title: Event-related potentials in schizophrenia during tonal and phonetic oddball tasks: relations to diagnostic subtype, symptom features and verbal memory.
abstract: BACKGROUND
  This study compares event-related potentials for paranoid patients (n = 13) versus matched undifferentiated patients and unmedicated patients (n = 14) versus matched healthy adults.
  
  
  METHODS
  Event-related potentials of right-handed patients and control subjects were recorded from 30 electrodes during oddball tasks using consonant-vowel syllables or complex tones. Patients were also assessed using the Positive and Negative Syndrome Scale, the Thought Disorder Index, and the Wechsler Memory Scale.
  
  
  RESULTS
  Paranoid patients did not differ from undifferentiated patients in N1 or P3 amplitude but showed larger N2 at frontocentral sites to phonetic stimuli, as well as larger N2 over left than right hemisphere. Unmedicated patients showed reduced N2, but not N1 or P3, compared to control subjects.
  
  
  CONCLUSIONS
  The N2 findings are consistent with neuropsychological evidence of greater verbal abilities and left hemisphere dominance in paranoid than nonparanoid schizophrenia. The findings also confirm the relationship of P3 to total Brief Psychiatric Rating Scale score, negative symptoms, and verbal associative memory.
authors.affiliation: Department of Psychiatry, Columbia University College of Physicians and Surgeons, New York, NY, USA.
authors.forename: G E
authors.initials: GE
authors.lastname: Bruder
authors.forename: J
authors.initials: J
authors.lastname: Kayser
authors.forename: C E
authors.initials: CE
authors.lastname: Tenke
authors.forename: M
authors.initials: M
authors.lastname: Friedman
authors.forename: D
authors.initials: D
authors.lastname: Malaspina
authors.forename: J M
authors.initials: JM
authors.lastname: Gorman
mesh_terms: D000328:Adult; D001921:Brain / Q000503:physiopathology; D010054:Brief Psychiatric Rating Scale; D003937:Diagnosis, Differential; D005072:Evoked Potentials, Auditory / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000150:complications / Q000175:diagnosis*; D010700:Phonetics; D012563:Schizophrenia, Paranoid / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology*; D014825:Vocabulary; D014888:Wechsler Scales