Clinical Status Affects MRI Measures' Ties to Cognition

Associations are stronger in subjects without dementia, do not vary by race

FRIDAY, April 16 (HealthDay News) -- The associations of magnetic resonance imaging (MRI) measures with cognition vary according to subjects' clinical status -- with stronger associations seen among those without dementia -- but they do not differ by race, according to a study published in the April issue of the Archives of Neurology.

Neelum T. Aggarwal, M.D., of the Rush University Medical Center in Chicago, and colleagues conducted a study of 575 participants from a biracial population participating in the Chicago Health and Aging Project. Study participants underwent MRI with measurement of white matter hyperintensity volume (WMHV), total brain volume (TBV) and cerebral infarcts, as well as detailed neuropsychological testing, including assessments of both global cognition and five distinct cognitive domains.

The researchers found that overall, and among those without dementia, cognition was positively associated with TBV and inversely associated with WMHV and number of infarcts, although with all three measures simultaneously added to the model, the association with number of infarcts was no longer significant. Among subjects without dementia, all three of the MRI measures were associated with performance in several cognitive domains, particularly perceptual speed. Among subjects with dementia, only TBV was associated with cognition. Race did not significantly change any of these associations.

"Consistent with a previous study, the association of each MRI measure with cognitive function was similar between African-Americans and whites. Despite differences in baseline cognitive test results that persisted after controlling for educational achievement, both groups showed similar associations between cognitive performance and MRI pathological measures, suggesting that race itself does not modify the association of MRI measures with cognitive function," the authors write.

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