QUANTITATIVE EEG IN PATIENTS WITH PRESENILE AND SENILE DEMENTIA OF THE ALZHEIMER-TYPE

EEG data obtained from 27 patients with presenile Alzheimer's disease (AD) and 28 patients with senile dementia of the Alzheimer type (SDAT) were compared with data from 30 age- and sex-matched controls. Both p atient groups exhibited more pronounced delta and theta activity and l ess prominent alpha and beta activity than the controls. AD, however, was accompanied by more severe slowing than SDAT. The slowing was dist ributed in the left temporal and frontal regions in AD, and bilaterall y in the frontal regions in SDAT. As the severity of the dementia incr eased, delta activity alone increased in AD, whereas, there were signi ficantly greater increases in both delta and theta activity and decrea ses in alpha and beta activity in SDAT. These EEG differences appear t o be related to the degree of brain damage and the speed of progressio n of the disease process.