Non-invasive VNS in Stroke Recovery

In this study, (Aim 1) we will test whether our non-invasive trans-auricular vagus nerve stimulation (taVNS) during occupational therapy task performance has the potential for large scale application through superior clinical benefit compared to sham in a broad group of stroke survivors including hemorrhagic strokes. To determine the predictors of effective brain rewiring in the individual stroke patient, we will use an EEG and/or functional MRI (fMRI) connectivity biomarker independently of the success of the stimulation paradigm (Aim 2). We will test the hypothesis that better motor function will be associated with increased motor network connectivity pattern. The central objective of this application is to determine whether taVNS significantly improves motor recovery for both ischemic and hemorrhagic strokes through increased connectivity as measured by a biomarker of plasticity. We address our objective through the following aims: Aim 1: To determine the extent to which taVNS with concurrent occupational therapy (OT), causes significant, lasting motor gains in chronic stroke population Hypothesis A: More chronic stroke patients treated with taVNS+OT will show clinically meaningful improved hand motor function over Sham+OT immediately after treatment as measured by upper extremity Fugl-Meyer (uFM) test response rate. 60 patients at least 6 months after ischemic or hemorrhagic stroke with persistent arm weakness will be enrolled in a 6-week double masked, sham-controlled, balanced parallel group design phase 2 clinical trial. Hypothesis B: The sham group will achieve the same degree of motor function improvement in the open label cross-over phase as the original active taVNS group sustained clinical improvement after OT+VNS. Hypothesis C: The open label home extension taVNS+OT phase will produce additional motor function improvement and will be associated with improved patient and caregiver satisfaction. Aim 2: To determine the induced connectivity pattern of the brain resulting in the improved motor performance Hypothesis A: Chronic stroke patients with improved motor performance will demonstrate increased connectivity between motor cortical areas as measured by high-definition EEG and/or fMRI functional connectivity compared to the non-responders immediately after treatment. Hypothesis B: Network activation with taVNS is dependent on timing compared to movement and stimulation intensity. We will perform fMRI and /or high-definition EEG to evaluate network activity during taVNS at different intensity and phase of the movement. This study evaluates the feasibility, efficacy and underlying plasticity changes of adjuvant noninvasive VNS to enhance motor recovery following ischemic and hemorrhagic strokes.