• Long-latency event-related potentials (P300) were assessed in patients wth early probable Alzheimer's disease (AD), age-matched controls, and young adults during a task that imposed various degrees of demand on memory. Although patients with AD did not differ from age-matched controls when one item had to be remembered, their P300 potential was dramatically reduced in amplitude or absent with increasing memory load. Aged controls did not differ from young adults on this mesuer. P300 latency, however, did not differentiate patients with AD. Thus, electrophysiological abnormalities detected in the context of mnemonic demand may provide a sensitive marker of the early stages of probable AD.
Leyla deToledo-Morrell, Susan Evers, Thomas J. Hoeppner, Frank Morrell, David C. Garron, Jacob H. Fox. A 'Stress' Test for Memory DysfunctionElectrophysiologic Manifestations of Early Alzheimer's Disease. Arch Neurol. 1991;48(6):605–609. doi:10.1001/archneur.1991.00530180061018