Task Demand in Schizophrenia: Auditory Multichannel ERPs
Jürgen Kayser, Gerard E. Bruder, Craig E. Tenke
Department of Biopsychology, New York State Psychiatric Institute, New York, NY 10032, USA
Abstract
Objective: Study the influence of cognitive demand on abnormal auditory processing in schizophrenia.
Method: Using complex tones or consonant-vowel syllables, multichannel ERPs were recorded during simple target detection ("oddball") and more challenging dichotic listening tasks from 26 schizophrenic patients and 26 healthy adults.1,2
Results: Task demand was reflected in the N2-P3 complex (oddball largest) and the late positive complex (dichotic largest). Controls showed 1) stimulus-dependent N2 asymmetries, particularly for oddball tasks, with larger N2 over right temporal sites for complex tones, and over left parietal sites for syllables; and 2) N2 differences as a function of task demand. Patients had reduced N2 and failed to show either of these effects, but showed enhanced P3 amplitude in the simple tonal task. Patients' reductions of late positive slow wave were independent of stimulus type and cognitive demand.
Conclusions: Whenever possible, patients may compensate for early processing deficits (N2) with more effortful later processing (P3).
References:
1 Kayser, J., Tenke, C.E., Bruder, G.E., 1998. Dissociation of brain ERP topographies for tonal and phonetic oddball tasks. Psychophysiology, 35, 576-590.
2 Bruder, G., Kayser, J., Tenke, C., et al., 1999. Left temporal lobe dysfunction in schizophrenia: event-related potential and behavioral evidence from phonetic and tonal dichotic listening tasks. Arch. Gen. Psychiatry, 56, 267-276.