EEG COHERENCE IN ALZHEIMER-DISEASE

A novel approach is introduced to examine EEG coherence in different f requency bands of 17 locations from the 10-20 system. Fifty patients w ith clinically diagnosed Alzheimer's disease were compared with 42 age -approximated non-demented controls. We determined the average coheren ce between individual electrodes and all neigbouring electrodes. Coher ence was decreased in the sample of demented patients and this effect was most pronounced in the frontal and central derivations of the thet a, alpha and beta frequency bands. The results can be interpreted as t he effects of neuronal loss and neocortical disconnection.