"These results are yet another reason why people should consult a doctor if they notice any warning signs of Alzheimer's in themselves or a loved one," said study author Jason Karlawish, MD, of the University of Pennsylvania in Philadelphia. "An early diagnosis can help assure that patients can participate in decisions about their care."

For the study, researchers interviewed 48 people with very mild to moderate Alzheimer's disease and 102 caregivers of people with mild to severe Alzheimer's. The patients' decision-making abilities were measured by giving them information about the benefits and risks of a hypothetical treatment for Alzheimer's and asking them to make a choice whether they would take the treatment. Then experts assessed whether they were competent to make the decision.

Of the 48 patients, 19 were found to be competent in making the decision.

The study found that scores on the Mini-Mental State Examination (MMSE), a widely used rating scale for cognitive abilities, can help predict patients' decision-making abilities. Those with scores of 11 to 19 on the scale, which indicates moderate dementia, were not likely to be competent decision-makers. Those with scores of 24 and higher, which indicates very mild dementia, were likely to be competent decision-makers.

Those with scores of 20 to 23, with mild to early moderate Alzheimer's, are in a gray zone, Karlawish said. "If there are questions about the competence of a person in this range, it would make sense to do a detailed assessment of that person's decision-making abilities," he said. "Of course, the MMSE score is just one piece of information. People below this range are less likely to retain adequate decision-making abilities, but some may."

Another finding of the study was that people who were aware of their diagnosis, symptoms, and prognosis were more likely to be able to make competent decisions. This insight into their condition was not related to the severity of the disease.

"This finding shows us that the mere presence of a dementia diagnosis does not preclude the patient from participating in decisions about his or her own care," said neurologist Michael McQuillen, MD, MA, of the University of Rochester in Rochester, N.Y., who wrote an editorial accompanying the study.

Karlawish said, "The study also suggests that the loss of awareness of a patient's condition may be a sign that the patient is no longer able to competently make decisions about their treatment."

The study also found that 40 percent of the patients could understand how the risks of the hypothetical treatment would apply to them, while only 15 percent could appreciate how the treatment's benefits would apply to them.

Karlawish said the results may be helpful because, while current Alzheimer's treatments have few substantial risks, potential treatments that are under development may have substantial risks. "Doctors and family members could benefit from having a method to know if the person is capable of deciding whether to undergo a risky treatment," he said.
The study was supported by grants from the National Institute on Aging, a Paul Beeson Physician Faculty Scholars in Aging Research award from the John A. Hartford Foundation, and a Greenwall Faculty Scholar in Bioethics award from the Greenwall Foundation.

The American Academy of Neurology, an association of more than 18,000 neurologists and neuroscience professionals, is dedicated to improving patient care through education and research. A neurologist is a doctor with specialized training in diagnosing, treating and managing disorders of the brain and nervous system such as Parkinson's disease, dementia, ALS, narcolepsy, and ataxia.