Lower Thalamic Blood Flow Is Associated With Slower Stride Velocity in Older Adults

Noah D Koblinsky; Sarah Atwi; Ellen Cohen; Nicole D Anderson; Carol E Greenwood; Bradley J MacIntosh; Andrew D Robertson

doi:10.3389/fnagi.2020.571074

Lower Thalamic Blood Flow Is Associated With Slower Stride Velocity in Older Adults

Front Aging Neurosci. 2020 Sep 18:12:571074. doi: 10.3389/fnagi.2020.571074. eCollection 2020.

Authors

Noah D Koblinsky^{1

2}, Sarah Atwi^{2

3

4}, Ellen Cohen^{2

3

5}, Nicole D Anderson^{1

6}, Carol E Greenwood^{1

7}, Bradley J MacIntosh^{2

3

4}, Andrew D Robertson^{2

3}

Affiliations

¹ Rotman Research Institute, Baycrest Health Sciences, University of Toronto, Toronto, ON, Canada.
² Hurvitz Brain Sciences, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.
³ Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.
⁴ Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.
⁵ Department of Physical Therapy, University of Toronto, Toronto, ON, Canada.
⁶ Departments of Psychology and Psychiatry, University of Toronto, Toronto, ON, Canada.
⁷ Department of Nutritional Sciences, University of Toronto, Toronto, ON, Canada.

Abstract

Background: Gait deficits are associated with brain atrophy and white matter hyperintensities (WMH) - both markers of underlying cerebral small vessel disease (SVD). Given reduced subcortical cerebral blood flow (CBF) is prevalent in SVD, we tested the hypothesis that regional CBF is positively associated with gait performance among older adults.

Methods: Thirty-two older adults (55-80 years) with at least one vascular risk factor were recruited. We assessed gait during 2 consecutive walking sequences using a GAITRite system: (1) at a self-selected pace, and (2) while performing a serial subtraction dual-task challenge. We quantified CBF using pseudo-continuous arterial spin labeling MRI within 4 regions of interest: putamen, pallidum, thalamus, and hippocampus. We investigated associations between gait characteristics and overall CBF adjusting for age, sex, and height in an omnibus approach using multivariate analysis of variance, followed by regression analysis with each individual region. We also conducted further regression analyses to investigate associations between gait characteristics and frontal lobe CBF. Sensitivity analyses examined how the observed associations were modified by WMH, executive function, and depressive symptoms. A change of 10% in the model's adjusted r² and effect size was considered as a threshold for confounding.

Results: Overall subcortical CBF was not associated with self-paced gait. When examining individual ROI, gait velocity was directly related to thalamic CBF (p = 0.026), and across all gait variables the largest effect sizes were observed in relation to thalamic CBF. In the dual-task condition, gait variables were not related to CBF in either the omnibus approach or individual multiple regressions. Furthermore, no significant associations were observed between frontal CBF and gait variables in either the self-paced or dual-task condition. Sensitivity analyses which were restricted to examine the association of velocity and thalamic CBF identified a cofounding effect of depressive symptoms which increased the effect size of the CBF-gait association by 12%.

Conclusion: Subcortical hypoperfusion, particularly in regions that comprise central input/output tracts to the cortical tissue, may underlie the association between gait deficits and brain aging.

Keywords: arterial spin labeling; brain aging; gait; pallidum; putamen; thalamus.