Article

Step length variability (SLV) increases with age in those without overt
neurologic disease, is higher in neurologic patients, is associated with falls,
and predicts dementia. Whether higher SLV in older adults without neurologic
disease indicates presence of neurologic abnormalities is unknown. Our objective
was to identify whether SLV in older adults without overt disease is associated
with findings from multimodal neuroimaging. A well-characterized cohort of 265
adults (79-90 years) was concurrently assessed by gait mat, magnetic resonance
imaging with diffusion tensor, and neurological exam. Linear regression models
adjusted for gait speed, demographic, health, and functional covariates assessed
associations of MRI measures (gray matter volume, white matter hyperintensity
volume, mean diffusivity, fractional anisotropy) with SLV. Regional distribution
of associations was assessed by sparse partial least squares analyses. Higher SLV
(mean: 8.4, SD: 3.3) was significantly associated with older age, slower gait
speed, and poorer executive function and also with lower gray matter integrity
measured by mean diffusivity (standardized beta=0.16; p=0.02). Associations
between SLV and gray matter integrity were strongest for the hippocampus and
anterior cingulate gyrus (both beta=0.18) as compared to other regions.
Associations of SLV with other neuroimaging markers were not significant. Lower
integrity of normal-appearing gray matter may underlie higher SLV in older
adults. Our results highlighted the hippocampus and anterior cingulate gyrus,
regions involved in memory and executive function. These findings support
previous research indicating a role for cognitive function in motor control.
Higher SLV may indicate focal neuropathology in those without diagnosed
neurologic disease.
CI - Copyright (c) 2014 Elsevier B.V. All rights reserved.

Langue : ANGLAIS