Clinical research and the noninstitutional elderly: a model for subject recruitment.

Two approaches (normative and symptomatic) are presented for recruiting volunteers for a study of the effects of a vasodilator on the psychophysiologic functioning of elderly patients with mild to moderate cerebroarteriosclerosis. The subjects had to be at least 60 years old, in good physical and emotional health, of at least average intelligence, manifesting cognitive impairment by at least one of several test measures, maintaining themselves in the community, and active in a senior citizens program. Results of both approaches were compared for rates of volunteer response, study eligibility, and admission to the study. The normative approach emphasized data on the normal cognitive changes associated with the aging process. The symptomatic approach focused on the early diagnosis and treatment of an existing cognitive impairment. A combined total of 1,030 potential volunteers, nearly equally divided according to the two techmiques, were addressed in group meetings. With the normative approach, 33 percent volunteered; of this group, 27 percent were found eligible for the study, and of these, 10 percent entered the study. With the symptomatic approach, 36 percent volunteered; of this group, 54 percent were found eligible for the study, and of these, 51 percent entered the study. Thus the symptomatic approach was five times more effective than the normative approach.