Targeted transcutaneous cervical spinal cord stimulation promotes upper limb recovery in spinal cord and peripheral nerve injury

Long-term recovery of volitional control of the upper limb is a major unmet need in people with paralysis. Recently, it has been demonstrated that spinal cord stimulation, when paired with intense physical therapy, can restore volitional control of upper limb in spinal cord injury (SCI). Epidural stimulation of the spinal cord has traditionally been demonstrated to be highly effective in restoring movement, potentially due to the ability of targeted activation of specific motoneuron pools. However, transcutaneous spinal cord stimulation (tSCS) has recently shown equally promising results. In this study, we use a custom designed electrode patch and stimulator to enable targeted stimulation of specific spinal segments. We show that targeted transcutaneous stimulation of the cervical spinal cord can substantially and rapidly improve volitionally evoked muscle activity and force, even with minimal physical therapy, in two individuals with SCI. We also show, for the first time, the effectiveness of tSCS in restoring strength and dexterity in an individual with paralysis of the hand due to a peripheral injury.