Timing of disease progression by quantitative EEG in Alzheimer's patients

This prospective study was planned to assess whether quantitative EEG (qEEG ) can give an estimate of the tinting of achievement of three endpoints (lo ss of activities of daily living, incontinence, and death) in 72 consecutiv e patients (53 females, 19 males; mean age, 70.8) affected with probable Al zheimer's disease, as defined according to the NTNCDS-ADRDA criteria. Power -weighted, log-transformed relative values of the four conventional EEG ban ds were considered in a central-posterior temporal region for each hemisphe re. The hypothesis was tested by the lifereg procedure of the Statistical A nalysis System package (first significance level accepted, P less than or e qual to 0.01). Because patients were in different stages of the disease, th e statistical analysis was performed in the entire group as well as in the subgroup of 41 patients (mean age, 69.6) with mild dementia (scoring 3 or 4 on the global deterioration scale). In the whole group, the loss of activi ties of daily living was predicted by delta power in either side (P = 0.01) , incontinence was predicted by alpha power in the right side (P < 0.01), w hereas the statistical significance was not reached for death (P < 0.05). I n the subgroup of mild demented patients, the loss of activities of daily l iving was predicted by delta power in the left side (P = 0.01), incontinenc e by both delta (P < 0.01) and alpha (P < 0.001) power in the right side, a nd death was not significantly predicted (P = 0.08). Quantitative EEG is a low-cost, discomfort-free technique which may be used to obtain information on the timing of disease evolution. The results showed in mild Alzheimer's disease appear especially interesting to attempt a prediction of the futur e time course of the disease from its beginning.