Impaired decision-making ability in subjects with Alzheimer's disease and willingness to participate in research.

OBJECTIVE: Ethical concerns persist over research participation of decisionally impaired persons, such as those suffering from Alzheimer's disease. Such persons may be poor judges of the burdens and risks of specific research protocols. Since even decisionally incapacitated persons cannot be enrolled in studies against their objection, their preferences convey important ethical information. The authors examined the effects of cognitive and decisional impairment on willingness to participate in research among persons with Alzheimer's disease.
METHOD: Cognitive status, decision-making ability, and willingness to participate in four hypothetical research protocols of varying risk/benefit profiles were measured in 34 subjects with mild to mild/moderate Alzheimer's disease and 14 healthy elderly comparison subjects. Univariate and multivariate methods were used to analyze the effects of impairment in cognitive and decision-making abilities on willingness to participate in research.
RESULTS: There were no differences in willingness to participate found between the Alzheimer's and the healthy comparison subjects for three of the four hypothetical protocols. In both groups, willingness declined as risk increased. Within the Alzheimer's disease group, the presence of greater decisional impairment tended to predict less willingness to participate in research, even after adjusting for cognitive impairment, gender, and education.
CONCLUSIONS: Persons with decisional impairment due to Alzheimer's disease are as a group able to distinguish between research protocols of varying risk/benefit profiles. Because declining decision-making abilities may predict declining willingness to participate in research, informed consent procedures for Alzheimer's disease research should be sensitive to this possibility.