Weight Bearing Over-ground Stepping in an Exoskeleton with Non-invasive Spinal Cord Neuromodulation after Motor Complete Paraplegia

Abstract

We asked whether coordinated voluntary movement of the lower limbs could be regained in an individual having been completely paralyzed (>4 year) and completely absent of vision (>15 year) using two novel strategies—transcutaneous electrical spinal cord stimulation at selected sites over the spine as well as pharmacological neuromodulation by buspirone. We also asked whether these neuromodulatory strategies could facilitate stepping assisted by an exoskeleton (EKSO, EKSO Bionics, CA) that is designed so that the subject can voluntarily complement the work being performed by the exoskeleton. We found that spinal cord stimulation and drug enhanced the level of effort that the subject could generate while stepping in the exoskeleton. In addition, stimulation improved the coordination patterns of the lower limb muscles resulting in a more continuous, smooth stepping motion in the exoskeleton along with changes in autonomic functions including cardiovascular and thermoregulation. Based on these data from this case study it appears that there is considerable potential for positive synergistic effects after complete paralysis by combining the over-ground step training in an exoskeleton, combined with transcutaneous electrical spinal cord stimulation either without or with pharmacological modulation.

Reversing 21 years of chronic paralysis via non‐invasive spinal cord neuromodulation: a case study

“…However, this is almost an universal phenomenon following spinal cord injury, differing only in the degrees of abnormality of coactivations 18,19 . Prior research has shown that neuromodulation of the lumbosacral enlargement via tES increases the EMG activity in lower‐extremity muscles in SCI patients during treadmill 20 and robot‐assisted 21 locomotion. However, in the current study, tES exhibited little improvement in our patient’s bipedal walking.…”

The feasibility of using exoskeletal‐assisted walking with epidural stimulation: a case report study

“…A detailed description about different levels of swing assistance provided by EAW was published elsewhere . Therefore, it provides an opportunity to facilitate walking at a low‐metabolic cost for persons with SCI when walking with 100% swing assistance …”

“…Moreover, the appeal of noninvasive tools such as transcutaneous spinal stimulation (TSS) cannot be overlooked. Studies exploring the combinatory effects of EAW + TSS have demonstrated functional gains in a single participant . Future studies are warranted to confirm the beneficial effects of EAW + TSS on gaiting behaviors/outcomes; in addition, comparing both stimulation modalities may provide clinicians with multiple therapeutic tools for the rehabilitation of persons with SCI.…”

“…2 Therefore, it provides an opportunity to facilitate walking at a low-metabolic cost for persons with SCI when walking with 100% swing assistance. 2,18 Additionally, despite limited walking speeds (<0.4 mÁs À1 ), EAW is also less labor intensive for the rehabilitation teams 2 . High-intensity locomotor training has been linked to improving gait speed and muscle coordination.…”

“…Studies exploring the combinatory effects of EAW + TSS have demonstrated functional gains in a single participant. 18 Future studies are warranted to confirm the beneficial effects of EAW + TSS on gaiting behaviors/ outcomes; in addition, comparing both stimulation modalities may provide clinicians with multiple therapeutic tools for the rehabilitation of persons with SCI. Next, we did not have access to information regarding which variable (torque, displacement, or both) was modified when swing assistance level was reduced.…”