Auditory Evoked Potential (AEP) in schizophrenia

This AEP study aims to investigate the characteristics of cerebral responsiveness in a large number of 181 schizophrenics compared with 200 normal controls. AEPs evoked by binaural click stimuli were recorded with 1024 msec of analysis time through the two derivations (3 CH: Cz→A1+2, 6 CH: Cz→T5). The differences between the two groups of each sex in latency and interpeak amplitude were estimated statistically. The statistically significant (P<0.01 or 0.05) results were obtained as follows. 1. The schizophrenic group of both sexes showed a significant latency prolongation, middle latency components, P 2, P 3, long latency components, especially for the most prominent negative peak N 4 and prominent positive peak P 5. 2. The schizophrenic group of both sexes showed a significant interpeak amplitude reduction including the most prominent negative peak N 4 and prominent positive peak P 5, but augmentation for N 2-P 3. 3. There were no significant differences in latency and amplitude of N 4, P 5 between unmedicated and medicated schizophrenics. A few components with significant differences in latencies and amplitudes between the subjects taking antipsychotics more than 600 mg, in chlorpromazine equivalent values, or not, coincides with those also between the epileptics and healthy subjects. Theses differences in the middle and long latency components confirmed regardless of schizphrenic subtypes, suggests the dysfunction in the primary and secondary cortex in schizphrenics

An application of wavelet analysis to the human cerebral evoked potential

Adopting Wavelet analysis for the analysis of the waveform of EP (Evoked Potential), it was intended to confirm possibility of the subjective diagnosis for schizophrenia, epilepsy and healthy subject. 1. Each waveform of EPs (SEP, VEP and AEP) of 100 healthy male subjects (25.4±3.1 y.o.), 100 male schizophrenics (31.6± 10.4 y.o.) and 99 male epileptics (35.9± 13.1 y.o.) were subjected to the Wavelet analysis and the multiresolution analysis. As a result, the difference of Wavelet values among these subject groups were verified significantly. The Wavelet values was defined as the square means of each wavelet coefficients at each scale of multiresolution analysis. 2. The waveform of EPs of each subject were discriminated by use of discriminant method derived from Wavelet Function, in order to judge to which subject group the subject belongs, according to the wavelet values. Analyzing the waveform of EP, between 15~600msec of latency, the highest value of sensitivity, 89%, 87% and 88% was obtained for normal subject, schizophrenics and epileptics, respectively. As the conclusion, the possibility of the subjective diagnosis for schizophrenia, epilepsy, and normal subjects, by Wavelet analysis of EP waveform, were verified possible