Effects of Transcutaneous Vagal Nerve Stimulation on Post-Surgical Return to Consciousness, Delirium, and Depression

Inclusion Criteria: 1. Aged \> 18 years of age 2. Patients undergoing lumbar surgery for degenerative disc disease or spinal stenosis involving two or more levels 3. Montreal Cognitive Assessment (MoCA) score ≥ 18 - accept mild 4. Ability to use a keyboard 5. Able to understand and communicate in English 6. Be able to consent independently 7. Women of child-bearing age must be comfortable confirming a negative pregnancy prior to participating in the study. 8. Must not be involved in any other research intervention study testing neurobehavioral functioning Exclusion Criteria: 1. Age \< 18 years of age 2. History of vagotomy (cutting the vagus nerve) 3. History of bradycardia, heart block, prolonged QT syndrome, brugada syndrome, heart failure with ejection fraction less than 35% and/or New York Heart Association symptoms 4. MoCA \< 18 5. History of seizure disorder or intracranial hemorrhage 6. Patients with carotid stenosis 7. Patients with aneurysms 8. Other neurological diagnoses or a diagnosis of severe psychiatric disorder (e.g., psychosis) or a reported childhood learning disability 9. Pregnancy, breastfeeding 10. Active addiction history 11. ECG adhesive allergy 12. Severe aphasia, preventing subject from understanding the protocol and giving written consent 13. Patients will be excluded postoperatively if there is neck swelling at the proposed site of left tcVNS.