tACS for Neuropathic Pain Management After SCI

Inclusion/exclusion criteria for SCI subjects Inclusion criteria: A patient who 1. has neuropathic pain after traumatic spinal cord injury or amputation or brain injury; 2. has chronic pain, \>3 months; 3. is between 18 to 75 years of age; 4. is stable on oral pain medications at least two weeks. Patients are allowed to continue their pain medications, i.e., no change in pain medications. NOTE: we plan to begin the study with the spinal cord injury (SCI) subject population as a cohort first, then expand to other subject populations Exclusion criteria: Patients will be excluded if they 1. are currently adjusting oral pain medications for their neuropathic pain; 2. have pain, but not neuropathic, e.g., from inflammation at the incision wound of the residual limb or neuroma; 3. have a pacemaker metal implants or supplemental oxygen; 4. have amputation in their arm(s); 5. fail to have a motor contraction in the arm muscles with TMS; 6. are not able to follow commands, or to give consent; 7. have asthma or other pulmonary disease; 8. are not medically stable; 9. have preexisting psychiatric disorders; 10. alcohol or drug abuse.