Trigeminal nerve stimulation (TNS) a form of nerve stimulation that is a safe and noninvasive way to activate the trigeminal nerve in the forehead. By stimulating the trigeminal nerve, we may be able to reduce sensitivity to various smells that are specifically sensed by the trigeminal nerve. This may help develop a new treatment for individuals that are over-sensitive to specific smells. The tools explored in this study are 1) Trigeminal Nerve Stimulation (TNS) and 2) Transcranial Direct Current Stimulation (tDCS). Both tools are non-invasive meaning that it does not involve any surgical procedures. TNS is a form of nerve stimulation that uses pulses of electricity delivered to stickers attached to the forehead. tDCS is a form of brain stimulation that uses sponges that are attached to your forehead which deliver a small, safe electrical current that activates your brain.

This study explores the use of a new form of neuromodulation known as transcutaneous auricular vagus nerve stimulation (taVNS) which stimulates the ear. This stimulation will be delivered concurrently with upper limb motor rehabilitation training (3 days/week for 4 weeks) in chronic stroke patients. Patients will undergo a series of baseline assessments (including a brain scan), a 4-week course of motor rehabilitation, and post-assessments (including a second brain scan).