Gait Speed and Gait Variability Are Associated with Different Functional Brain Networks.

Junhong Zhou,Brad Manor,On-Yee Lo,Lewis A. Lipsitz,Mark A. Halko,Rachel Harrison

doi:10.3389/fnagi.2017.00390

Abstract

Gait speed and gait variability are clinically meaningful markers of locomotor control that are suspected to be regulated by multiple supraspinal control mechanisms. The purpose of this study was to evaluate the relationships between these gait parameters and the functional connectivity of brain networks in functionally limited older adults. Twelve older adults with mild-to-moderate cognition “executive” dysfunction and relatively slow gait, yet free from neurological diseases, completed a gait assessment and a resting-state fMRI. Gait speed and variability were associated with the strength of functional connectivity of different brain networks. Those with faster gait speed had stronger functional connectivity within the frontoparietal control network (R = 0.61, p = 0.04). Those with less gait variability (i.e., steadier walking patterns) exhibited stronger negative functional connectivity between the dorsal attention network and the default network (R = 0.78, p < 0.01). No other significant relationships between gait metrics and the strength of within- or between- network functional connectivity was observed. Results of this pilot study warrant further investigation to confirm that gait speed and variability are linked to different brain networks in vulnerable older adults.

Highlights

Age-related decline in locomotor control often leads to falls and adversely affects one’s quality of life and independence
This study examined the relationship among two common metrics of locomotor control and the functional connectivity of established large-scale brain networks in older adults with slow gait and executive dysfunction
The results suggest that gait speed and variability were associated with separate functional brain networks: gait speed was correlated with the strength of functional connectivity within the frontoparietal control network, whereas gait stride time variability was correlated with the strength of anti-phase functional connectivity between the dorsal attention network and the default network

Summary

Introduction

Age-related decline in locomotor control often leads to falls and adversely affects one’s quality of life and independence. Locomotor control is most commonly assessed by measuring average preferred gait speed and/or gait variability (i.e., the degree of steadiness about the average of a given stride parameter over consecutive strides). These two metrics are often uncorrelated (Hollman et al, 2011; Lord et al, 2013) and may be independently influenced by experimental stressors (Hausdorff, 2005, 2007). The relationships between metrics of gait and brain function during walking have been challenging to establish primarily because current neuroimaging tools are sensitive to head and body movements (Hamacher et al, 2015; Wittenberg et al, 2017). Resting-state functional magnetic resonance imaging (rs-fMRI) is a powerful tool that enables estimation of functional organization within the brain (Biswal et al, 1995; van den Heuvel and Pol, 2010) and subsequently, determination of how this organization is linked with function and behavior

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