Schizophrenia is a chronic, debilitating major mental illness which neural correlates remain unknown. Recently, the topographic brain maping of P300 has been applied to examine the psychophysiological disturbance in schizophrenics, particulary
with
regard to the topographic distribution of P300. The most robust and consistently replicated electrophysiological abnormalities in schizophrenics involve the auditory P300 event related potential(ERP), a positive potential that begins
approximately
300
msec following a target stimulus that is novel and task-relevant. Reduction in amplitude of auditory P300 ERP has been related to cognitive deficits, brain structure abnormalities, chemical abnormalities, and clinical status.
Auditory P300 ERP has been extensively examined in psychiatric research, and many investigators have saught their psychophysiological meanings and clinical significances since the recording procedure of P300 was standardized.
On the basis of these aspects, this study was designed to evaluate not only the shape, latency and amplitude of P300, but also the topographic distribution in schizophrenics before and after antipsychotic treatment and to examine the availability
of the
characteristic findings of P300 mapping as one of the biological markers.
The subjects were consisted of 26 schizophrenics who had been admitted to Kangnam St. Mary's Hospital and Our Lady of Mercy Hospital, Catholic University Medical College from February, 1993 to September, 1994.
@ES The results were as follows:
@EN 1) Shape of P300 in schizophrenics before and after treatment was inverted U type, but that of controls was inverted V type.
Latency of P300 in schizophrenics before treatment was 354 msec, which was more prolonged than in controls(331 msec). Latency of P300 in schizophrenics after treatment was 339msec, which was not significantly different with controls(331 msec).
2) There were significant differences of topographic amplitudes of P300 between schizophrenics before treatment and controls in the mid-centroparietal, left and right centroparietal, left temporal areas.
3) There were significant differences of topographic amplitudes of P300 between schizophrenics after treatment and controls in the mid-centroparietal, right central, left and right parietal areas. Differences of latencies between schizophrenics
before
and after treatment were not significant.
4) There were significant differences of topographic amplitudes of P300 between schizophrenics before and treatment in the mid-central, mid-parietal and left temporal areas.
5) The score of brief psychiatric rating scale(BPRS) in schizophrenics before treatment was 44.86±10.51, after treatment was 34.18±8.62 respectively. There were significant differences between them.
The finding of minimal changes in auditory P300 amplitude in mid-central, mid-parietal, right central, left and right parietal areas were not affected by treatment. Therefore, it was suggested that reduced P300 amplitude of schizophrenics before
treatment in mid-centroparietal and left temporal area were affected by treatment.
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