Assessment of Medical Decision-making Capacity in Patients With Dementia

Medical decision-making capacity, the patient's ability to exercise autonomy reasonably, is an essential component of both informed consent and informed refusal. The assessment of medical decision-making capacity is thus fundamental to the ethical practice of medicine. Medical decision-making capacity is not all or nothing but rather exists on a continuum and should be assessed on a decision-by-decision basis. Alzheimer disease and other neurocognitive disorders can affect a patient's medical decision-making capacity and may pose special challenges to capacity assessment. To illustrate some of these challenges, this article presents a case of a patient with Alzheimer disease who refused a recommended operation and discusses the components of capacity, a useful mnemonic and tools, the variability of state laws, and the roles neurologists and psychiatrists play in the assessment of capacity.