Transcutaneous Auricular Vagus Nerve Stimulation to Improve Upper Extremity Recovery After Traumatic Brain Injury

Upper extremity weakness, impaired coordination, reduced dexterity, and limited arm and hand use may continue after TBI. Repetitive, task-specific rehabilitation may improve function, but recovery can remain incomplete. taVNS is a non-invasive form of electrical stimulation delivered to part of the outer ear. The stimulation is intended to activate nerve pathways involved in learning and brain plasticity while you practice upper extremity tasks. This pilot study will evaluate safety, tolerability, feasibility, and preliminary effects on upper extremity function and cognition. Up to 40 people will take part at Craig Hospital.

Inclusion Criteria: * Age 18 years or older. * History of TBI requiring inpatient rehabilitation, with resulting upper extremity impairment in at least one limb * Passive range of motion within functional limits at the wrists, shoulders, and elbows. * Able to attend on-site training at Craig Hospital three times per week for four weeks. * No complicating physical or cognitive condition, as determined by the physician or study investigator, that would preclude safe use of taVNS. * If taking prescribed antispasticity medication, dose stable for at least four weeks before study procedures. * Able to provide informed consent. Exclusion Criteria: * Recent fracture or contracture that could interfere with the intervention. * Botulinum toxin injections to the upper extremity or hand within the previous three months. * Pregnant, planning pregnancy, or breastfeeding. * Concurrent participation in another drug or device trial that may interfere with this study. * Implanted pacemaker, spinal cord stimulator, ventriculoperitoneal shunt, deep brain stimulator, or intrathecal pump. * Any condition or circumstance that, in the investigator's judgment, makes participation unsafe or inappropriate.