n elderly woman goes to a neuropsychologist to get her memory tested for possible dementia. As part of the assessment, the neuropsychologist asks her to identify line drawings of objects, such as a French horn or a microscope. If she is unable to name the item, it could be because early Alzheimers disease may have impaired her ability to retrieve the right word. Or, she may have difficulty naming the items because of the quality of her education and perhaps the culture in which she was raised. Is the woman a candidate for dementia if she cannot recognize a French horn?
Although a diagnosis is never based on one image-recognition test, this example emphasizes that cultural bias in neuropsychological tests can lead to ambiguous and even skewed results. African Americans, for example, tend to score lower on these tests than whites even if both groups have attained the same number of years of schooling. Because of lower scores, healthy African Americans may be more likely to be misdiagnosed with Alzheimers and other cognitive deficits.
Clearly, the number of years in school cannot account for why healthy African Americans do not perform as well as whites on these neuropsychological tests. So Columbia Health Sciences researchers decided to study whether quality, rather than quantity, of education could help explain the lower test scores among African Americans.
In the study, the investigators measured quality of schooling by administering a reading test to 384 elderly African Americans and whites from Northern Manhattan. The researchers found they could eliminate most of the racial differences found in the neuropsychological test assessments by factoring in scores from the reading tests. Both African Americans and whites with a poor reading test result achieved similar neuropsychological scores.
The findings suggest that including an assessment of reading skills will help neuropsychologists know what scores to expect from elders with diverse educational backgrounds, says Dr. Jennifer Manly, assistant professor of neuropsychology in the cognitive neuroscience division of the Taub Institute for Research on Alzheimers Disease and the Aging Brain and lead author of the study. Incorporating reading tests into our testing battery could help reduce misdiagnosis of cognitive impairment among people with low reading levels regardless of race. The findings were published in the March issue of the Journal of the International Neuropsychological Society.
Dr. Manlys study assessed 192 African Americans and 192 non-Hispanic whites who did not suffer from dementia. The participants, who were 65 years of age and older and were functioning normally in their daily lives, were drawn from the Washington Heights-Inwood Columbia Aging Project, a 10-year-old epidemiological study of cognitive aging and dementia that currently includes about 2,800 people and is led by Dr. Richard Mayeux, professor of neurology and psychiatry, director of the Gertrude H. Sergievsky Center, and co-director of the Taub Institute.
The study participants took a battery of neuropsychological tests that examined memory, abstract reasoning, spatial skills, and the ability to name objects from drawings. The reading test required participants to pronounce words of increasing difficulty from a list. The participants who had a better quality of education were better able to pronounce the more uncommon words. On average, African Americans in the study population scored worse than whites on the reading tests because the reading test reflects the poor educational experience of many African American elders.
Dr. Manly suggests that segregated schooling, shorter school years, and limited funding devoted to African American schools in the 1920s and 1930s explain the poorer quality of education for the African Americans in the study. Many elderly African Americans, now living in New York, were educated in the rural South where state school boards mandated shorter school years.
But Dr. Manlys findings extend beyond African Americans. Testing reading as part of neuropsychological assessment could help clinicians improve their accuracy of diagnosis of dementia or cognitive deficits among whites or other ethnic groups who had a poor education.
As a result of the research findings, Columbia researchers are now adding reading tests to their assessment of cognitive ability in the aging project, looking to see how accounting for quality of education might affect previous findings on levels of cognitive performance and rates of dementia in the community.
Dr. Manly is also validating the idea that a reading test could be an estimate of quality of education by analyzing the educational experience of the study participants. She is collecting data on expenditures per student, teacher salaries, student-teacher ratios, and school year length to check for a correlation with reading levels.
Dr. Manly also plans to follow study participants to determine who develops dementia and if reading abilities are affected. If reading levels remain the same before and after dementia, the reading test could replace length of education as the standard for measuring educational experience.
Even without the validation, her findings are pushing the field of neuropsychology. Dr. Manly has shown that by accounting for just one indicator of educational quality, racial differences on cognitive test performance in older people are significantly reduced, says Dr. Molly Wagster, program director for neuropsychology of aging research at the National Institute on Aging, the major supporter of the research. This very important work will help guide the development of tests that are more culturally relevant and more accurate.
The Alzheimers Association and the New York City Speakers Fund for Biomedical Research also provided funding for the study.
Dr. Manly hopes the paper and others like it eventually will help people with dementia and those at risk of developing it. Maybe measuring educational and cultural experiences will reduce the tendency in some cognitive research to put such an emphasis on race, Dr. Manly says.