The purpose of this study is to assess decision-making capacity in persons with Alzheimer's disease. First, our goal is to validate four French capacity assessment tools for persons with Alzheimer's Disease : a French version of the Competency Assessment Tool for Consent to Treatment and of the Competency Assessment Tool for Voting, two questionnaires assessing the capacity to appoint a proxy either to consent to treatment or to vote. Second, once validated, we plan these questionnaires to study decision-making abilities and their determinants in persons with Alzheimer's disease and control subjects.

Study of Alzheimer's disease patients show a wide variability in decision-making abilities, especially for the consent to treatment and the ability to vote. No tools are available to assess the capacity to design a proxy. The purpose of this research is to assess simultaneously four decision-making abilities in persons with Alzheimer's disease: the capacity to consent to treatment, the capacity to vote and the capacity to design a proxy either to consent to treatment or to vote.

This study will recruit 320 patients with Alzheimer's disease and 80 non-demented control subjects. Four decision-making questionnaires will be administered to participants to explore participant capacity to understand, reason, appreciate and make a choice about the capacity to consent to treatment, to vote and to design a proxy either to consent to treatment or to vote. Once validated in the first part of this research, the questionnaires will be used to study decision-making abilities and their determinants in patients with Alzheimer's disease and control subjects.

Inclusion Criteria:

• for patients with Alzheimer's disease: age >=18 years, to be native speakers of French and French nationality, Diagnosed with a Alzheimer's disease and followed in a French "Centre Memory of Resources and Research"(CMRR)
• for control subjects: age >=18 years, to be native speakers of French and French nationality, have no complaints of memory problems, primary caregiver of patient with AD of the same age as the patient nearly 10 years

Exclusion Criteria:

• for all participants: confusion, severe psychiatric disorders, stroke, blindness, uncorrected hearing loss, refusal to participate in the study
• for patients with Alzheimer's disease: other dementia than AD
• for control subjects: diagnosed dementia

persons with Alzheimer's disease