Safety and Feasibility of Paired Transcutaneous Auricular Vagus Nerve Stimulation (taVNS) With Upper Limb Rehabilitation in Incomplete Spinal Cord Injury

Inclusion Criteria:

* diagnosis of traumatic incomplete (AIS B-D) cervical spinal cord injury (C8 and above)
* at least 12 months post-traumatic SCI but less than 10 years post-SCI
* demonstrate some residual movement in the upper limb (e.g., able to perform pinch movement with thumb and index finger sufficient to grip small objects such as marble)

Exclusion Criteria:

* non-traumatic SCI
* recent ear trauma and skin lesions at the site of stimulation, such as sunburn, cuts, and open sores,
* facial or ear pain,
* allergic reaction to adhesives and electrodes,
* any current or past history of cardiovascular disorders,
* intracranial metal implants, pacemakers,
* concomitant clinically significant brain injury,
* receiving medication that may significantly interfere with the actions of VNS on neurotransmitter systems at study entry
* If there is a plan for alteration in upper-extremity therapy or medication for muscle tone during the course of the study;
* medical or mental instability;
* pregnancy or plans to become pregnant during the study period