Plasticity Biomarkers, Interleukin-6 and Motor Performance Responses to Trans-auricular Vagus Nerve Stimulation Post-Stroke: A Randomized Controlled Trial

OBJECTIVES: To assess the influence of trans-auricular Vagus nerve stimulation (TaVNS) on serum Brain-Derived Neurotrophic Factors (BDNF), Interleukin-6 (IL-6), gross manual dexterity and degree of spasticity post stroke. DESIGN: A randomized comparative study with 78 chronic stroke patients, randomly allocated into 2 groups with real or sham TaVNS, Patients in control group (GA) received sham TaVNS (30 mins) followed by a designed physical therapy (PT) program, while patients in experimental group (GB) underwent real TaVNS (30 mins) followed by the same PT program as GA. Treatment sessions were 3 times/week for 4 consecutive weeks. BDNF, IL-6, gross manual dexterity were the primary outcomes, while degree of spasticity was a secondary outcome. Primary and secondary outcomes were assessed at baseline and immediately post-intervention. RESULTS: There was a statistically significant improvement in all the primary outcomes (BDNR, IL-6 & BBT) in favor to the experimental group (GB) (P < 0.05), However no significant difference was observed in the secondary outcome (MAS) between both groups (P ˃0.05). CONCLUSIONS: Non-invasive VNS as an adjunct to conventional rehabilitation enhances neuroplasticity and improves upper limb motor ability post ischemic stroke as well as it could reduce the stroke-induced inflammatory process which may affect the disease prognosis.