EEG changes during long-term treatment with donepezil in Alzheimer's disease patients

In this pilot study, we examined the long-term treatment effect of donepezi l on the quantitative EEG (qEEG) in 12 Alzheimer's disease patients. The qE EGs of the mean absolute and relative amplitudes of betal, alpha, theta and delta activities were obtained at baseline and during donepezil treatment. Comparisons of awake qEEG prior to and during treatment were performed usi ng a 2-way analysis of variance (ANOVA) with repeated measures. In patients with mild dementia (n = 5), the qEEG analysis showed a signific ant reduction of the mean absolute theta activity (p = 0.05) by donepezil, particularly in frontal and temporo-parietal areas. In patients with modera te/severe dementia (n = 7), a significant decrease in the mean absolute bet a I activity (p = 0.02), particularly in the frontal and occipital areas ma y be attributed to disease progression which was not counteracted by the lo ng-term treatment. The differences in qEEG in patients with different stages of dementia under donepezil treatment may be related to different compensatory capacities du e to structural and functional brain disturbances.