Foot placement variability as a walking balance mechanism post-spinal cord injury

Abstract

Background Spinal cord injury affects walking balance control, which necessitates methods to quantify balance ability. The purposes of this study were to 1) examine walking balance through foot placement variability post-injury; 2) assess the relationship between measures of variability and clinical balance assessments; and 3) determine if spatial parameter variability might be used as a clinical correlate for more complex balance measurements. Methods Ten persons with spinal cord injury walked without devices on a split-belt treadmill at self-selected speeds. Ten healthy controls walked at 0.3 and 0.6 m/s for comparison. Variability of step width and length, anteroposterior and mediolateral foot placements relative to center-of-mass, and margin-of-stability were calculated. Clinical assessments included Berg Balance Scale and Dynamic Gait Index. Findings Participants with spinal cord injury demonstrated significantly different variability in all biomechanical measures compared to controls (P≤0.007). Berg Balance Scale scores were significantly inversely associated with step length as well as anteroposterior and mediolateral foot placement variability (P≤0.05). Dynamic Gait Index scores were significantly inversely associated with mediolateral foot placement variability (P≤0.05). Participants with spinal cord injury showed significant correlations between spatial parameter variability and all other measures (P≤0.005), except between step length and margin-of-stability (P=0.068); controls revealed fewer correlations. Interpretation Persons post-spinal cord injury exhibit an abnormal amount of stepping variability when challenged to walk without devices, yet preserve the ability to avoid falling. When complex laboratory measures of variability are unavailable clinically, spatial parameter variability or standardized balance assessments may be plausible indicators of walking balance control.

Relationships between frontal-plane angular momentum and clinical balance measures during post-stroke hemiparetic walking

“…Since margin of stability has not been reported in the stroke population, previous comparisons have not been made with angular momentum-based measures. However, research in walking after spinal cord injury suggests that person with poor balance likely had increased margin of stability relative to control subjects walking at a matched speed [30]. Thus, it appears that relationships do exist between margin of stability and changes in H, BBS and DGI (i.e., higher margin of stability would be associated with higher change in H and lower clinical balance measures).…”

Non-linear dynamics of human locomotion: effects of rhythmic auditory cueing on local dynamic stability

“…As illustrated in Figure 1 and in the online movie (supplementary material), small deviations in the trajectory is evident from one stride to the next, which are likely linked to the continuous adjustments that the motor control performs to maintain stable gait. Other authors have used the center of pressure in gait stability studies (Day et al, 2012), for instance to analyze how motor control reacts to large external perturbations (Hof et al, 2010). The center of pressure trajectory seems therefore a relevant parameter, from which LDS can be computed.…”

Gait Variability and Multiple Sclerosis

“…However, more recently, evidence has demonstrated meaningful characteristics of gait variability, associated with neural control of walking [1, 2, 9, 10]. Increases in gait variability have been observed in individuals with advanced age [11–14] as well as various neurologically impaired populations, including spinal cord injury [15] and neurological conditions, such as Parkinson's disease [16], dementia [17], and multiple sclerosis [18]. Gait variability has further been associated with motor control function [9, 19], energetic cost of walking [20], and falls [12–14] in various populations.…”