The functional benefits of temporary deafferentation (numbing)-induced cortical plasticity have been demonstrated in individuals with stroke, nerve damage, and pain syndromes. Of note, documented benefits have included improvements in motor function and touch perception in the weaker muscles. For example, Weiss et al demonstrated that temporary deafferentation to the forearm of the paretic limb in stroke for two hours during movement therapy improved motor performance of the hand by 10 to 48% after a single session. Another study established that bi-weekly sessions of temporary deafferentation for two weeks improved two-point discrimination and touch perception in individuals with ulnar/median nerve damage. More importantly, the authors found that improvements were retained for more than four weeks after the intervention ended. Collectively, this suggests that the release of tonic inhibition on weak muscle pathways, through temporary deafferentation, can lead to functional benefits that are retained long-term.~The Investigators' pilot findings indicate that temporary deafferentation shows similar benefits in the population of SCI. Specifically, it was observed that a single 30-minute session of temporary deafferentation to the stronger biceps can improve excitability to the weaker triceps and result in gains in hand dexterity and pinch strength in SCI.~The Investigators now seek to optimize the current study protocol before a large-scale clinical trial is conducted.
The investigators are conducting a research study to try to improve rehabilitation interventions for individuals with spinal cord injury (SCI). In this study, the aim is to determine if temporarily numbing non-paralyzed arm muscles with an over-the-counter numbing cream while exercising paralyzed muscles, can improve the strength, function, and sensation of paralyzed muscles after a spinal cord injury.