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.
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.
Study Type
INTERVENTIONAL
Allocation
NON_RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
Ebanel 5% Lidocaine Topical Numbing Cream Maximum Strength 1.35 Oz, Numb520 Pain Relief Cream Anesthetic Cream Infused with Aloe Vera, Vitamin E, Lecithin, Allantoin, Secured with Child Resistant Cap
reaching tasks, hand exercises (e.g., putty, grip exerciser, resistance bands, etc).
University of Texas Rio Grande Valley
Harlingen, Texas, United States
Electromyography (EMG)
The investigators will use an electrical stimulator to send an electrical signal to a target muscle to initiate contraction, and an Electromyography (EMG) will be used to record the changes in target muscle response from baseline, pre-test, and post-test. An electronic nerve stimulator will output a pulse ranging from 0 mV to 2 mV for an appropriate maximum muscle contraction to occur, and an Electromyography (EMG in root mean square) will capture the muscle's contraction via surface electrodes. A greater number of Root Mean Square (RMS) millivoltage registered on the EMG signifies a higher response from the muscle, additionally, any plateau of the RMS while administering higher mV from the Stimulator will signify a maximum contraction of the muscle.
Time frame: Throughout Study Duration, an average of four weeks
Transcranial Magnetic Stimulation (TMS)
Using Transcranial Magnetic Stimulation (TMS) to promote Motor Evoked Potentials (MEP), the Investigators will monitor changes in cortical excitability of the target muscle's motor hotspot by measuring the muscle excitability with Electromyography (EMG; in millivolts) from Baseline, Pre-test, and at Post-test. The motor hotspot of the weak muscle will be defined as the site that evokes MEPs ≥50 mV at the lowest intensity (% device output), or the resting motor threshold (RMT). A decrease of the TMS's percentage output to promote MEPs of the weak muscle signifies a decrease in the cortical excitability, as measured by Active Motor Thresholds (AMT) and Active Motor Evoked Potentials (AMEP).
Time frame: Throughout Study Duration, an average of four weeks
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