EEG spectral analysis in Alzheimer's disease and different degenerative dementias

The EEG was recorded in 25 patients with Alzheimer's disease (AD), 25 patients with non-Alzheimer degenerative dementias (NAD), matched for age and severity of dementia and 50 age- and sex-matched normal subjects. The recordings were made with the subjects at rest with eyes closed (REC) and opened (REO). The data was subjected to spectral analysis and the power was computed in five contiguous 5.5 Hz bandwidths in the range 1-28.5 Hz. The present study confirms the consistent prevalence of a spectrum characterised by the lack of a dominant activity in the 6.5-12 Hz band with high power in 1-6.5 Hz band in AD. Moreover quantitative spectral parameters discriminate not only AD from the other groups, but also NAD from age matched normal subjects.