TY - JOUR
T1 - Lower gray matter integrity is associated with greater lap time variation in high-functioning older adults
AU - Tian, Qu
AU - Resnick, Susan M.
AU - Landman, Bennett A.
AU - Huo, Yuankai
AU - Venkatraman, Vijay K.
AU - Gonzalez, Christopher E.
AU - Simonsick, Eleanor M.
AU - Shardell, Michelle D.
AU - Ferrucci, Luigi
AU - Studenski, Stephanie A.
N1 - Publisher Copyright:
© 2015.
PY - 2016/5/1
Y1 - 2016/5/1
N2 - Background: Lower integrity of cerebral gray matter is associated with higher gait variability. It is not known whether gray matter integrity is associated with higher lap time variation (LTV), a clinically accessible measure of gait variability, high levels of which have been associated with mortality. This study examines the cross-sectional association between gray matter mean diffusivity (MD) and LTV in community-dwelling older adults. Methods: Study participants consisted of 449 high-functioning adults aged 50 and older (56.8% female) in the Baltimore Longitudinal Study of Aging, free of overt neurological disease. The magnitude of MD in the gray matter, a measure of impaired tissue integrity, was assessed by diffusion tensor imaging in 16 regions of interest (ROIs) involved with executive function, sensorimotor function, and memory. LTV was assessed as variability in lap time based on individual trajectories over ten 40-m laps. Age, sex, height, and weight were covariates. The model additionally adjusted for mean lap time and health conditions that may affect LTV. Results: Higher levels of average MD across 16 ROIs were significantly associated with higher LTV after adjustment for covariates. Specifically, higher MD in the precuneus and the anterior and middle cingulate cortices was strongly associated with higher LTV, as compared to other ROIs. The association persisted after adjustment for mean lap time, hypertension, and diabetes. Conclusions: Lower gray matter integrity in selected areas may underlie greater LTV in high-functioning community-dwelling older adults. Longitudinal studies are warranted to examine whether changes in gray matter integrity precede more variable gait.
AB - Background: Lower integrity of cerebral gray matter is associated with higher gait variability. It is not known whether gray matter integrity is associated with higher lap time variation (LTV), a clinically accessible measure of gait variability, high levels of which have been associated with mortality. This study examines the cross-sectional association between gray matter mean diffusivity (MD) and LTV in community-dwelling older adults. Methods: Study participants consisted of 449 high-functioning adults aged 50 and older (56.8% female) in the Baltimore Longitudinal Study of Aging, free of overt neurological disease. The magnitude of MD in the gray matter, a measure of impaired tissue integrity, was assessed by diffusion tensor imaging in 16 regions of interest (ROIs) involved with executive function, sensorimotor function, and memory. LTV was assessed as variability in lap time based on individual trajectories over ten 40-m laps. Age, sex, height, and weight were covariates. The model additionally adjusted for mean lap time and health conditions that may affect LTV. Results: Higher levels of average MD across 16 ROIs were significantly associated with higher LTV after adjustment for covariates. Specifically, higher MD in the precuneus and the anterior and middle cingulate cortices was strongly associated with higher LTV, as compared to other ROIs. The association persisted after adjustment for mean lap time, hypertension, and diabetes. Conclusions: Lower gray matter integrity in selected areas may underlie greater LTV in high-functioning community-dwelling older adults. Longitudinal studies are warranted to examine whether changes in gray matter integrity precede more variable gait.
KW - Diffusion tensor imaging
KW - Gray matter integrity
KW - High-functioning older adults
KW - Lap time variation
KW - Mean diffusivity
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U2 - 10.1016/j.exger.2016.02.009
DO - 10.1016/j.exger.2016.02.009
M3 - Article
C2 - 26899565
AN - SCOPUS:84959010961
SN - 0531-5565
VL - 77
SP - 46
EP - 51
JO - Experimental Gerontology
JF - Experimental Gerontology
ER -