LAUSR

OBJECTIVE Reactive stepping is critical for preventing falls and is impaired in people with multiple sclerosis (MS); however, which aspects of stepping relate to falls remain poorly understood. Identifying outcomes most related to falls is a first step toward improving rehabilitation for fall prevention. The purpose of this study was to assess whether reactive step latency or length during forward and backward losses of balance were related to a history of falls in people with MS. METHODS Of the 112 people with MS who participated in this study, 76 reported no falls in the previous 6 months, whereas 36 reported 1 or more falls. Participants completed 3 forward and 3 backward treadmill-induced reactive steps from stance. Step length (centimeters) and step latency (milliseconds) were measured using motion capture and analyzed via MATLAB. RESULTS Participants with a history of falls had significantly slower step latencies during backward stepping but not forward stepping than those without a history of falls. Step length did not differ between groups. Slower step latencies during backward stepping significantly increased the odds of having experienced a fall (β = .908, SE = 0.403, OR = 2.479, 95% CI = 1.125-5.464). CONCLUSION People with MS and a history of falling show delayed step onsets during backward reactive stepping. Specifically, for every 10 milliseconds increase in step latency, people with MS were 2.5 times more likely to have a fall history. Although clinical trials are necessary to determine whether interventions targeting reactive stepping reduce falls in people with MS, the current work indicates that the latency of steps may be a relevant target for this work. IMPACT Subsequent fall prevention clinical trials should consider targeting backward reactive step latency to further assess its relevance for rehabilitation in people with MS.