Ethical and practical aspects of research involving demented subjects

This article discusses the ethical problems in research involving patients with impaired cognition. It reviews the bases of the legislation in the United States, where it has existed for several decades, and in France where the laws concerning biomedical research are more recent. The few studies that have attempted to objectively define the concept of competency and its possible correlates are presented. One study has shown that the strongest predictors of incompetence are, in descending order, word fluency measures, expressive language, and executive functions, thus suggesting a relationship between competency and frontal lobe structures. We conclude with some recommendations based on current practices and on pending proposals. These include advanced directives, consent by proxy, therapeutic guardianship, and collective consent by IRB's.