title: Impaired mismatch negativity generation in prodromal subjects and patients with schizophrenia.
abstract: BACKGROUND
  Mismatch negativity (MMN) specifically the response to tone duration deviants has consistently been shown to be reduced in schizophrenia suggesting dysfunction in auditory sensory memory. As part of a multidimensional approach to the early recognition of psychosis, MMN was investigated as a possible risk factor for later development of psychosis in subjects with a prodromal syndrome. Forty-three prodromal subjects, 31 neuroleptic-free inpatients with schizophrenia and 33 healthy controls were studied. A prodromal state was defined by a cluster 'Cognitive Disturbances' as defined by the 'Bonn Scale for the Assessment of Basic Symptoms' (BSABS), which was found highly predictive of first-episode schizophrenia. To elicit MMN, a three-tone auditory oddball paradigm with 10% 'duration deviants' and 10% 'frequency deviants' was used.
  
  
  RESULTS
  MMN amplitudes to tone duration deviants were significantly reduced in the patients with schizophrenia compared to controls. The putatively prodromal subjects also showed a slight, though non-significant reduction of the MMN amplitude that was intermediate between normal controls and patients with schizophrenia, and with a larger within-group variance.
  
  
  CONCLUSIONS
  These results support the view that abnormalities in temporal processing are particularly pronounced in patients with schizophrenia. Prodromal subjects are a heterogeneous group with regard to outcome and time until transition to a first psychotic episode. Follow-up of these putatively prodromal subjects will show whether MMN amplitudes further reduce over time in those developing psychosis and if a reduction is state-dependent.
authors.affiliation: Department of Psychiatry and Psychotherapy, University of Cologne, Joseph-Stelzmann-Str. 9, D-50924 Cologne, Germany. anke.brockhaus@uni-koeln.de
authors.forename: Anke
authors.initials: A
authors.lastname: Brockhaus-Dumke
authors.forename: Indira
authors.initials: I
authors.lastname: Tendolkar
authors.forename: Ralf
authors.initials: R
authors.lastname: Pukrop
authors.forename: Frauke
authors.initials: F
authors.lastname: Schultze-Lutter
authors.forename: Joachim
authors.initials: J
authors.lastname: Klosterkötter
authors.forename: Stephan
authors.initials: S
authors.lastname: Ruhrmann
mesh_terms: D000161:Acoustic Stimulation; D000328:Adult; D001308:Auditory Perceptual Disorders / Q000175:diagnosis / Q000209:etiology*; D001921:Brain / Q000503:physiopathology*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D004569:Electroencephalography; D004585:Electrooculography; D005260:Female; D006801:Humans; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000209:etiology; D009483:Neuropsychological Tests; D012559:Schizophrenia / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology*; D013998:Time Perception / Q000502:physiology