Gait variability is associated with subclinical brain vascular abnormalities in high-functioning older adults

Abstract

Background: Gait variability is an index of how much gait parameters, such as step length, change from one step to the next. Gait variability increases with age and in individuals affected by cortical and subcortical neurodegenerative conditions, and it is associated with falls and incident mobility disability. The brain anatomical correlates of gait variability have not been studied in high-functioning community-dwelling older adults.

Methods: Gait variability and brain MRIs were assessed in a cohort of 331 men and women (mean age = 78.3 years) free from stroke, dementia or Parkinson's disease. Gait variability was computed for spatial parameters (step length and step width) and for temporal parameters (stance time). Subclinical brain vascular abnormalities were measured on brain MRIs as infarcts and white matter hyperintensities.

Results: Greater variability of step length was associated with greater prevalence of infarcts, including infarcts in the basal ganglia, and with greater white matter hyperintensities severity, independent of age, gender, cognitive function and cardiovascular disease. Weaker associations were found between the other variability measures and the MRI measures.

Conclusion: In this group of older adults free from neurodegenerative diseases, a greater variability of step length was associated with greater burden of subclinical brain vascular abnormalities as defined by MRI.

(c) 2007 S. Karger AG, Basel.

Figures

Fig. 1.

Simplified diagram of the possible mechanisms controlling gait variability. Some degree of gait variability commonly accompanies gait. Boxes shaded in gray indicate the conditions that may cause increased gait variability and its consequences. PNS = Peripheral nervous system.

Fig. 2.

Diagram showing the most salient measures of gait for the left foot. Step time: the time to cover 1 step length. Step length: the distance between the heel strike of 1 foot to the heel strike of the opposite foot. Stance time: the time spent with 1 foot on the ground (from heel strike to toe off). Step width (not shown): the distance between the innermost boundaries of 2 consecutive steps.