients under treatment with psychotropic agents, prolongation of the latency and amplitude reduction were noted in mfVEPs even though no abnormality was detected on the conventional perimetry.