Evaluations of dementia by EEG frequency analysis and psychological examination.

In order to evaluate the stage of dementia, we focused attention on EEG rhythms and Hasegawa-dementia-rating scale (HDS-R). Frontal EEGs were recorded from dementia patients and normal controls during music and photo-image stimulations, and frequency analysis was performed. In the controls, profiles of rhythm pattern during music stimulation seemed to be markedly different from those during photo-image stimulation. In contrast, in dementia patients, it was difficult to find those differences. Interestingly, as HDS-R decreases, the variability of rhythm patterns also decreases. These results suggest that a decrease in cognitive function might be related to a decrease in the ability to generate various cortical rhythm patterns.