The definition of autonomy is the ability of an individual to make a rational, uninfluenced decision. Therefore, it can be said that autonomy is a general indicator of a healthy mind and body. The progression of many terminal diseases are characterized by loss of autonomy, in various manners and extents. For example, dementia, a chronic and progressive disease that attacks the brain can induce memory loss and cause a decrease in rational thinking, almost always results in the loss of autonomy.