Signal-to-noise Ratio and Response Variability in Affective Disorders and Schizophrenia
Schizophrenic patients tend to have smaller and apparently more variable evoked potentials (EPs) than normal controls. The amplitude abnormality is consistent with a number of psychological theories of schizophrenia (e.g. Freud, Pavlov, Venables, Broen and Storms, Silverman) characterized by Epstein and Coleman (1970) as assuming that the “basic deficit in schizophrenia consists of a low threshold for disorganization under increasing stimulus input.” While it is difficult to compare specific components in recordings made from different laboratories, there is general agreement that the P100-N140-P200 complex is smaller in schizophrenics, regardless of sensory modality (see review by Buchsbaum, 1977). As predicted by the various theories, reduction in amplitude is particularly marked for high levels of stimulation such as rapid rates of stimulus presentation, high intensity (Landau, 1975; Rappaport, 1975), novel (Roth and Cannon, 1972) or paired stimuli (Shagass, 1976).
KeywordsResponse Variability Research Diagnostic Criterion Average Evoke Response Evoke Brain Potential Research Diagnostic Criterion
Unable to display preview. Download preview PDF.
- 3.Buchsbaum, M.S., Average evoked response and stimulus intensity in identical and fraternal twins. Physiological Psychology 2: 365–370, 1974Google Scholar
- 4.Buchsbaum, M.S., Self-regulation of stimulus intensity: augmenting/reducing and the average evoked response, in: Consciousness and Self Regulation. (Eds) Schwartz, G.E. and Shapiro, D. Plenum Press, New York, 1976, pp. 101–135Google Scholar
- 5.Buchsbaum, M.S., The middle evoked response components and schizophrenia. Schizophrenia Bull. 3: 93–104, 1977Google Scholar
- 6.Callaway, E., Brain Electrical Potentials and Individual Psychological Differences. Grune & Stratton, New York, San Francisco, London, 1975Google Scholar
- 7.Cohen, R., The influence of task-relevant stimulus variations on the reliability of auditory evoked responses in schizophrenia, in: Average Evoked Responses and Their Conditioning in Normal Subjects and Psychiatric Patients. (Eds.) A. Fessard and G. Lelord, Inserm, Paris, 1973, pp. 373–388.Google Scholar
- 8.Coppola, R., A table driven system for stimulus-response experiments. Proc. of the Digital Equipment Users Soc., 1977.Google Scholar
- 13.Jones, R.T., Blacker, K.H., Callaway, E. and Layne R.S., The auditory evoked response as a diagnostic and prognostic measure in schizophrenia. Am. J. Psychiatry 122: 33–41, 1965Google Scholar
- 16.Lifshitz, K., Intra and inter individual variability and the averaged evoked potential in normal and chronic schizophrenic subjects. Electroenceph. Clin. Neurophysiol. 27: 686–689, 1969.Google Scholar
- 17.Otnes, R.K. and Enochson, L. Distal Time Series Analysis. John Wiley, New York, 1972Google Scholar
- 21.Saletu, B., Saletu, M. and Itil, T.M., The relationships between psychopathology and evoked responses before, during, and after psychotropic drug treatment. Biol. Psychiatry 6: 46–74, 1973Google Scholar
- 26.Spitzer, R.L., Endicott, J.E. and Robins, E., Research Diagnostic Criteria (RDC) for Selected Group of Functional Disorders. New York, Biometrics Research, New York State Psychiatric Inst., 1975.Google Scholar
- 27.Zerlin, S. and Davis, H., The variability of single evoked vertex potentials in man. Electroencephalogr. Clin. Neurophysiol. 23: 467–474, 1967Google Scholar