Cardiovascular safety of transcutaneous spinal cord stimulation in cervical spinal cord injury.

This study evaluated whether cervical transcutaneous spinal cord stimulation (tSCS) in conjunction with rehabilitation on upper extremity function alters blood pressure regulation in individuals with cervical spinal cord injury. This study is a secondary analysis of the Up-LIFT trial, a prospective single-arm multicenter trial designed to evaluate the safety and efficacy of tSCS in conjunction with rehabilitation (tSCS ​+ ​rehab) on upper extremity function in individuals with chronic cervical spinal cord injury. Utilizing this large data set obtained from 60 individuals across 14 international sites, we compared blood pressure and heart rate measurements obtained before, during and after each training session during both the wash-in Rehab alone period and the tSCS ​+ ​rehab period of the trial. Blood pressure and heart rate were recorded during each session throughout the protocol in all participants. Sessions of tSCS ​+ ​rehab did not cause significant changes in blood pressure or heart rate compared to Rehab alone (p ​> ​0.05). Further, blood pressure medications did not have an effect on these cardiovascular responses to tSCS (p ​> ​0.05). This study supports the safety profile of cervical tSCS paired with rehabilitation in individuals with cervical spinal cord injury. The lack of adverse effects on blood pressure and heart rate during the intervention, together with the previously reported clinically meaningful improvements in upper extremity strength and function strongly supports the utility of tSCS in this patient population. Further work is required to elucidate potential long-term effects of targeted tSCS on cardiovascular function in people with spinal cord injury.