Transcutaneous and Epidural Stimulation in SCI

The study seeks to improve the scientific understanding of how two electrical stimulation techniques, one which delivers electricity to the skin surface over the spine (transcutaneous electrical spinal stimulation \[TESS\]) and another which is implanted onto the dura mater of the spinal cord (epidural electrical stimulation \[EES\]), facilitate spinal circuitry to enable function after SCI.

The study will compare motor activity and clinical outcomes over the course of TESS and EES in combination with physical rehabilitation.

The primary outcome data collected will be used to characterize and compare spinal sensorimotor activity in muscles below the level of injury during TESS and EES-enabled motor tasks in persons with chronic motor complete paralysis of the lower extremities due to traumatic SCI. Furthermore, data collected will be used as a proof of concept that TESS can be used to determine recovery of function during EES-enabled motor tasks. Following exposure to each stimulation intervention, data collection will include changes to spasticity, body composition, metabolic variables, and spinal imaging to assess the effect of either TESS or EES stimulation.

Eligibility Criteria:
Inclusion Criteria:

* Spinal cord injury due to trauma located between the seventh cervical (C7) and tenth thoracic vertebrae (T10)
* American Spinal Injury Association grading scale of A or B (4 each of A and B) below the level of SCI
* Intact spinal reflexes below the level of SCI
* At least 1-year post-SCI
* At least 22 years of age
* Willing to use medically acceptable methods of contraception, if female and of child-bearing potential

Exclusion Criteria:

* Currently a prison inmate, or awaiting trial, related to criminal activity
* Pregnancy at the time of enrollment
* Dual energy x-ray absorptiometry (DEXA) t-score \<-3.5 at spine and femur head
* History of chronic and/or treatment resistant urinary tract infection
* Unhealed decubitus ulcer
* Unhealed skeletal fracture
* Untreated clinical diagnosis of depression
* Presence of joint contractures or an Ashworth spasticity score of 4
* Active anti-spasticity medication regimen within 3 months prior to study enrollment
* Presence of transcranial magnetic stimulation-evoked potentials in leg muscles
* Undergoing, or planning to undergo, diathermy treatment
* Active participation in another interventional clinical trial
* Presence of conditions or disorders which require MRI monitoring
* A history of coagulopathy or other significant cardiac or medical risk factors for surgery
* Current use of a ventilator
* Clinically diagnosed cardiopulmonary complications such as chronic obstructive pulmonary disease, cardiac failure, or heart arrhythmia that contraindicate changes in body position such as supine-to-sit-to-stand activities, prolonged standing, or stepping
* Mass \> 113 kg (250 pounds)
* History of frequent hypotension characterized by light headedness, or loss of consciousness
* History of frequent hypertension characterized by headache, or bradycardia
* History of frequent, severe, autonomic dysreflexia
* Any illness or condition which, based on the research team's assessment, will compromise with the patient's ability to comply with the protocol, patient safety, or the validity of the data collected during this study.