P50 ABNORMALITIES IN SCHIZOPHRENIA - RELATIONSHIP TO CLINICAL AND NEUROPSYCHOLOGICAL INDEXES OF ATTENTION

While the P50 component (50-60-ms latency) of the auditory evoked pote ntial has been reported as abnormal in schizophrenia, few studies have examined the relationship between this abnormality and clinical or ne uropsychological measures. To examine these possible relationships, mi d-latency auditory evoked potentials were recorded at the CZ recording site of 47 patients with schizophrenia in response to binaural clicks presented at three stimulus rates: 1, 5 and 10/sec. A sub-sample of p atients were then divided into high- (n=15) and low-P50 abnormality (n =16) groups based on a median split of the P50 amplitude at a rate of 10/sec (a greater amplitude at this rate suggests a greater abnormalit y in recovery) of the entire sample. Only those patients with complete neuropsychological and clinical data and who were reasonably matched on demographic dimensions were included. A multivariate analysis of va riance of 11 neuropsychological function profile scores showed a signi ficant group x global score interaction (Hotelling t=3.97, p<0.005). T he high-abnormality group had relatively greater deficits for attentio n profile scores than for the remaining neuropsychological measures. A n analysis of global subscores for SAPS and SANS clinical measures rev ealed a significant difference only for the SANS attention subscale (p < 0.05). The high-abnormality group was rated as more severe on the a ttention measure. These convergent findings across both phenomenologic al and neuropsychological measures suggest that abnormalities in P50 r ecovery may be linked to deficits in attention processes in schizophre nia. (C) 1998 Elsevier Science B.V. All rights reserved.