Visual Evoked Potential (VEP) in schizophrenics
Okura, Masao The University of Tokushima
Ikuta, Takumi The University of Tokushima
Tada, Kazuyuki The University of Tokushima
Okada, Ken The University of Tokushima
Furuta, Noriko The University of Tokushima
Nakayama, Hiroshi The University of Tokushima
Yamanishi, Kazunari The University of Tokushima
visual evoked potentials
The differences between schizophrenics and healthy subjects in Visual evoked potential (VEP) were studied with 174 schizophrenics (98 male and 76 female) and 200 healthy subjects (100 male and 100 female). VEPs evoked by flash stimuli were recorded through the two derivations (monopolar: O1→A1+2; bipolar: O1→Cz), averaging 100 responses, with 1024 msec of analysis time. Individual VEPs were subjected to the component analysis, and the following statistically significant results were obtained.
1. In schizophrenics, the latencies in short-latency components were significantly longer in P2 (male, monopolar), N2, P3, N3 (male, bipolar) and N3 (female, monopolar). Those in middle-latency components were significantly shorter in P4~N5 (male, monopolar) and P6 (female).
2. The inter-peak amplitudes in short-latency components were significantly smaller in P3-N3 (male, mopolar), and larger in P1-N1, N1-P2, P2-N2 (male, bipolar). Those in middle-latency components were significantly smaller in N3-P4 (male, monopolar), and larger in N4-P5 (female, bipolar).
3. A few components with significant differences in latencies and interpeak amplitudes between the subjects taking neuroleptics more than 600 mg, in chlorpromazine equivalent values, or not, as well as between medicated and unmedicated subjects, coincided with those also between the schizophrenics and healthy subjects.
Theses differences in VEPs confirmed in the present study, regardless of schizophrenic subtypes, suggest the dysfunction in visual information processing in schizophrenics, and VEP abnormalities may serve as possible elctrophysiological indices for cognitive dysfunction in schizophrenics.
Shikoku Acta Medica
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