Neuromodulation to Improve Respiratory Function in Cervical Spinal Cord Injury

Inclusion Criteria: 1. Male or female 18-75 years 2. At least 1 year from initial cervical spinal cord injury 3. Non-progressive Spinal Cord Injury (SCI) at C2 - C7 (non-conus injury) 4. Motor Complete ASIA Impairment Scale (A, B, or C) 5. Severe respiratory function compromise requiring dependency on invasive or noninvasive ventilation 6. Able to attend weekly testing sessions for up to 21 months. 7. Have intact chest/lung, upper and lower extremity anatomy. The neuromuscular connections between the spinal cord and its effector muscles (respiratory and extremity) are required to be intact 8. Have intact cognitive ability, able to follow commands/voice concerns, and give consent Exclusion Criteria: 1. History of severe autonomic dysreflexia 2. Phrenic nerve or diaphragm pacer 3. Phrenic nerve paralysis 4. Musculoskeletal dysfunction, unhealed fracture, pressure ulcer of grade 3 and above in the European Pressure Ulcer Advisory Panel Grading System, active infection 5. Clinically significant depression or ongoing drug abuse as documented in the medical record 6. Received lung surgery within one year prior to study enrollment or has active intrinsic lung disease (e.g. COPD, acute or chronic lung infection, moderate to severe asthma, emphysema, cystic fibrosis, etc.) 7. Cardiopulmonary disease that precludes training or rehabilitation 8. Other implanted stimulation devices 9. Pregnant 10. Severe cardiac disease (e.g. heart failure, atherosclerosis, arrhythmia, stroke, etc.) 11. Subjects involved in other clinical trials not associated with this trial 12. Botox injections in respiratory associated muscles within the last 3 months