funding not continued

This study will evaluate the safety and effectiveness of Respiratory-gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) for improving motor recovery after stroke. Subacute stroke patients will receive RAVANS or sham stimulation concurrent with arm motor training during 10 intervention sessions occurring daily for 30 minutes over 2 weeks. The safety and improvements in arm motor function after the intervention will be compared in patients receiving RAVANS to those receiving sham stimulation.

This study will evaluate the safety, feasibility and effectiveness of Respiratory-gated Auricular Vagal Afferent Nerve Stimulation (RAVANS) for improving motor recovery after stroke. Subacute stroke patients will be randomized to RAVANS or sham stimulation groups. Patients will receive RAVANS or sham stimulation concurrent with arm motor training during 10 sessions occurring daily for 30 minutes over 2 weeks. Safety will be compared in patients receiving RAVANS to those receiving sham stimulation. Feasibility will be evaluated by recruitment into the study and retention of enrolled patients. Changes in arm motor function will be compared between RAVANS and sham stimulation groups from baseline to immediately after the intervention period and to function at 3-months after stroke.

Inclusion Criteria:

• Supratentorial ischemic or hemorrhagic stroke incurred 4-30 days prior;
• Contralesional UL motor impairment defined by NIHSS item 5 score 1 or 2 (scale 0-4);
• Age ≥ 18;
• Able to provide written informed consent.

Exclusion Criteria:

• Implanted electronic device (e.g., pacemaker, neurostimulator);
• Pregnancy;
• Major psychiatric or medical condition that could interfere with study participation;
• Medical condition affecting left ear that could interfere with delivering RAVANS (e.g., wound, infection, malignancy, hypoesthesia);
• Significant pre-existing disability of stroke-affected UL in activities of daily living due to prior stroke or other medical cause defined by Stroke Impact Scale item 7 (SIS-hand) mean score < 4 (scale: 0-5);
• History of seizure during year before stroke or > 1 post-stroke seizure;
• Significant cognitive or language impairment that would interfere with informed consent or study participation;
• Severe dysphagia;
• Bradycardia defined as resting heart rate < 50 bpm;
• Nonsustained ventricular tachycardia;
• Cardiac conduction disorder (i.e., bundle branch block, heart block, long Q-T syndrome);
• History of asystole;
• History of recurrent vaso-vagal syncope;
• Hypotension defined as blood pressure < 90/60 mmHg.