Transcutaneous Spinal Cord Stimulation for Rehabilitation of Upper Limbs in Early Spinal Cord Injury: Randomised Feasibility Study

Background Spinal Cord Injury affects more than 50,000 people in the UK, with an incidence of 2400 new cases every year. Muscular paralysis and sensory loss carry substantial physiological, psychological, financial, and social costs. Almost 60% of people affected by SCI sustain a high-level injury, that is, injury to spinal levels C2-T1, affecting arms and hands. Restoring hand and arm function is a top priority for people with tetraplegia, where even small improvements of motor function, combined with available assistive devices, may greatly improve independence and quality of life.

Transcutaneous spinal cord stimulation (tESCS) has emerged as a viable neuromodulation approach for facilitating the recovery of motor function in people with SCI. Studies that have applied tESCS at cervical segments combined with activity-based upper limb rehabilitation. Such active-assisted exercises such as gross and fine motor skill training, maximum voluntary contraction training, and unimanual and bimanual task performance have shown significant improvements in upper limb function.

It is believed that tESCS stimulation activates motor neuronal networks of the spinal cord, including the recruitment of afferent fibres in the posterior root, to elevate spinal network excitability. The underlying hypothesis is that after severe cervical SCI, nonfunctional sensory-motor networks within the cervical spinal cord can be transcutaneously neuromodulated to physiological states that enable and amplify voluntary control of the arm and hand.

A multicentre ONWARD Up-LIFT trial, which included 14 research sites, including QENSIU, has demonstrated functional improvements in people with incomplete chronic tetraplegia. As part of a UK Neuromodulation Network, we were awarded funding to deliver a substantial follow-up study, focusing on chronic complete tetraplegia. The results are showing some neurological recovery but modest functional improvement, indicating that some minimal level of preserved sensory or motor function is required in order to benefit from tESCS. For that reason, the investigators plan to recruit people with incomplete SCI in this study.

Rationale In the area of upper limb rehabilitation, the focus has been mainly on people with chronic SCI, likely due to the lack of alternative rehabilitation strategies and the difficulty in applying acute interventions in the clinical setting [3-8]. However, to date, there have been limited studies reporting the use of tESCS with people with subacute SCI. A randomised controlled trial with 22 complete or incomplete tetraplegic patients (3-12 months post injury, probably recruited from home) compared 8 sessions of tESCS with Armeo robot exercise to 8 sessions of Armeo alone. Both groups achieved comparable functional improvement but Armeo group had a higher change in scores. Our recent search of ClinTrials.gov (search criteria Spinal Cord Injuries, Upper extremity dysfunctions and electrical stimulation) has however, identified no current or future study which includes people with subacute SCI and randomisation.