Computer Test Accurately Detects Early Alzheimer's

By Karla Gale

NEW YORK (Reuters Health) - Researchers have developed a more accurate version of a standard test to detect dementia and cognitive impairment that takes only about 10 minutes to administer, according to a report in the Proceedings of the National Academy of Sciences.

The standard scoring method for dementia, known as the "National Institute of Aging's Consortium to Establish a Registry for Alzheimer's Disease's 10-word list" (CWL), consists of three immediate-recall trials of a 10-word list, followed by an interference task, and then a delayed-recall trial of the word list.

"In the traditional scoring and interpretation, only the total score from the fourth trial is usually used," lead author Dr. William R. Shankle explained to Reuters Health. However, much more information can be gleaned from analyzing the patterns of words recalled based on their placement in the list.

"The method we describe -- the mental skills test -- uses the individual responses to every item in all four trials to come up with an answer," the researcher added.

The mental skills test takes about 10 minutes to administer online. Once the answers are submitted, a formula is used to calculate the final score that within seconds "indicates if a person is impaired or not with an overall accuracy 97 percent," Shankle said.

Shankle and colleagues at the University of California, Irvine, evaluated 471 community-dwelling subjects using the interview-based Clinical Dementia Rating Scale. They then compared results of the standard CWL test and the mental skills test.

For differentiating mild cognitive impairment from normal aging, the shorter mental skills test was more sensitive in detecting impaired subjects than was the longer CWL total delayed-recall test. According to the authors, their review of the literature showed their procedure to have a higher reported sensitivity than any other published test results.

"Early detection is absolutely critical because current treatments are all geared to slow the accumulation of beta amyloid," Shankle noted. With earlier treatment, "many patients can live out the rest of their life with no impairment or only minimal impairment."

Just by eliminating the need for institutionalization, he added, the cost of care can be reduced by $160,000 per patient.

SOURCE: Proceedings of the National Academy of Science, March 29, 2005.