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“Harmless” Condition Alters Brain Function in Elderly
According to a statement issued on August 13 by the Radiological Society of North America (RSNA), researchers at the Mayo Clinic have discovered that a common condition called leukoaraiosis, made up of tiny areas in the brain that have been deprived of oxygen and appear as bright white dots on magnetic resonance imaging (MRI) scans, is not a harmless part of the aging process, but rather a disease that alters brain function in the elderly.
Results of the study were published online in Radiology.
Leukoaraiosis (also called small-vessel ischemia) is a condition in which diseased blood vessels lead to small areas of damage in the white matter of the brain. The lesions are common in the brains of people over the age of 60, although the amount of disease varies among individuals. The researchers performed functional MRI (fMRI) scans on cognitively normal elderly participants recruited from the Mayo Clinic Study of Aging between 2006 and 2010. In 18 participants, the amount of leukoaraiosis was a moderate 25 mL, compared with less than 5 mL in 18 age-matched control participants.
The subjects were imaged in an MRI scanner as they performed a semantic decision task that involved identifying word pairs and a visual perception task that involved differentiating straight from diagonal lines. fMRI is a special type of magnetic resonance imaging that measures metabolic changes in an active part of the brain.
Although both groups performed the tasks with similar success, the fMRI scans revealed different brain activation patterns between the two groups. Compared with members of the control group, patients with moderate levels of leukoaraiosis had atypical activation patterns, including decreased activation in areas of the brain involved in language processing during the semantic decision task and increased activation in the visual-spatial areas of the brain during the visual perception task.
The researchers concluded that leukoaraiosis is not a benign manifestation of aging but an important pathologic condition that alters brain function.
For more information, visit the RSNA Web site.