VNS-supplemented Motor Retraining After Stroke

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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To establish a link between the physiological mechanisms driving enhanced motor control in response to VNS, subjects will undergo progressive training on a visuomotor task that requires fine gradation of voluntary motor output to control a moving object through target boundaries. In separate groups, VNS or sham stimulation will be paired with movement when a minimal time-on-target (ToT) is achieved.

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, Acute

Intervention / Treatment
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* Other: Training
* Other: Vagus Nerve Stimulation
* 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: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Vagus nerve stimulation (VNS)<br>Stroke and control subjects will undergo 3 testing sessions and 8 training sessions in these experiments. Subjects will hold a force transducer between the index finger and thumb to control the path of an object through targets displayed on a computer monitor. VNS will be delivered when a minimum level of accuracy has been achieved. | Other: Training<br>* Controlling movement of an object on computer screen by adjusting muscle activity.<br>Other: Vagus Nerve Stimulation<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: Sham stimulation<br>Stroke and control subjects will undergo 3 testing sessions and 8 training sessions in these experiments. Subjects will hold a force transducer between the index finger and thumb to control the path of an object through targets displayed on a computer monitor. Sham stimulation will be delivered when a minimum level of accuracy has been achieved. | Other: Training<br>* Controlling movement of an object on computer screen by adjusting muscle activity.<br>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 time-on-target score. | The score reflects the total time the object overlaps any part of targets, expressed as a percentage (0-100) of the total possible time. Thus, a score of 0 is the worst possible score, whereas, 100 is the best possible score. The primary endpoint is the change from baseline (ie, before training) in the time-on-target score. | 3 weeks |