N400 abnormalities in late life schizophrenia and related psychoses

Biol Psychiatry. 1997 Jul 1;42(1):13-23. doi: 10.1016/S0006-3223(96)00242-9.

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 (rp = 0.58; p = 0.01). N400 abnormalities in older schizophrenia patients likely reflect abnormal processing of semantic information.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Arousal / physiology*
  • Attention / physiology*
  • Brain Mapping
  • Cerebral Cortex / physiopathology
  • Chronic Disease
  • Dominance, Cerebral / physiology
  • Electroencephalography*
  • Evoked Potentials / physiology
  • Female
  • Humans
  • Male
  • Middle Aged
  • Psychiatric Status Rating Scales
  • Psychotic Disorders / diagnosis
  • Psychotic Disorders / physiopathology*
  • Psychotic Disorders / psychology
  • Reaction Time / physiology
  • Reading*
  • Reference Values
  • Schizophrenia / diagnosis
  • Schizophrenia / physiopathology*
  • Schizophrenic Psychology*
  • Semantics
  • Speech Perception / physiology*