Now she was choking on her puréed food; eating was becoming impossible. So the administrators of her nursing home in Hickory, North Carolina, asked Mull's daughter what to do: Did she want a feeding tube inserted? At that point, Mull muttered only a few random words and could no longer recognize her daughter. The feeding tube would almost certainly prolong her life, but was it worth it? .

The question of how aggressive to be in treating late-stage Alzheimer's patients is one of the most wrenching and contentious issues in medicine. For every patient who, like Mull, reaches the final stage of the disease, there typically are about five or six family members faced with decisions about whether to authorize medical treatments for patients whose bodies live on though their minds are gone.

Research has found that Alzheimer's patients at the end of their lives often receive everything that medicine has to offer - feeding tubes, intravenous fluids and antibiotics and hospitalizations - more treatment than cancer patients at the end of their lives. But Alzheimer's patients rarely receive the palliative care intended to relieve suffering but not to prolong life that is normal in cancer cases; they make up only 7 percent of people who receive hospice care.

The comparison with cancer patients is imperfect, because cancer patients often die more quickly, and because they, unlike Alzheimer's patients, can speak for themselves about their care. But some experts and family members argue that intensive treatment in cases of late-stage Alzheimer's patients is inappropriate, even cruel, and that its costs are excessively high. Some end-stage Alzheimer's patients get dialysis when their kidneys fail. Infections are treated with intravenous antibiotics. Patients are rushed to hospitals and intensive care units when they fall ill. .

Putting in a feeding tube can cost about $2,000, said Douglas Nelson, a geriatrician in Hickory, whose practice mostly consists of nursing home patients. Inserting a tube requires a consultation with a speech therapist to verify that food is accidentally entering the lungs and an X-ray by a radiologist that requires swallowing barium. The procedure itself is done in a hospital, with an anesthesiologist and a gastroenterologist or a general surgeon.

A feeding tube can prolong life in a nursing home, which quickly dwarfs the cost of putting in the tube. In North Carolina, Nelson said, it costs $150 a day on average, not counting medication, to care for a patient in a nursing home.

"The economics are horrific," said Steven DeKosky, director of the Alzheimer's Disease Research Center at the University of Pittsburgh. .

Diane Meier, a professor of geriatrics and ethics at Mount Sinai School of Medicine in Manhattan, agreed. "We are spending a huge amount of money keeping people with irreversible brain failure alive," she said. "If the technology exists, we feel we must use it. Our colleagues in Europe consider what we do bizarre to the point of disbelief." .

Others contend that to withhold treatment is to hasten death, in effect, playing God.

"There are people in my field who have legitimate concerns that we might be too eager to pull the plug," said Christine Cassel, an expert in geriatrics, ethics and end-of-life care, and president of the American Board of Internal Medicine. "Just because someone has Alzheimer's disease doesn't mean their life has no value."

With tube feeding and medical treatment for each medical crisis, end-stage Alzheimer's patients can live on, sometimes for years. Many no longer recognize family members, speak no more than a word or two, cannot walk or eat, and are prone to repeated urinary tract infections and bouts of pneumonia.

Family members and doctors must decide what steps to take. But many find themselves at a loss. "People desperately need some guidance," DeKosky said. "Everyone, including the docs, is saying: 'Tell us what's O.K. Tell us what's appropriate.'"

Often, doctors simply treat the conditions as they arise, putting off conversations about where, and whether, to draw a line. "Some physicians and health-care providers find it difficult to talk about these things," Mitchell said. "And it takes a lot of time and effort, which for the most part is not well reimbursed."

But even when the issue of ending aggressive care arises, family members often disagree about what is going on in the mind of a patient. "A family member sees what they see as a light of recognition, even if other people standing there can't be sure they saw it," DeKosky said. "On the other hand, a flicker of recognition isn't the answer. It isn't saying, 'Yes, he's still in there.'"

In Mull's case, her daughter, Patricia Hollar, was torn. Her heart told her that maybe enough was enough, she said. But she was worried that her two brothers and sister might think she was condemning their mother to death. She told the nursing home to put in the tube.

Randy Bryant of Taylorsville, North Carolina, chose a feeding tube for his mother, Hattie Kuykendall, 89, who has advanced Alzheimer's and lives in a nursing home nearby. He had little hesitation, he said. "With a lot of people, it's an easy decision to just let people go ahead and pass away," he said. "When it's your mother, you can't do that. Would you let your mom die?" . Nelson reached a crisis of conscience. "The more I started looking at these poor people with feeding tubes, the more guilty I started becoming," he said. "Am I sinning?" he asked himself, wondering whether it was right to stand by while patients suffered with pain and discomfort from the tubes and other treatments.

In November, he introduced a position paper to his state medical society, which it passed unanimously, saying that tube feeding was not good medicine for end-stage dementia patients. He also counsels families. When Alzheimer's patients can no longer eat, Nelson said, "My advice is to let the patient die peacefully."