VNS-induced Corticospinal Plasticity

Study Overview
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Brief Summary
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The goal of this study is to learn more about the connections between the brain, spinal cord, and muscles and how these connections can be strengthened after neurological injury.

Detailed Description
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Non-invasive stimulation techniques can be used to appropriately time converging inputs to induce changes in cortical output circuits of human primary motor cortex, a neuromodulatory protocol known as paired-associative stimulation (PAS). Experiments seek to examine interactions between cortical PAS and non-invasive vagus nerve stimulation (VNS) to understand the extent to which VNS amplifies cortical plasticity in humans.

Official Title
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Mechanisms of Non-invasive Vagus Nerve Stimulation Underlying Enhanced Motor Control in Humans

Conditions
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Stroke

Intervention / Treatment
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* Other: Paired-Associative Stimulation (PAS)
* Other: Vagus Nerve Stimulation (VNS)
* Other: Sham Stimulation


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: INDIVIDUALS WHO HAVE HAD A STROKE: Diagnosis of first ever stroke At least 6 months after stroke onset Motor-evoked potentials in hand/arm muscles Subjects must show an understanding of the study goals and have the ability to follow simple directions as judged by the investigators. ALL INDIVIDUALS: Between the ages of 18 and 75 years old Exclusion Criteria: INDIVIDUALS WHO HAVE HAD A STROKE: Hemispatial neglect, aphasia, or cognitive impairment that would impact testing and would interfere with the ability to follow simple instructions, as judged by the investigators ALL INDIVIDUALS: Neurological disorder(s) influencing movement (besides stroke) History of seizure or epilepsy Metallic brain implants Bodily implants such as cardioverter defibrillators, insulin pumps, ventriculoperitoneal shunts, cochlear implants, or pacemakers Pregnant or expecting to become pregnant Difficulty maintaining alertness and/or remaining still Silicone or plastic allergy History of vestibular disorders (eg, Vertigo, Meniere's Disease, etc.)

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 75 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Other
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: PAS+VNS<br>Paired-associative stimulation (PAS) targeting primary motor cortex will be administered with VNS in individuals with hemiparesis secondary to stroke and neurologically-intact, age-matched controls. | Other: Paired-Associative Stimulation (PAS)<br>* Simultaneous activation of connections in motor cortex via stimulation to the nerves and brain.<br>* Other names: PAS;Other: Vagus Nerve Stimulation (VNS)<br>* Recruits the auricular branch of the vagus nerve which activates brain structures that release chemicals mediating cortical plasticity.<br>* Other names: VNS;|
| Sham Comparator: PAS+Sham<br>Paired-associative stimulation (PAS) targeting primary motor cortex will be administered with sham stimulation in individuals with hemiparesis secondary to stroke and neurologically-intact, age-matched controls. | Other: Paired-Associative Stimulation (PAS)<br>* Simultaneous activation of connections in motor cortex via stimulation to the nerves and brain.<br>* Other names: PAS;Other: Sham Stimulation<br>* Sub-threshold stimulation that does not activate neural structures.<br>* Other names: Sham;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in size of evoked potential | The primary endpoint is the change from baseline (ie, before PAS) in the size of evoked potentials. Differences in the change between conditions (ie, PAS+VNS vs PAS+Sham) will address whether VNS drives cortical plasticity. | 1 week | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Neuromodulation, Paresis, Neurorehabilitation