As Alzheimer's disease progresses, patients become less able to make decisions, including decisions about their medical treatment. A group of researchers looked at Alzheimer's patients' decision-making, to help doctors and families understand when a patient may no longer be capable of making his or her own medical decisions.

What the researchers wanted to know: How does Alzheimer's disease affect patients' ability to make decisions about their treatment?

What they did: Forty-eight patients with very mild to moderate Alzheimer's and 102 caregivers were recruited from a long-term study at the University of Pennsylvania's Alzheimer's Disease Center. They were interviewed separately at home. An interviewer read each person a description of a medicine that would slow the progress of dementia, but carried some risks. Then the interviewer gave the patient or caregiver the description and asked questions like "Can you tell me how this medicine might help a person who takes it?" Psychiatrists also listened to each patient's interview to assess whether he or she was competent to make a decision about taking the medicine. Finally, a person's competence during this interview was compared to his or her score on the Mini-Mental State Examination (MMSE), a widely-used test of cognition.

What they found: Patients who score below 19 on the MMSE are very likely not competent to make medical decisions, while most patients who score 23 or higher are competent. The researchers add that those who score 20 to 22 might or might not be competent. People who knew they had memory problems or knew that it was likely they had Alzheimer's were more likely to be competent to make decisions than those who didn't have that insight.

What the study means to you: At some point, people with Alzheimer's become incapable of making decisions for themselves. This study could help doctors and relatives decide when it is time to step in to help in the decision-making. The results also underscore that patients in the very early stages of the disease can still make decisions abou their own treatment.

Caveats: The hypothetical medicine used in the interviews for this study had decent benefits and a level of risk that is generally considered acceptable in clinical practice. If the patients had been deciding about a riskier treatment with less-clear benefits, the researchers say, more of them might have been judged incompetent.

Find out more: Read information about decision-making for people with Alzheimer's, from the AGS Foundation for Health in Aging, set up by the American Geriatric Society.

Read the article: Karlawish, J.H.T., et al. "The Ability of Persons With Alzheimer Disease (AD) to Make a Decision About Taking an AD Treatment." Neurology. May 10, 2005, Vol. 64, pp. 1514-1519.

Abstract online: http://www.neurology.org