Differential deficits in spatial and temporal interlimb coordination during walking in persons with incomplete spinal cord injury.

Background: Returning to community walking remains a major challenge for persons with incomplete spinal cord injury (iSCI) due, in part, to impaired interlimb coordination. Here, we examined spatial and temporal features of interlimb coordination during walking and their associations to gait deficits in persons with chronic iSCI.

Research Question: Do deficits in spatial and temporal interlimb coordination correspond differentially to clinical indicators of walking performance in persons with iSCI?

Methods: Sixteen persons with chronic iSCI and eleven able-bodied individuals participated in this study. Participants walked at self-selected gait speeds along an instrumented walkway that recorded left and right step lengths and times. We quantified interlimb coordination in terms of normalized differences between left and right step lengths (spatial asymmetry index) and step times (temporal asymmetry index), as well as, gap and phase coordination indices. We then assessed the extent to which these indices independently associated with clinical measures of walking performance.

Results: Participants with iSCI demonstrated greater spatial and temporal asymmetry, as well as, reduced gap and phase interlimb coordination as compared to age-matched controls (p < 0.001). We found no linear relationships between spatial and temporal asymmetry indices (p > 0.05) or between gap and phase coordination indices (p > 0.05). Spatial and temporal asymmetry indices weakly correlated with SCI-FAI composite scores (r = 0.26; p = 0.04). However, only spatial asymmetry indices strongly correlated with slower walking speed (r = 0.51; p < 0.002). We also found participants who used a hand-held assistive device (walker) demonstrated great spatial asymmetry as compared to those who did not (p < 0.03).

Significance: Differential impairments in spatial and temporal interlimb coordination correspond to overground walking deficits in persons with chronic iSCI. Spatial asymmetry associated with decreased walking speed and increased reliance on hand-held assistive devices. Gait training methods that target well-defined space and time domains of interlimb coordination may enhance overground gait training in persons with iSCI.