N400 abnormalities in late life schizophrenia and related psychoses

John M Olichney, Vicente J. Iragui, Marta Kutas, Ralph Nowacki, Dilip V. Jeste

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Abstract

The N400, an event-related brain potential (ERP) sensitive to semantic congruity, has been reported to have increased latency and/or reduced amplitude in young adults with schizophrenia. Little is known, however, regarding the N400 in older schizophrenia patients, especially those with late onset. We studied 18 middle-aged and elderly patients with schizophrenia and related psychoses (nine with early-onset psychosis (EOP) and nine with late-onset psychosis (LOP)), and nine normal comparison (NC) subjects. Subjects read words which were semantically incongruent (50%) or congruent (50%) with a preceding spoken phrase which defined either an antonymic or categorical relationship. The LOP group had a significantly later peak latency of the N400 congruity effect compared to the NC group. Seven of 18 psychosis patients, but none (0/9) of the normal subjects, had an abnormal latency or amplitude (p = 0.04), measured at T6 (right temporal). Smaller amplitudes were associated with more severe negative symptoms (r(p) = 0.58; p = 0.01). N400 abnormalities in older schizophrenia patients likely reflect abnormal processing of semantic information.

Original languageEnglish (US)
Pages (from-to)13-23
Number of pages11
JournalBiological Psychiatry
Volume42
Issue number1
DOIs
StatePublished - Jul 1 1997

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Keywords

  • Aging
  • Event-related potential
  • Language
  • Psychophysiology
  • Semantic network

ASJC Scopus subject areas

  • Biological Psychiatry

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