Transcutaneous Vagus Nerve Stimulation (tVNS) and Robotic Training to Improve Arm Function After Stroke

Promising new animal research suggests that vagus nerve stimulation paired with motor intervention induces movement-specific plasticity in the motor cortex and improves limb function after stroke. These results were recently extended to the first clinical trial, in which patients with stroke demonstrated significant improvements in upper limb function following rehabilitation paired with implanted VNS. Currently, vagus nerve stimulation is being used clinically to treat a number of human diseases including migraine headaches, epilepsy, and depression, and these investigations are expanding to deliver stimulation via a transcutaneous route to potentially improve intervention efficacy and decrease side effects. This pilot study will combine non-invasive transcutaneous stimulation of the vagus nerve with upper limb robotic therapy to investigate the potential of tVNS to augment improvements gained with robotic therapy in patients with chronic hemiparesis after stroke.

Inclusion criteria

• Individuals between 18 and 85 years of age
• First single focal unilateral supratentorial ischemic stroke with diagnosis verified by brain imaging (MRI or CT scans) that occurred at least 6 months prior
• Cognitive function sufficient to understand the experiments and follow instructions (per interview with Speech Pathologist or PI)
• Fugl-Meyer assessment 12 to 44 out of 66 (neither hemiplegic nor fully recovered motor function in the muscles of the shoulder, elbow, and wrist).

Exclusion criteria

• Botox treatment within 3 months of enrollment
• Fixed contraction deformity in the affected limb
• Complete and total flaccid paralysis of all shoulder and elbow motor performance
• Prior injury to the vagus nerve
• Severe dysphagia
• Introduction of any new rehabilitation interventions during study
• Individuals with scar tissue, broken skin, or irremovable metal piercings that may interfere with the stimulation or the stimulation device
• Highly conductive metal in any part of the body, including metal injury to the eye; this will be reviewed on a case by case basis for PI to make a determination
• Pregnant or plan on becoming pregnant or breastfeeding during the study period
• Significant arrhythmias, including but not limited to, atrial fibrillation, atrial flutter, sick sinus syndrome, and A-V blocks (enrollment to be determined by PI review)
• Presence of an electrically, magnetically or mechanically activated implant (including cardiac pacemaker), an intracerebral vascular clip, or any other electrically sensitive support system; Loop recorders will be reviewed on a case by case basis by PI and the treating Cardiologist to make a determination