TESTING DRUGS FOR IMPAIRED BRAIN-FUNCTION IN OLD-AGE - ON THE EFFECTSOF A SINGLE-DOSE OF BIFEMELANE USING TOPOGRAPHIC MAPPING OF EEG AND EVENT-RELATED POTENTIALS (P300) AND PSYCHOMETRIC MEASUREMENTS IN HEALTHY ELDERLY SUBJECTS

Clinical studies have demonstrated that bifemelane hydrochloride [4-(o -benzylphenoxy)-N-methylbutylamine hydrochloride] can improve cognitiv e functions in patients with various types of dementia. To elucidate s pecific mechanisms which may underlie the clinical benefit, the effect s of bifemelane were investigated by means of computerized electroence phalography (EEG), event-related potentials (P300) and psychometry. Ei ghteen healthy elderly subjects, aged between 60 and 73 years, were in cluded in a double-blind, placebo-controlled crossover study. Each sub ject received a single dose of 150 mg bifemelane or placebo with an in terval of 1 week in between. EEG and psychometric investigations were carried out before and 2, 4, 6, and 8 h after drug administration, ERP investigations only before and 3 h after drug administration. Descrip tive data analysis of the EEG showed that 150 mg bifemelane accelerate d the centroid of the total frequency band, induced a significant redu ction of the absolute delta + theta power and increased the absolute b eta power most markedly 6 h after drug intake. Topographic analyses of ERP amplitudes showed that bifemelane did not effect ERP amplitudes. While N1, P2 and NZ latencies were not changed after bifemelane, P300 latency was shortened significantly. Psychometric investigations did n ot show significant or consistent effects on noopsychic and thymopsych ic functions. In conclusion, bifemelane affected EEG in the sense of i mproved vigilance. The reduction of P300 latency may be interpreted as accelerated stimulus evaluation time, therefore indicating a benefici al effect of bifemelane on cognition at this stage of information proc essing.