Bill Crist was angry and upset when his doctor diagnosed him with dementia (search). But the 64-year-old retired pharmacist felt a little better after going to the Center for BrainHealth (search) for an evaluation, which showed his language skills and memory were still quite strong.

Crist suffers from a neurodegenerative (search) disorder that is associated with Alzheimer's (search) and Parkinson's disease (search). He said the follow-up test helped show him which brain functions "look normal."

Such exams are becoming increasingly popular as aging Americans try to differentiate between normal aging problems and the effects of neurological conditions.

The three-hour screenings cost $350 and are not covered by insurance. Many people get tested even when they aren't showing signs of brain problems.

"It's perfectly appropriate if a person has some anxiety — why not go in and have experts assess you?" said Dr. George M. Martin, professor emeritus of pathology at the University of Washington and the scientific director of the American Federation for Aging Research.

The brain center was founded in 1999 as part of the University of Texas at Dallas' School of Behavior and Brain Science.

As word has spread, the number of screenings has gone up sharply, said Jennifer Zientz, head of diagnostic services for the Center for BrainHealth. Last year the center did 160 checkups, compared with about 50 the prior year.

Molly Keebler, the center's head of community programs, even had her 84-year-old mother tested after she noticed her mother stopped doing some things she usually enjoyed, like keeping a journal.

Her mother, Naomi Williams, got a clean bill of health, and some tips on how to stay sharp. She now keeps a notebook in her purse to jot down reminders and has kept up activities such as reading and going to movies.

"The screening made me feel very uplifted," Williams said.

Zientz said the screenings look at how people process complex information. For people like Crist, who already know they have dementia, the screening helps them focus on their mental strengths.

The screening includes several verbal tests, such as interpreting and explaining proverbs. For example, a healthy person could easily interpret "Don't judge a book by its cover." But someone with cognitive problems might say it means you have to read a book to know what's in it.

When problems are found in the screening, the center refers the patient to a doctor.

Slight downward shifts in mental capacity can be a sign of strokes, kidney malfunction, stress or depression, said Dr. Sandra Chapman, the center's director.

"The earlier you detect a glitch in the brain, the more that can be done," she said.

The best candidates for screenings are people who have noticed changes in their memory, said Dr. Randolph Schiffer, chair of the department of neuropsychiatry and behavioral science at Texas Tech University.

Dr. Bill Woodfin, a Dallas neurologist, said the center not only allows people to talk frankly about the challenges of memory loss, but also helps them understand how they can improve their memory.

"I would anticipate more people in my position — physicians, psychologists who see people with these problems — to refer patients more frequently" for such tests, said Woodfin, who referred about six people to the center last year.

On a much simpler level, the exam gives patients and their families some positive news during a difficult time.

Bill Crist's wife, Peggy, said the tests give patients something positive, rather than negative, to focus on.

"I know it sounds hokey, but it's something you need when you get a diagnosis like that," she said.