Brain Damage Seen on MR Scans May Predict Memory Loss in Old Age

Researchers tested 679 people age 65 and older without dementia for mild cognitive impairment, the stage between normal aging and dementia. Participants underwent magnetic resonance imaging (MRI) brain scanning where the investigators looked for small areas of brain damage called white matter hyperintensities, often referred to as ministrokes. They also looked for infarcts, or areas of dead tissue typically called strokes. Both types of brain damage may be caused by vascular disease in the brain.

The study revealed that individuals with white matter hyperintensities were nearly twice as likely to have mild cognitive impairment that included memory loss. However, individuals who had infarcts on their brain scans were more apt to experience mild cognitive impairment in abilities other than memory loss.

The results remained the same regardless of a person's age, gender, ethnic group, education, and if they had a gene thought to be a strong risk factor for dementia, called the ApoEe4 gene. "The most interesting finding in this study was that white matter hyperintensities, or ministrokes, predicted memory problems, while strokes predicted nonmemory problems,” said study author José Luchsinger, M.D., MPH, from Columbia University Medical Center (New York, USA). "Traditionally, ministrokes and strokes are thought to have a common origin and to more strongly predict nonmemory cognitive problems. There are an increasing number of studies challenging the idea that all white matter hyperintensities are similar to strokes. The fact that white matter hyperintensities more strongly predicted memory problems could challenge traditional views that white matter hyperintensities are milder versions of stroke that are produced only by conditions such as high blood pressure,” said Dr. Luchsinger.

Dr. Luchsinger reported that more research is needed to understand white matter hyperintensities and to identify which are related to stroke and which are related to other conditions such as Alzheimer's disease. He reported that this could eventually help clincians and researchers to design preventive strategies for memory and other types of cognitive impairment.

The study was published in the August 11, 2009, issue of Neurology, the journal of the American Academy of Neurology.

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