Plasticity Biomarkers, Interleukin 6, and Motor Performance Responses to Trans-auricular Vagus Nerve Stimulation Post-Stroke

OBJECTIVE: The aim of the study was to assess the influence of trans-auricular vagus nerve stimulation on serum Brain-Derived Neurotrophic Factors, interleukin 6, gross manual dexterity, and degree of spasticity after stroke. DESIGN: A randomized comparative study with 78 chronic stroke patients, randomly allocated into 2 groups with real or sham trans-auricular vagus nerve stimulation, Patients in control group received sham trans-auricular vagus nerve stimulation (30 mins), followed by a designed physical therapy program, while patients in experimental group underwent real trans-auricular vagus nerve stimulation (30 mins) followed by the same physical therapy program as control group. Treatment sessions were 3 times/week for 4 consecutive weeks. Brain-derived neurotrophic factor, interleukin 6, and 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 postintervention. RESULTS: There was a statistically significant improvement in all the primary outcomes (Brain-derived neurotrophic factor, interleukin 6, and Box and Blocks Test) in favor to the experimental group (experimental group) ( P < 0.05), However, no significant difference was observed in the secondary outcome (modified Ashworth scale) between both groups ( P ˃ 0.05). CONCLUSIONS: Noninvasive 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.