[Ethical dilemma in research: informed consent in clinical studies on persons with dementia].

With the world's population aging, there is an increase in the number of demented elderly. It is vital to study this phenomenon in epidemiological and clinical studies, particularly the effects on the increasing numbers of demented elderly. Researchers need to understand the factors predicting the general decline in the demented elderly. However, before any research is undertaken, it is necessary to obtain approval from the Local Internal Review Board. This committee is responsible to maintain accepted national and international ethical standards. The basis for recruitment to a study is the signature on the informed consent form, where the patient is required to understand the study, internalize the study's aim, to consider all options and finally, to express an opinion. Potential elderly participants need to have their judgment evaluated before signing the form. In cases where the subject is incapable, some countries, including Israel, require that there be a legal guardianship. This is a long and complicated process that causes researchers not to recruit demented patients into a study which may actually be beneficial to all. Some countries allow a proxy to sign informed consent forms to permit the demented subject to participate in the study. Often the threshold may depend on the invasiveness of the intervention. The problem of proxies to sign informed consent form troubles researchers worldwide. This article addresses the history and development of ethics in research, and raises the issue to promote an official policy for proxy consent signing.