Cervical Transcutaneous SCS for TBI

The goal of this study is to test the effects of non-invasive electrical stimulation of the spinal cord (called transcutaneous spinal cord stimulation, or tSCS) on arm and hand movement in people with motor impairments after a traumatic brain injury (TBI). Specifically, tSCS will be delivered using adhesive electrode pads placed on the skin over the upper back. The research team will measure how tSCS affects strength, movement control and muscle spasticity using different tests. Results of this study will help develop future treatments using an implanted (invasive) form of spinal cord stimulation to improve arm and hand function, helping people with TBI become more independent and improve their quality of life.

Inclusion Criteria: TRAUMATIC BRAIN INJURY (TBI) SUBJECTS: * Participants must have a suffered a traumatic brain injury resulting in impairments in arm and hand motor function at least one year prior to enrollment. * Participants must be between the ages of 21 and 70 years old. HEALTHY CONTROL SUBJECTS: * Participants must have full range of motion in their upper limbs; * Participants must be between the ages of 21 and 70 years old. Exclusion Criteria: TRAUMATIC BRAIN INJURY (TBI) SUBJECTS: * Participants with severe behavioral or cognitive impairments (e.g., aphasia, apraxia, visual neglect) that could preclude their ability to participate in the study. * Participants diagnosed with Paroxysmal Sympathetic Hyperactivity (PSH); * Participants with post-TBI heterotopic ossification or tendon contractures that restricts passive range of motion of upper limb joints; * Participants with uncontrolled epilepsy or untreated seizure disorders; * Participants with implanted electronic devices, such as pacemakers and spinal cord stimulators; * Participants taking benzodiazepine for spasticity; * Participants with serious disease or disorder (ex. neurological condition other than TBI, cancer, severe cardiac or respiratory disease, renal failure, etc.) that could affect their ability to participate in this study. * Female participants must not be pregnant or breast feeding. * Evaluation to sign consent form score \