NEW YORK, Mar 15 (Reuters Health) - What is often classified as mild cognitive impairment--a condition in which a person has memory problems but few other signs of declining mental function--may actually represent a very early stage of Alzheimer's disease, researchers report.

The findings may help in the search for treatments to help ward off the memory-robbing illness, said lead author Dr. John C. Morris of Washington University School of Medicine in St. Louis, Missouri.

"I expect most people who are older to have quite good memory and thinking abilities. These people remain intact and independent. That's the good news," Morris told Reuters Health.

"If it is more than that--if it's not healthy brain aging, and people are beginning to decline--odds are that's not aging. That's disease, even though it is very mild," he explained. "We think the availability of treatments makes it worthwhile to diagnose early and initiate treatment early."

Researchers are now studying whether a class of drugs known as cholinesterase inhibitors can help people with mild cognitive impairment, Morris said.

In the study of more than 400 people aged 45 to 103, a little more than half were considered to have mild cognitive impairment while the rest had no memory problems. Some of those with mild memory problems also had signs of other difficulty with judgment, problem solving or with personal care, which are typically seen with Alzheimer's disease.

Over the 5-year observation period, only 7% of people with no memory problems went on to develop full-blown dementia. In contrast, 20% to 61% of those with mild cognitive impairment developed dementia, depending on the severity of symptoms at the beginning of the study.

Of 25 of those who died, an autopsy of brain tissue showed that 24 had a dementing disorder, including 21 cases of Alzheimer's disease, according to the report published in the March issue of the Archives of Neurology.

Morris cautioned that the study results do not mean that "anyone with any kind of memory problem is going to get Alzheimer's disease. That's pretty frightening," he added.

"I think there is a state of healthy brain aging with preserved memory and thinking abilities, and that's what we should hope for," he said. "So not every minor memory problem means you have Alzheimer's."

Researchers hope to find treatments to preserve healthy brain aging, he said.

"There is no published data, but there are lots of trials going on with currently approved cholinesterase inhibitors to see if they're effective in very mild, very early stage Alzheimer's disease," Morris noted.

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