Is it Mild Cognitive Impairment or Alzheimer's?

More than 90 percent of older adults diagnosed with mild Alzheimer's would be re-diagnosed as having the less serious condition of mild cognitive impairment, according to a study that looks at newly revised diagnosis criteria.

The new criteria for diagnosing mild Alzheimer's were issued last year by experts with the National Institute on Aging and the Alzheimer's Association.

John C. Morris, M.D., director of the Knight Alzheimer's Disease Research Center at Washington University in St. Louis, decided to look at how the new criteria would affect those diagnosed under the older criteria.

He studied the neurological evaluations of 17,535 adults -- average age about 75 -- who were diagnosed as having normal cognition, mild cognitive impairment or Alzheimer's disease.

He found that that 99.8% of the people currently diagnosed with very mild Alzheimer's disease and 92.7% of people currently diagnosed with mild Alzheimer's disease could be reclassified as having mild cognitive impairment under the new guidelines.

So what difference does a new diagnosis make?

A lot, Morris contends.

Without the new criteria, there is too much overlap between people with mild cognitive impairment (MCI), who are simply having trouble performing some daily tasks, and those with early stage Alzheimer's with mild dementia. Deciding whether a person is diagnosed with MCI or Alzheimer's is often "artificial and arbitrary," Morris writes in the current issue of the journal Archives of Neurology.

The result has been that people with MCI are unnecessarily prescribed drugs that are more appropriate for people with Alzheimer's because doctors "often do not distinguish the two conditions when faced with issues of medical management," Morris says.

The new criteria, writes Morris, allows for better patient care and a better way for doctors to categorize mild cognitive problems from early-stage Alzheimer's.