Evaluating Intrinsic Fall Risk Factors After Incomplete Spinal Cord Injury: Distinguishing Fallers From Nonfallers.

OBJECTIVE: To determine whether performance on measures of lower extremity muscle strength, sensory function, postural control, gait speed, and balance self-efficacy could distinguish fallers from nonfallers among ambulatory individuals with spinal cord injury or disease (SCI/D). DESIGN: Prospective cohort study. SETTING: Community. PARTICIPANTS: Individuals (N=26; 6 female, aged 58.9±18.2y) with motor incomplete SCI/D (American Spinal Injury Association Impairment Scale rating C [n=5] or D [n=21]) participated. Participants were 7.5±9.1 years post injury. Seventeen participants experienced traumatic causes of spinal cord injury. MAIN OUTCOME MEASURES: Participants completed laboratory-based and clinical measures of postural control, gait speed, balance self-efficacy, and lower extremity strength, as well as proprioception and cutaneous pressure sensitivity. Participants were then followed for up to 1 year to track falls using a survey. The survey queried the circumstances and consequences of each fall. If a participant's number of falls equaled or exceeded the median number of falls experience by all participants, they were classified a faller. RESULTS: Median follow-up duration was 362 days and median time to first fall was 60.5 days. Fifteen participants were classified as fallers. Most falls occurred during the morning or afternoon (81%), at home (75%), and while walking (47%). The following laboratory-based and clinical measures distinguished fallers from nonfallers (P<.05): measures of lower extremity strength, cutaneous pressure sensitivity, walking speed, and center of pressure velocity in the mediolateral direction. CONCLUSIONS: There are laboratory-based and clinical measures that can prospectively distinguish fallers from nonfallers among ambulatory individuals with spinal cord injury. These findings may assist clinicians when evaluating their patients' fall risk.

Investigating proactive balance control in individuals with incomplete spinal cord injury while walking on a known slippery surface.

BACKGROUND: Up to 83 % of individuals with incomplete spinal cord injury (iSCI) experience ≥ 1 fall/year. Individuals with iSCI employ more cautious walking strategies than able-bodied (AB) individuals during normal walking. Whether individuals with iSCI can use proactive balance strategies to adapt to expected slip perturbations/reduce slip severity while walking has not been previously assessed. METHODS: 19 individuals with iSCI (AIS D; 14 males; 61 ± 18 years) and 17 AB individuals (13 males; 61 ± 18 years) completed 3 walking conditions: normal walking trials, an unexpected slip trial, and expected slip trials. Steel rollers induced a slip in the antero-posterior (AP) direction. Outcome variables included step length, center of mass velocity, foot-floor angle, AP margin of stability, and maximum post-slip velocity (PSV). RESULTS: The iSCI group used a greater magnitude of cautious strategies (i.e. walking slower with shorter, flatter steps) than AB individuals in all conditions. However, the lack of significant interaction effects indicate that the proactive adaptations compared to normal walking (i.e. walking slower with shorter, flatter steps, and a more anterior xCOM-position) were similar between the two groups (AB & iSCI). Both groups showed a similar rate of adaptation (after just 1 slip) and these feedforward changes were maintained throughout the remaining slip trials which was effective at reducing maximum PSV. CONCLUSIONS: Individuals with iSCI use proactive balance strategies to adapt to a known slippery surface in a similar manner to AB individuals both in terms of the proportion and timing of adaptation.

Are there attentional demands associated with haptic modalities while walking in young, healthy adults?

STUDY DESIGN: A prospective, observational study. OBJECTIVES: To assess the attentional demands of using haptic modalities during walking using a multi-task paradigm in young, healthy adults. SETTING: Biomechanics of Balance and Movement (BBAM) Lab, University of Saskatchewan. METHODS: Twenty-two (12 male) young, healthy adults performed walking trials with and without a verbal reaction time (VRT) task, as well as with and without the use of haptic anchors and light touch on a railing. Walking performance was evaluated using normalized stride velocity and step width, and dynamic stability was evaluated using step width variability and medial-lateral margin of stability (ML MOS) and its variability. RESULTS: There were no significant differences in VRT when walking with and without added haptic input and no interactions between the added VRT task and added haptic input. Step width increased and variability of the ML MOS increased during trials with the VRT task compared to trials without the VRT task. The ML MOS decreased when using both haptic tools with a greater decrease when using light touch on the railing compared to when using the haptic anchors. Normalized stride velocity and step width decreased when using light touch on the railing only. CONCLUSION: Both haptic tools affected stability during walking. Using the railing to add haptic input had a greater effect on walking stability and was the only haptic tool to affect walking performance. Attentional demands should be considered in future research and applications of adding haptic input during walking.