Investigating the Acute Effects of Transcutaneous Electrical Stimulation Parameters on Neural Circuits, Motoneuron Behavior and Motor Performance in Individuals With Cervical Spinal Cord Injury
Overview
- Phase
- Not Applicable
- Intervention
- Not specified
- Conditions
- Spinal Cord Injuries
- Sponsor
- University of Louisville
- Locations
- 1
- Primary Endpoint
- Force control
- Status
- Withdrawn
- Last Updated
- 2 years ago
Overview
Brief Summary
The purpose of this study is to examine how delivery of subthreshold electrical stimulation of the spinal cord alters the excitability of neural pathways and consequently movement performance in healthy and spinal cord injured individuals. Specifically, we assess how stimulation parameters such as electrode configurations and stimulation frequency affect spinal excitability, corticospinal excitability, intracortical excitability, motor unit properties and force production. This study is not an intervention study, but a mechanistic study trying to shed light on how this novel neuromodulatory technique acutely affects the central nervous system.
Investigators
Eligibility Criteria
Inclusion Criteria
- •cervical level injury (C5 to C7)
- •at least 1 year post-injury
Exclusion Criteria
- •individuals with damage to the nervous system other than to the spinal cord
- •pregnant women (effects of stimulation on the fetus are unknown).
- •Transcranial magnetic stimulation-specific exclusion criteria:
- •participants with active or inactive implants including cardiac pacemakers, implantable defibrillators, ocular implants, deep brain stimulators, vagus nerve stimulator, and implanted medication pumps
- •participants with conductive, ferromagnetic or other magnetic-sensitive metals implanted in their head
- •participants with a history of seizures or epilepsy
- •participants taking any medication which may reduce seizure threshold
Outcomes
Primary Outcomes
Force control
Time Frame: Assessment up to 4 hours each visit; up to 4 visits per individual (32 hours)
Force control during a variety of motor tasks is assessed during delivery of tcES. Comparisons are made between no stimulation and stimulation at different frequencies, or with different electrode configurations within each session. This assessment is repeated for different muscles on different days.
Motor evoked potentials recruitment curves
Time Frame: Assessment up to 4 hours each visit; up to 4 visits per individual (32 hours)
Motor evoked potentials are obtained to assess changes in the input/output properties of the corticospinal tract during delivery of tcES. Comparisons are made between no stimulation and stimulation at different frequencies, or with different electrode configurations. This assessment is repeated for different muscles on different days.
Intracortical excitability
Time Frame: Assessment up to 4 hours each visit; up to 4 visits per individual (32 hours)
Paired stimulation of the motor cortex is used to assess short interval intracortical inhibition intracortical facilitation during delivery of tcES. Comparisons are made between no stimulation and stimulation at different frequencies, or with different electrode configurations. This assessment is repeated for different muscles on different days.
Intramuscular coherence
Time Frame: Assessment up to 4 hours each visit; up to 4 visits per individual (32 hours)
High-density surface electromyography is used to decompose motor units and assess changes in intramuscular coherence during performance of a motor task in the presence of tcES. Comparisons are made between no stimulation and stimulation at different frequencies, or with different electrode configurations. This assessment is repeated for different muscles on different days.