Advance directives preserve the person’s right to accept or reject a course of medical treatment even after the person becomes mentally or physically incapacitated to the point of being unable to communicate those wishes. Advance directives come in two basic forms: (1) a living will, in which the person outlines specific treatment guidelines that are to be followed by health care providers; (2) a health care proxy (also called a power of attorney for health care decision-making), in which the person designates a trusted individual to make medical decisions in the event that he or she becomes too incapacitated to make such decisions. Advance directive requirements vary greatly from one state to another and should therefore be drawn up in consultation with an attorney who is familiar with the laws of the particular state.

This definition is in context to Multiple Sclerosis. See more contextual defintions for Advance (Medical) Directive.