Findings of electroencephalographic brain mapping in mild to moderate dementia of the Alzheimer type during resting, motor, and music-perception conditions.

Sixteen-channel electroencephalographic (EEG) brain mapping studies were carried out under resting conditions in 41 patients with mild to moderate dementia of the Alzheimer type, diagnosed according to DSM-III-R criteria. The patients showed diffuse patterns of EEG slowing, as known from the literature. They showed increases of theta power in large bilateral brain areas and bitemporal increases of delta power as compared with both age-matched and younger control subjects. In addition, the patients had increased beta activity in comparison with the younger control group, but not with the age-matched control subjects. Functional brain mapping revealed decreases of EEG power during manual-motor and music-perception tasks in delta frequencies for patients, which was not seen in either of the two control groups. All frequency bands revealed major gender-related differences in EEG activity, which should receive more attention in future research.