title: Abnormal pitch mismatch negativity in individuals with schizotypal personality disorder.
abstract: BACKGROUND
  The goal of the study was to examine mismatch negativity (MMN) in schizotypal personality disorder (SPD) individuals. Abnormal MMN has been a consistent finding in chronic schizophrenia and there also have been reports of reduced duration MMN in first episode schizophrenia patients [Umbricht, D., Krljes, S., Mismatch negativity in schizophrenia: a meta-analysis. Schizophrenia Research (2005); 76(1):1-23], with some studies finding no pitch MMN amplitude differences [Salisbury, D.F., Shenton, M.E., Griggs, C.B., Bonner-Jackson, A., McCarley, R.W., Mismatch negativity n chronic schizophrenia and first-episode schizophrenia. Archives of General Psychiatry (2002); 59(8):686-694.], while others reporting a modest reduction [Umbricht, D.S., Bates, J.A., Lieberman, J.A., Kane, J.M., Javitt, D.C., Electrophysiological indices of automatic and controlled auditory information processing in first-episode, recent-onset and chronic schizophrenia. Biological Psychiatry (2006); 59(8):762-772], in recent onset schizophrenia patients. To our knowledge no reports exist of MMN in SPD individuals.
  
  
  METHODS
  Twenty six normal (14 females) control and 23 SPD (12 females) individuals were tested using the pitch MMN paradigm. Normal control (NC) and SPD individuals were recruited from the general population and assessed using DSM-IV. SPD individuals were included if they met 5 or more criteria for SPD disorder. The subjects listened to 2000 frequent 1 kHz pure tones and 100 rare 1.2 kHz pure tones while reading a magazine article. MMN was measured from a difference waveform within the latency window of 175-276 ms.
  
  
  RESULTS
  Reduced MMN amplitude was found in SPD relative to NC subjects (p<0.045).
  
  
  CONCLUSIONS
  These results point to potential differences between SPD and schizophrenia, where no reduction in MMN was found in most studies of first episode patients.
authors.affiliation: VA Boston Healthcare System Boston VA Healthcare System, Jamaica Plain VA and Brockton VA campuses, United States. margaret_niznikiewicz@hms.harvard.edu
authors.forename: Margaret A
authors.initials: MA
authors.lastname: Niznikiewicz
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Spencer
authors.forename: Chandlee
authors.initials: C
authors.lastname: Dickey
authors.forename: Martina
authors.initials: M
authors.lastname: Voglmaier
authors.forename: Larry J
authors.initials: LJ
authors.lastname: Seidman
authors.forename: Martha E
authors.initials: ME
authors.lastname: Shenton
authors.forename: Robert W
authors.initials: RW
authors.lastname: McCarley