Period analysis of the EEG in early putative Alzheimer's disease

The EEG of patients with presumptive diagnoses of mild-to-moderate dementia of the Alzheimer type (DAT) and still residing in the community was examined using period analytic techniques. DAT patients were found to have significantly slower major and intermediate period EEG activity as compared to controls. Furthermore, one DAT patient, whose clinical EEG was read as normal, had period analytic EEG descriptors that were greater than one standard deviation below the mean of the control group. Results suggest that EEG activity, as quantified by period analysis, can be detected very early in the course of DAT.