Rate of cognitive decline in Alzheimer's disease is associated with EEG alpha power

Fifteen patients with Alzheimer's disease who were initially mildly or moderately impaired were followed for up to 4 years. Scores of the Mini-Mental State Examination (MMSE) were regressed on time of examination (measured at 6-month intervals) to estimate cognitive progression rates in individual patients. A quantitative electroencephalographic (EEG) examination was administered to each patient. Log-absolute EEG power in the alpha bandwidth (8-12 Hz) was found to be correlated with the computed rate of MMSE decline. This association was present for electrode sites across all regions of the scalp and remained significant when the effects of current cognitive severity were partialled out. These data suggest that a quantitative EEG measure (absolute alpha power) is related to the rate of cognitive decline in patients with Alzheimer's disease.