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Cognitive impairment worse than expected in seniors, says University of Pittsburgh study

Archives of Neurology article finds that 22 percent of the population over age 75 have cognitive disorders, worse than those expected for normal aging

University of Pittsburgh Medical Center

PITTSBURGH, Oct. 20 - The rate of mild cognitive impairment (MCI) in persons aged 75 and older is higher than expected, affecting 22 percent of those in the age group, according to two articles published in Archives of Neurology, one of the JAMA/Archives journals, and authored by Oscar Lopez, M.D., associate professor of neurology at the University of Pittsburgh.

Dr. Lopez's research involved 3,608 people aged 75 and older who participated in the Cardiovascular Health Study (CHS). He found that the majority of cognitive difficulties are the result of multiple problems, such as small "silent" ischemic lesions in the brain, depression, use of psychiatric medications, or other disease processes that can affect the brain (including chronic liver and kidney failure) rather than the onset of Alzheimer's.

MCI is a heterogenous condition that affects the areas of the brain that process memory and language and the areas that help keep attention and focus.

"We were surprised at how prevalent the condition was and how other medical conditions increased people's risk to have MCI," Dr. Lopez said. "This emphasizes the importance of good medical care in preventing the development of brain disease."

According to Dr. Lopez, MCI can be the result of many factors. Among them are the presence of the Apolipoprotein E4 alelle, which has been identified as a risk factor for Alzheimer's disease; race, MCI is more prevalent in African-Americans; and "silent" strokes.

"It is important to note that African Americans have more cardiovascular disease and cerebrovascular disease risk factors than whites, which may explain the increased prevalence of MCI in this group of subjects," Dr. Lopez said.

Dr. Lopez and his team examined 3,608 patients over age 75 who underwent detailed neurological, neuropsychological, neuroradiational (MRI scans) and psychiatric testing to identify dementia and MCI. The CHS was one of the largest single epidemiological studies conducted in the United States, begun in 1987 by Lewis Kuller, M.D., professor of epidemiology in the Graduate School of Public Health at the University of Pittsburgh.

Dr. Lopez received his medical degree from the University of La Plata, Argentina, and he trained in neurology in Buenos Aires. Dr. Lopez completed a behavioral neurology fellowship at the University of Pittsburgh in 1990. He has a broad interest in behavioral neurology, neuropsychiatry and dementia. Dr. Lopez is currently developing in vivo models of HIV-dementia and Alzheimer's disease using positron emission tomography technology and magnetic resonance imaging.

Also participating in the study from the University of Pittsburgh was Steven T. DeKosky, M.D., professor of neurology and psychiatry and director of the Alzheimer's Disease Research Center, and James T. Becker, M.D., professor of psychiatry, neurology and psychology.

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