[Methodology of a controlled trial of dihydroergotoxine in acquired intellectual impairment in the adult].

The aim of the trial was to compare the clinical efficacy of dihydroergotoxin with a placebo, and to define its indications in the treatment of acquired dementia of abiotrophic origin (degeneration by primary cerebral atrophy) or arteriopathic (deterioration as the result of multiple cerebral infarcts) origin. It was a single centre, double-blind, randomized, controlled, experimental clinical trial. The trial involved 3 groups, each corresponding to a stage of increasing severity. Each group was randomized separately. The separation between the abiotrophic dementia group and the arteriopathic dementia group was made after the trial, on the basis of clinical criteria (Hachinski ischemic score), and a scan when applicable. The number of subjects necessary was fixed at 100 (33 per group). The duration of the trial was 6 months per patient.