Checkup

A Clearer Understanding

Improving the Accuracy of Dementia Diagnoses in African-Americans

Dr. John Lucas

There's good news for African-Americans and the neurologists who treat them.

New standards that should lead to more accurate diagnoses of Alzheimer's disease and other forms of dementia in older African-Americans have been developed by a group of Mayo Clinic doctors in Jacksonville. These updated sets of normative standards for neuropsychological testing should help doctors better understand cognitive function in older African-Americans.

"Up until now, we've been comparing older African-American patients to normative groups comprised mostly of Caucasians," says Mayo Clinic neuropsychologist Dr. John Lucas. "They did not share the same background, particularly the same educational experiences. As a result, currently existing norms for a number of commonly used tests often exaggerate the frequency and severity of cognitive impairment in African-Americans."

Lucas and his colleagues in Mayo's Alzheimer's Disease Research Center (funded by the National Institute on Aging) designed a study to determine what constitutes normal memory and cognition for older African-Americans raised and educated in the South during segregation.

"At that time, there were a host of differences in the educational systems between the Caucasian and African-American communities," he says. "We know that education has a strong effect on a person's test scores, and therefore any systematic differences in education must be accounted for when designing test procedures and evaluating test results. Most dementia tests can account for differences in the number of years of education someone completed. But they don't address other potential differences in education that existed between Caucasians and African-Americans before desegregation."

Dr. Floyd Willis

Dr. Floyd Willis is a Mayo Clinic family practice physician with an interest in racial disparities in health care. He says using normative standards developed for a dissimilar group of people can lead to telling some people they have dementia when they do not. In some cases, this can exclude them from early interventional treatments; in others, it doesn't allow early detection of memory loss.

Lucas, Willis and their collaborators published their normative standards, which resulted from their eight-year research project, in the May 2005 issue of The Clinical Neuropsychologist. Their final sample included data from 309 African-American volunteers between the ages of 56 and 94 from the Jacksonville area.

As important as their work will be in accurately diagnosing dementia, Lucas acknowledges the new normative standards won't necessarily be universally applied to all African-Americans.

"It's really going to be up to the clinician to decide," he says. "The importance of these norms lies in their ability to characterize normal memory functioning in a large segment of the African-American community who shared similar, disadvantaged educational opportunities. The appropriate use of these norms will not only help us identify memory problems when they are present, but they will help avoid misdiagnosing memory impairment in normal patients."

To explore this line of research further, Lucas and investigators from five universities around the country are putting together a consortium grant for a study of cognitive function in older African-Americans. The sample will include people from different regions of the country and both rural and urban locations.

Willis currently is conducting a pilot study on early memory loss that he hopes to expand. He's recruiting African-Americans older than 70 who have a memory complaint or believe their memory is not as good as that of friends their age.

"This project, and my great interest, is to characterize a group of African-Americans with early memory loss and look at their vascular risk, " he says. "In African-Americans, as opposed to Caucasians, it is very possible that early memory loss will be associated more with vascular risk factors and small strokes as opposed to Alzheimer's disease. We are in search of this information."