EEG and the passive P300 in dementia of the Alzheimer type.

Quantitatively analyzed resting electroencephalographic (EEG) activity and P300 event-related potentials elicited with a passive tone sequence paradigm were examined in 30 patients with dementia of the Alzheimer type (DAT) and 15 age matched controls. Background electrical rhythms of DAT patients evidenced slowing as shown by increased absolute and relative amplitudes in slow frequency bands and decreased amplitudes in fast frequency bands (relative to controls). Electrical slowing was more evident in patients with higher clinical ratings of global intellectual deterioration. Passive P300 amplitude and latency did not differentiate patients and controls and were not related to severity of dementia.