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

THE mismatch negativity (MMN) of the event-related brain potential (ERP) re flects the storage of information in sensory memory. MMNs were recorded fro m 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, envir onmental sounds. Both old controls and patients showed robust MMNs to all t hree classes of deviant events, and robust P3 compounds (indicative of acti ve attention) to the environmental sounds. The data suggest that patients w ith mild AD have an intact sensory memory mechanism that responds similarly to that of controls to systematic increases in deviance. Ho Never, for bot h older controls and patients, only highly deviant acoustic events are like ly to involuntary capture attention. (C) 1999 Lippincott Williams & Wilkins .