EMG Triggered Closed-Loop Stimulation for Spinal Cord Injury Individuals
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|ClinicalTrials.gov Identifier: NCT03806023|
Recruitment Status : Terminated (Funding expired due to grant for new project (NCT03851302))
First Posted : January 16, 2019
Last Update Posted : October 5, 2020
Most individuals with spinal cord injury (SCI) have residual nerve circuits. The investigators aim to strengthen those circuits to improve motor recovery after injury. To do this, the investigators are attempting to pair electrical and magnetic stimulation with physical training targeted toward the connections between nerve circuits. Past studies by other groups have shown that synapse strength can be improved temporarily after a short period of paired stimulation between the brain (motor cortex) and the peripheral nerves serving target muscles - in other words, "Fire Together, Wire Together".
The brain's intention to move a muscle can be read by recording surface electrical activity over target muscles (electromyography or EMG). In animal models of SCI, scientists have successfully used target muscle EMG to trigger spinal cord electrical stimulation pulses while the animals perform physical exercises. Using the body's own signals to trigger nerve stimulation is called "closed-loop stimulation". This might be an optimal method to coordinate brain and nerve activity, especially with the clinical advantage of being possible to combine with physical exercise training. However, whether EMG-triggered closed loop stimulation has the same amount of effect when applied non-invasively in humans is still unknown.
This proposed study is a proof-of-principle to demonstrate the potential of non-invasive closed-loop stimulation in humans with incomplete cervical SCI. We will test different combinations of triggered and non-triggered electrical and magnetic stimulation, and record the short-term effects on nerve transmission and skilled function of hand muscles. This pilot study will be a foundation for future studies combining EMG-triggered stimulation with long-term physical exercise training.
|Condition or disease||Intervention/treatment||Phase|
|Spinal Cord Injuries||Device: hand movements (signals from thumb muscle) triggered PNS and TMS||Not Applicable|
In both animal models and humans with spinal cord injury (SCI), synaptic efficacy between corticospinal axons and spinal motor neurons has improved temporarily after a short period of paired stimulation between motor cortex and spinal or peripheral sites. In a demonstration of closed-loop stimulation in SCI rats, target muscle electromyography (EMG) signals were used to trigger spinal cord electrical stimulation while performing physical retraining. Results showed that EMG-triggered stimulation plus physical retraining led to greater motor recovery than non-triggered stimulation or physical training alone. However, these studies used invasive direct spinal cord stimulation in rodent models. Whether this approach can work non-invasively in humans remains unknown.
Twenty participants (10 able bodied and 10 SCI subjects) will be recruited. Each subject will undergo five different 20-minute interventions. Stimulation will be delivered at the motor cortex via transcranial magnetic stimulation (TMS), the median nerve, or both. Stimulation will occur either while the subject is passively at rest or triggered by reaching endogenous EMG threshold during a pinch task. Outcomes will be measured at baseline and every 20 minutes for one hour after the intervention.
The investigators hypothesize that for at least 20 minutes after stimulation, one session of EMG-triggered stimulation will significantly improve motor evoked potential amplitude, increase cortical silent period duration, and decrease time required to complete a pegboard task compared with one session of passively delivered stimulation. The investigators further hypothesize that EMG triggered median nerve stimulation alone will provide equal or greater benefits as EMG triggered TMS or EMG-triggered paired stimulation.
Hypothesis 1: One session of EMG-triggered stimulation will significantly improve motor evoked potential (MEP) amplitude, increase cortical silent period duration of APB, and decrease time required to complete a manual pegboard task compared with one session of passively delivered stimulation or one session of voluntary contraction alone for at least 20 minutes post-stimulation.
Hypothesis 2: EMG-triggered PNS alone will result in equal or greater effects than EMG triggered TMS or TMS+PNS paired stimulation. This would indicate that EMG triggered PNS might be used as a potential intervention to add during physical training, a setting in which TMS is difficult to apply.
|Study Type :||Interventional (Clinical Trial)|
|Actual Enrollment :||8 participants|
|Intervention Model:||Single Group Assignment|
|Masking:||None (Open Label)|
|Primary Purpose:||Basic Science|
|Official Title:||EMG Triggered Closed-Loop Stimulation for Spinal Cord Injury Individuals|
|Actual Study Start Date :||February 1, 2018|
|Actual Primary Completion Date :||February 28, 2020|
|Actual Study Completion Date :||February 28, 2020|
Experimental: All subjects
All subjects undergo same full protocol, including PNS and TMS at rest and active hand movements (signals from thumb muscle) triggered PNS and TMS.
Device: hand movements (signals from thumb muscle) triggered PNS and TMS
PNS, TMS or PNS+TMS will be delivered while the participant performs specific finger tasks at different degrees of effort.
This is an experiment designed to detect momentary changes in muscle function.
- Change in motor evoked potential (MEP) amplitude of the abductor pollicis brevis (APB) muscle response to single pulses of TMS [ Time Frame: Assessed pre, then 0, 20, 40, and 60 minutes post-intervention. ]
- Hand dexterity [ Time Frame: Assessed pre, then 0, 20, 40, and 60 minutes post-intervention. ]Timed performance on a grooved pegboard task.
- Grip strength [ Time Frame: Assessed pre, then 0, 20, 40, and 60 minutes post-intervention. ]Strength will be quantified using hand-held wireless dynamometry.
- Change in the duration of the 'cortical silent period' after TMS stimulation during APB contraction [ Time Frame: Assessed pre, then 0, 20, 40, and 60 minutes post-intervention. ]
- F-wave responses of the APB muscle [ Time Frame: Assessed pre, then 0, 20, 40, and 60 minutes post-intervention. ]
To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT03806023
|United States, New York|
|James J. Peters VA Medical Center|
|Bronx, New York, United States, 10468|
|Principal Investigator:||Noam Y Harel, MD, PhD||James J. Peters VA Medical Center|