Changes in sensitivity to stimulus deviance in Alzheimer's disease: An ERP perspective

THE mismatch negativity (MMN) of the event-related brain potential (ERP) reflects the storage of information in sensory memory. MMNs were recorded from eight patients with Alzheimer's disease (AD) and eight controls to small (Delta 50 Hz), large (Delta 300 Hz), and a variety of highly deviant, environmental sounds. Both old controls and patients showed robust MMNs to all three classes of deviant events, and robust P3 compounds (indicative of active attention) to the environmental sounds. The data suggest that patients with mild AD have an intact sensory memory mechanism that responds similarly to that of controls to systematic increases in deviance. Ho Never, for both older controls and patients, only highly deviant acoustic events are likely to involuntary capture attention. (C) 1999 Lippincott Williams & Wilkins.