Schizophrenia and evoked potentials: maximum amplitude, frequency of peaks, variability, and phenothiazine effects.

The purpose of this study was to compare averaged visual evoked potentials AVEPs) in normal subjects and in schizophrenics off and on phenothiazine medication. Flashes of 4 intensities were used. Ss were tested 3 times within a 1 month period. Measures of maximum amplitude (Am), frequency of peaks I FOP), and variability (V) were obtained- With increases in stimulus intensity all Ss showed increases in Ams and decreases in FOPs and V. Schizophrenics had smaller Ams. greater FOPs, and grear V than normals. Schizoprenies on phenothiazines generally had less FOPs initially and after 1 wk mi medication but not after about I month on medication. There was no consistently significant effect of phenothiazines on maximum amplitude. NO drug effect on variability was observed. Schizophrenics showed a decrease in FOPs over time while normals showed an increase. A relationship was found between variability and overall thought disturbance. Changes in clinical condition over a month were not associated with discernible AVEP changes. Relationships between Am, FOP, unit V are presented.

[1]  J. Stevens.  An anatomy of schizophrenia? , 1973, Archives of general psychiatry.

[2]  J. C. Corby,et al.  The effect of predictability on evoked response enhancement in intramodal selective attention. , 1973, Psychophysiology.

[3]  M. Buchsbaum,et al.  The effects of attention, stimulus intensity, and individual differences on the average evoked response. , 1973, Psychophysiology.

[4]  E Callaway,et al.  Evoked potential variability: effects of age, amplitude and methods of measurement. , 1973, Electroencephalography and clinical neurophysiology.

[5]  W. Roth,et al.  Some features of the auditory evoked response in schizophrenics. , 1972, Archives of general psychiatry.

[6]  R T Wilkinson,et al.  Auditory evoked potentials and selective attention. , 1972, Electroencephalography and clinical neurophysiology.

[7]  E R John,et al.  Switchboard versus statistical theories of learning and memory. , 1972, Science.

[8]  B Saletu,et al.  Auditory evoked response, EEG, and thought process in schizophrenics. , 1971, The American journal of psychiatry.

[9]  E Callaway,et al.  Auditory evoked potential variability in schizophrenia. , 1970, Electroencephalography and clinical neurophysiology.

[10]  E. Callaway,et al.  Auditory evoked responses in schizophrenia--a reassessment. , 1970, Biological psychiatry.

[11]  L Cigánek,et al.  Binocular addition of the visually evoked response with different stimulus intensities in man. , 1970, Vision research.

[12]  B. Kopell,et al.  The effects of stimulus differences, light intensity, and selective attention on the amplitude of the visual averaged evoked potential in man. , 1969, Electroencephalography and clinical neurophysiology.

[13]  M. Rappaport.  ATTENTION TO COMPETING VOICE MESSAGES BY NONACUTE SCHIZOPHRENIC PATIENTS: EFFECTS OF MESSAGE LOAD, DRUGS, DOSAGE LEVELS AND PATIENT BACKGROUND , 1968, The Journal of nervous and mental disease.

[14]  G. Heninger,et al.  Visual Evoked Responses and Mental Status of Schizophrenics: During and After Phenothiazine Therapy , 1966 .

[15]  L. Speck,et al.  Visual evoked responses of psychiatric patients. , 1966, Archives of general psychiatry.

[16]  C. Shagass,et al.  Some psychologic correlates of cerebral responses evoked by light flash. , 1965, Journal of psychosomatic research.

[17]  E. Callaway,et al.  THE AUDITORY EVOKED RESPONSE AS A DIAGNOSTIC AND PROGNOSTIC MEASURE IN SCHIZOPHRENIA , 1965 .

[18]  D. Lindsley,et al.  Selective Attentiveness and Cortical Evoked Responses to Visual and Auditory Stimuli , 1965, Science.

[19]  D. Lindsley,et al.  Attention, Vigilance, and Cortical Evoked-Potentials in Humans , 1964, Science.

[20]  W. Cobb,et al.  The latency and form in man of the occipital potentials evoked by bright flashes , 1960, The Journal of physiology.

[21]  P. Venables,et al.  A short scale for rating paranoid schizophrenia. , 1959, The Journal of mental science.

[22]  L. Ciganek.  The effect of largactil on the electroencephalographic response evoked potential to light stimulus in man. , 1959, Electroencephalography and clinical neurophysiology.

[23]  L. Goodman,et al.  THE PHARMACOLOGICAL BASIS OF THERAPEUTICS , 1966 .

[24]  M Rappaport,et al.  Peak identification in visual evoked potentials. , 1973, Psychophysiology.

[25]  J. Gottlieb,et al.  [Some electrographic differences between chronic schizophrenic patients and normal subjects]. , 1968, Recent advances in biological psychiatry.

[26]  F. K. Redding.  Modification of sensory cortical evoked potentials by hippocampal stimulation. , 1967, Electroencephalography and clinical neurophysiology.

[27]  D. Shakow,et al.  Segmental set. , 1962, Archives of general psychiatry.