Overground walking patterns after chronic incomplete spinal cord injury show distinct response patterns to unloading

Christopher Schmidt Easthope,Georg Rauter,Luca Renato Traini,Lea Awai,Armin Curt,Marc Bolliger,Martina Franz

doi:10.1186/s12984-018-0436-1

Abstract

BackgroundBody weight support (BWS) is often provided to incomplete spinal cord injury (iSCI) patients during rehabilitation to enable gait training before full weight-bearing is recovered. Emerging robotic devices enable BWS during overground walking, increasing task-specificity of the locomotor training. However, in contrast to a treadmill setting, there is little information on how unloading is integrated into overground locomotion. We investigated the effect of a transparent multi-directional BWS system on overground walking patterns at different levels of unloading in individuals with chronic iSCI (CiSCI) compared to controls.MethodsKinematics of 12 CiSCI were analyzed at six different BWS levels from 0 to 50% body weight unloading during overground walking at 2kmh− 1 and compared to speed-matched controls.ResultsIn controls, temporal parameters, single joint trajectories, and intralimb coordination responded proportionally to the level of unloading, while spatial parameters remained unaffected. In CiSCI, unloading induced similar changes in temporal parameters. CiSCI, however, did not adapt their intralimb coordination or single joint trajectories to the level of unloading.ConclusionsThe findings revealed that continuous, dynamic unloading during overground walking results in subtle and proportional gait adjustments corresponding to changes in body load. CiSCI demonstrated diminished responses in specific domains of gait, indicating that their altered neural processing impeded the adjustment to environmental constraints. CiSCI retain their movement patterns under overground unloading, indicating that this is a viable locomotor therapy tool that may also offer a potential window on the diminished neural control of intralimb coordination.

Highlights

Body weight support (BWS) is often provided to incomplete spinal cord injury patients during rehabilitation to enable gait training before full weight-bearing is recovered
In comparison to clinical reference values [54], tibial sensory evoked potentials (SEP) (46 ± 5 ms (CiSCI); 41 ± 3 ms) and motor evoked potentials (MEP) (32 ± 3 ms (CiSCI); 28 ± 2 ms) latencies were slightly increased in chronic incomplete spinal cord injury (iSCI) (CiSCI)
Applying up to 50% BWS to CiSCI during overground walking resulted in subtle changes of walking kinematics that are largely comparable to those observed in healthy controls

Summary

Introduction

Body weight support (BWS) is often provided to incomplete spinal cord injury (iSCI) patients during rehabilitation to enable gait training before full weight-bearing is recovered. Evidence for recovery induced by locomotor training has been extensively demonstrated in animal models [3, 4] Underlying this recovery is the neuroplasticity of spinal networks: Repetitive activation of task-specific input-output relationships that result in successful function favor remodeling, leading to Recent experiments in rats with iSCI have demonstrated that larger functional gains in basic and skilled. A case study [17] and more recent review [7] conclude that, in order to be maximally task-specific, neurological locomotor rehabilitation should be optimally conducted overground [5] While this is readily possible with patients who can support their own body weight, severely affected patients are dependent on BWS. Low transparency of the BWS system in medio-lateral direction can for instance result in a pendulum-like motion around the point of support during walking [21] influencing the regulation of body sway [22, 23]

Objectives

Methods

Results

Discussion

Conclusion