The effect of age and microstructural white matter integrity on XXXX time variation and fast-paced walking speed.

@entity1 @entity2806 @entity1315 @entity3813 @entity62 @entity528
UNASSIGNED: @entity62 ( @entity62 ) is associated with less uniform and slower walking in older adults. The effect of age and subclinical @entity528 (a potentially earlier phase of WM @entity2806 ) on walking patterns and speed is less clear. This study examines the effect of age on the associations of regional microstructural WM integrity with walking variability and speed, independent of macrostructural @entity62 . This study involved 493 @entity1 (n   =   51 young; n   =   209 young-old; n   =   233 old-old) from the Baltimore Longitudinal Study of Aging. All completed a 400-meter walk test and underwent a concurrent brain MRI with diffusion tensor imaging. Microstructural WM integrity was measured as fractional anisotropy (FA). Walking variability was measured as trend-adjusted variation in time over ten 40-meter laps ( @entity3813 time variation, LTV). Fast-paced walking speed was assessed as mean @entity3813 time (MLT). Multiple linear regression models of FA predicting LTV and MLT were adjusted for age, sex, height, weight, and WM hyperintensities. Independent of WM hyperintensities, lower FA in the body of the corpus callosum was associated with higher LTV and longer MLT only in the young-old. Lower FA in superior longitudinal, @entity1315 , the anterior limb of the internal capsule, and the anterior corona radiate was associated with longer MLT only in the young-old. While macrostructural @entity62 is known to predict more variable and slower walking in older adults, microstructural WM disruption is independently associated with more variable and slower fast-paced walking only in the young-old. Disrupted regional WM integrity may be a subclinical contributor to abnormal walking at an earlier phase of aging.
