My father, John Foskett, turns 89 next month, though you'd never know it from his baseline volley. He plays tennis twice a week, competes in senior tournaments and is trimmer today than when he graduated from college in 1947 (six years late because of World War II).

Recently, however, my father confided a nagging concern: his memory. He forgets names, or tasks he intended for the day. He organizes his desk, only to do it all over again because he can't quite recall where things are.

(ENLARGE)

Alzheimer's test can help seniors with early symptoms prepare for the disease.

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Could it be, my father wondered, a sign of Alzheimer's?

According to doctors, millions of older Americans are posing the same question. Many, like my father, have dodged serious disease and illness only to find that age is beginning to dull their mind.

Health officials predict that 16 million Americans will develop Alzheimer's by 2050, as American baby boomers live longer. Statistically, the odds of developing Alzheimer's are 50-50 for those older than 85.

Risk remains low throughout middle age but begins to increase steadily after age 65.

So, what's a person to do?

Although Alzheimer's has been around since 1906, the medical advice about how and when to test for the disease is still evolving. A generation ago, many doctors considered testing for Alzheimer's a waste of time because no one knew how to treat it.

But new drugs, combined with the difficult care decisions that accompany an Alzheimer's diagnosis, have prompted more doctors to urge older patients to have themselves evaluated for cognitive problems as soon as they appear.

"We still have this notion that you get old, you get senile," says Dr. Paul Solomon, clinical director of the Memory Clinic in Burlington, Vt. "But senility and cognitive deficits are not typical of the aging process. They signal a disease process."

Doctors argue that older people need to think of the function of their mind as they would the condition of their heart or the stability of their blood pressure.

For the moment, however, the onus to seek testing is on the patient. Doctors will not test for Alzheimer's or other cognitive disorders unless asked, which has resulted in huge numbers of undiagnosed cases.

"The number of patients diagnosed early is abysmally small," says Dr. Allan Levey, chairman of neurology at Emory University and director of the Alzheimer's Disease Research Center. "We need to be identifying people even earlier on."

Basic screens to test for cognitive function can take as little as five minutes. Most involve a person's ability to immediately recall names or words given to them a few minutes earlier, since one indication of Alzheimer's is a decline in short-term memory.

Another test involves having the patient draw the face of a clock and indicate a specific time of day. Alzheimer's also interferes with the brain's problem-solving ability, so a patient with Alzheimer's often has trouble placing the clock hands in the right sequence or drawing the numbers in the proper order.

Such screens do not by themselves lead to a diagnosis of Alzheimer's. But low scores could suggest the need for more detailed testing. (A more accurate assessment of brain function, administered by a neurologist, takes 90 minutes or more.)

Even if the simple screens show no problems, doctors say they can be helpful. An annual cognition screen, just like a regular blood pressure reading, can show what's happening to someone's mental function over time.

Moderate declines in cognitive ability also can be treated with several drugs. They do not cure Alzheimer's, but they can slow worsening symptoms and improve memory function. All are covered by Medicare.

Other, more promising drugs are in the research pipeline, including several vaccines that may actually reverse the deadly progress of Alzheimer's through the brain. Those diagnosed with Alzheimer's are eligible to participate in clinical trials testing the new drugs. The government lists clinical trials by region at www.clinicaltrials.gov.

Health care professionals also believe older people — and their families — are better off if they confirm an Alzheimer's diagnosis sooner rather than later. Alzheimer's is an irreversible, degenerative disorder that slowly causes brain cells to die.

Patients can do well cared for at home in the initial phases, but they require increasing levels of care and supervision as the disease progresses. Patients also lose the ability to make financial decisions, so an early diagnosis means it's time to get their affairs in order.

James Abercrombie, 86, learned he had Alzheimer's in 1998. For many good years, he stayed home in Newnan with his wife. The couple moved to an assisted-living home in Decatur two years ago because Ruth Abercrombie could no longer manage alone. James Abercrombie said he misses his garden, although he's started one at his new residence. He's also two miles from his son, Jon, who can visit his parents more often now.

"We were afraid we would lose him in the first few years or so," said Jon Abercrombie. "But he's done real well."

TRUTH AND MYTHS:

Only older people can get Alzheimer's.

Actually, Alzheimer's can strike people in their 30s, 40s and 50s. Of the estimated 5 million Americans living with the disease, some 500,000 under age 65 have Alzheimer's or a related dementia.

Memory loss is a natural part of aging.

Severe memory loss is a symptom of serious illness. It's still not clear whether memory naturally declines as a person grows older.

Alzheimer's disease is not fatal.

Alzheimer's disease will kill you. It destroys brain cells and eventually results in a loss of body functions.

Drinking out of aluminum cans or cooking in aluminum pots and pans can lead to Alzheimer's disease.

During the 1960s and 1970s, aluminum emerged as a possible suspect in Alzheimer's disease, leading to concerns about exposure to pots and pans, beverage cans, antacids and antiperspirants. But experts haven't confirmed any link between the disease and aluminum, and few believe that everyday sources of aluminum pose any threat.

The artificial sweetener aspartame, marketed under the names Nutrasweet and Equal, causes memory loss.

As of May 2006, the Food and Drug Administration had not been presented with any scientific evidence that would lead it to change its conclusions on the safety of aspartame for most people. The agency says its conclusions are based on more than 100 laboratory and clinical studies.

Flu shots increase risk of Alzheimer's disease.

A theory linking flu shots to a greatly increased risk of Alzheimer's disease has been proposed by a U.S. doctor whose license was suspended by the South Carolina Board of Medical Examiners. Several mainstream studies link flu shots and other vaccinations to a reduced risk of Alzheimer's disease and overall better health.

Silver dental fillings increase risk of Alzheimer's disease.

According to the best available scientific evidence, there is no relationship between silver dental fillings and Alzheimer's.

Source: Alzheimer's Association, www.alz.org

WHAT IS DEMENTIA?

Dementia is a general term for loss of memory and other mental abilities severe enough to interfere with daily life. It's caused by physical changes in the brain. The term senile pertains to the mental decline once associated with old age but now known to be due to dementia.

Alzheimer's disease is the most common type of dementia, accounting for 50 percent to 70 percent of cases. A small percentage of Alzheimer's disease is inherited, and is usually characterized by early onset of symptoms, often before the age of 50. The vast majority of Alzheimer's is characterized as sporadic, and generally occurs after the age of 65.

Other types of dementia include:

• Vascular dementia: Arteries feeding the brain become narrowed or blocked. The onset of symptoms usually is abrupt, frequently occurring after a stroke. It develops when impaired blood flow to parts of the brain deprives cells of food and oxygen.

• Lewy body dementia: Characterized by abnormal deposits of a protein called alpha-synuclein that form inside the brain's nerve cells.

• Frontotemporal dementia: A rare disorder that affects the front (frontal lobes) and the sides (temporal lobes) of the brain. Because it affects the areas of the brain that are responsible for judgment and social behavior, frontotemporal dementia can result in socially inappropriate behavior. Symptoms of this form of dementia, which runs in families, usually appear between the ages of 40 and 65.

Sources: Alzheimer's Association, Mayo Clinic, medicinenet.com