Responders and non-responders to bifemelane hydrochloride in Alzheimer-type and multi-infarct dementia

Although metabolically active compounds sometime attenuate cognitive deficits of dementia patients, this mechanism has not been discussed or investigated. We hypothesized that these compounds improve cognitive disorders not by directly acting on this cognitive function, but by increasing the arousal level. Based on this hypothesis, we investigated the change of arousal levels and the improvement of intellectual functions in 10 patients with Alzheimer-type dementia (ATD) and 10 patients with multi-infarct dementia (MID) before and 3 months after pharmacotherapy using bifemelane hydrochloride. For each patient, a psychological test battery was carried out and the arousal level was evaluated using the frequency of rapid eye movements in the electro-oculogram (EOG) and the frequency analysis of electroencephalogram (EEG) before and after the treatment. Evaluation of the cognitive improvement was made and eight out of the 20 patients were regarded as responders to the treatment. The frequency of small rapid eye movements (SREM) in the EOG increased significantly only in responders and the rate of change in SREM appearance in responders was significantly different from that in non-responders. This finding suggests that a part of the intellectual improvement in ATD and MID results from the increased level of arousal.