[Viewpoints on the therapeutic trials in senile cerebral insufficiency]

The experience acquired and a better understanding of the pathogenesis of cerebral impairment in elderly subjects have enabled the authors to propose certain rules for therapeutic trials in such patients. The patient population should be homogeneous with regard to the severity of cerebral impairment. A clear-cut distinction should be made between at least two categories of patients: those at home and those in institutions. Impairments due to different causes (arteriopathy, parkinsonism, traumas, chronic intoxication, idiopathic) require different trials. Criteria of assessment should intervene at recruitment to homogenize the degrees of severity. They should be consistent with the purpose of the trial (pragmatic or explicative) and with its duration and the number of subjects involved. In pragmatic trials assessment should be based on changes in social and affective relationships or even changes in the likelihood of admission to an institution. Assessment scales using psychometric, clinical and socio-affective criteria may be used provided the importance of each criterion is weighed beforehand and the results concern overall changes rather than changes of any particular item. Such trials are necessarily protracted and involve a large number of patients. Psychometric and neurophysiological tests seem to be best suited to explicative trials, as they are reproducible and easily performed. While they may demonstrate the effects of the drug on memory, mood, alertness, etc., or merely show an impact on the central nervous system, this does not necessarily mean that they are of interest in senile cerebral impairment. Explicative trials, which are shorter and require less patients, help to select the drugs suitable for long-term trials. Finally concerning the three topics constantly debated when organizing such trials, viz, maximum age of the subjects, use of a cross-over method and association of psychotropic drugs, the authors' opinion is: (a) there is no reason for an upper age limit; (b) cross-over studies should be avoided, and (c) psychotropic drugs must be banned in short-term trials but are unavoidable in long-term trials.