title: Progressive reduction of visual P300 amplitude in patients with first-episode schizophrenia: an ERP study.
abstract: OBJECTIVE
  To understand the underlying dynamic neurophysiological changes over the course of schizophrenia, it is important to study subjects longitudinally from the early stage of the illness. We previously reported that visual P300 was already impaired in patients with first-episode schizophrenia (FESZ). This study demonstrates how the visual P300, as well as earlier components P1, N1, and N200, changed at the 1-year follow-up after their initial measurement.
  
  
  METHODS
  Visual ERPs were recorded with the same experimental paradigm and acquisition protocol at both time points in FESZ (n = 18) and healthy comparison subjects (n = 24). Participants silently counted infrequent target stimuli ("x") amid standard stimuli ("y") presented on the screen while the 64-channel electroencephalogram was recorded.
  
  
  RESULTS
  FESZ showed smaller visual P300, N200, P1 (trend level) amplitude and delayed P300 and N1 latency at both time points; however, only P300 showed progressive amplitude reduction over the course of the illness at 1-year follow-up. P300 latency did not change over time in either group. FESZ showed significantly reduced Spatial Span total score at both time points, and there was a significant negative correlation between P300 peak amplitude and the Brief Psychiatric Rating Scale positive symptom score at baseline.
  
  
  CONCLUSIONS
  These data show progressive P300 amplitude reduction in response to visual stimuli in the early stage of schizophrenia. These visual P300 findings support the concept of progression of schizophrenia, suggesting the usefulness of the visual P300 as a biological marker of progression.
authors.forename: Naoya
authors.initials: N
authors.lastname: Oribe
authors.forename: Yoji
authors.initials: Y
authors.lastname: Hirano
authors.affiliation: Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan;
authors.forename: Shigenobu
authors.initials: S
authors.lastname: Kanba
authors.affiliation: Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System-Brockton Division, Department of Psychiatry, Harvard Medical School, Brockton, MA;
authors.forename: Elisabetta
authors.initials: E
authors.lastname: Del Re
authors.affiliation: Massachusetts Mental Health Center Public Psychiatry Division, Beth Israel Deaconess Medical Center, Department of Psychiatry, Harvard Medical School, Boston, MA;
authors.forename: Larry
authors.initials: L
authors.lastname: Seidman
authors.affiliation: Massachusetts Mental Health Center Public Psychiatry Division, Beth Israel Deaconess Medical Center, Department of Psychiatry, Harvard Medical School, Boston, MA;
authors.forename: Raquelle
authors.initials: R
authors.lastname: Mesholam-Gately
authors.affiliation: Departments of Psychiatry and Medicine, Harvard Medical School, Brigham and Women's Hospital, Connors Center for Women's Health and Gender Biology, Boston, MA;
authors.forename: Jill M
authors.initials: JM
authors.lastname: Goldstein
authors.affiliation: Psychiatry Neuroimaging Laboratory, Departments of Psychiatry and Radiology, Brigham and Women's Hospital, Boston, MA; Research and Development, Boston Veterans Affairs Healthcare System, Boston Division, Harvard Medical School, Boston, MA.
authors.forename: Martha
authors.initials: M
authors.lastname: Shenton
authors.affiliation: Neural Dynamics Laboratory, Department of Psychiatry, Boston Veterans Affairs Healthcare System, Boston Division, Harvard Medical School, Boston, MA;
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Spencer
authors.affiliation: Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System-Brockton Division, Department of Psychiatry, Harvard Medical School, Brockton, MA;
authors.forename: Robert W
authors.initials: RW
authors.lastname: McCarley
authors.affiliation: Clinical Neuroscience Division, Laboratory of Neuroscience, VA Boston Healthcare System-Brockton Division, Department of Psychiatry, Harvard Medical School, Brockton, MA; Margaret_Niznikiewicz@hms.harvard.edu.
authors.forename: Margaret
authors.initials: M
authors.lastname: Niznikiewicz
mesh_terms: D000328:Adult; D018450:Disease Progression; D004569:Electroencephalography / Q000379:methods*; D018913:Event-Related Potentials, P300 / Q000502:physiology*; D005074:Evoked Potentials, Visual / Q000502:physiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012559:Schizophrenia / Q000503:physiopathology*
keywords: EEG; P300; first-episode schizophrenia; longitudinal; progression of schizophrenia