Investigation on the Bidirectional Cortical Neuroprosthetic System

Eligibility Criteria

• * Participants with C4-C6 tetraplegia from any etiology except neurodegenerative disease (e.g. amyotrophic lateral sclerosis) or active cancer.
• * Complete or incomplete spinal cord injury classified by the American Spinal Injury Association (ASIA) as A or B or C if fewer than three muscle groups in the leg and foot (as identified in the ASIA Impairment Scale) can be contracted
• * Injury more than one year prior to enrollment
• * Participant has a life expectancy of greater than 5 years
• * Meeting surgical safety criteria, including surgical clearance by the participant's primary healthcare provider, study physicians, and any necessary consultants
• * Willingness and ability to provide informed consent
• * Screened by rehabilitation psychologist with a result showing that the participant has a stable psychosocial support system with caregiver capable of monitoring participant throughout the study
• * Ability and willingness to travel to up to fifty miles to study location up to three days per week for the duration of the study
• * Ability to understand and comply with study session instructions
• * Pain well controlled without narcotic medications
• * No other neurological, orthopedic conditions beyond the spinal cord injury
• * Participant consents to the study and still wishes to participate at the time of the study
• * Neurological conditions: Impaired receptive and/or expressive verbal communication skills
• * Presence of memory impairment on the Rey Auditory Verbal Learning Test
• * Intellectual impairment: score of 26 or less on the Mini-Mental State Examination or history of Intelligence Quotient \< 80
• * Chronic psychiatric illness, including psychosis and treatment-resistant major depression, as indicated by a diagnosis of Axis I or Axis II on the Symptom Checklist-90-Revised Test
• * Ventilator dependent
• * Implanted devices such as: pacemakers, cardiac defibrillators, spinal cord or vagal nerve stimulators, deep brain stimulators, cochlear implants or any other implantable device incompatible with MRI.
• * History of drug or alcohol dependence in past 24 months
• * Cerebral lesions affecting frontal and parietal lobes
• * Medical conditions contraindicating surgery of a chronically implanted device (e.g. osteomyelitis, diabetes, hepatitis, any autoimmune disease/disorder, epilepsy, skin disorders causing excessive skin sloughing or poor wound healing, blood or cardiac disorder requiring chronic anti-coagulation)
• * Other chronic, unstable medical conditions that could make control unsuitable (such as tremor or spasticity)
• * Presence of pre-surgical findings in anatomical, functional, and/or vascular neuroimaging that makes achieving implant locations within desired risk levels too challenging (to be decided by neurological and neurosurgical team)
• * Prior cranioplasty
• * Inability to undergo MRI or anticipated need for an MRI during the study period
• * Participants with active infections or unexplained fever
• * Participants with other morbid conditions making the implantation of the recording elements unsafe; not limited to: significant pulmonary, cardiovascular, or renal impairments making the surgical procedure unsafe
• * Pregnancy (confirmation through blood test)
• * Nursing an infant, planning to become pregnant, or not using adequate birth control
• * Corrected vision no worse than 20/30
• * HIV or AIDS infection
• * Existing scalp lesions or skin breakdown
• * Chronic oral or intravenous use of steroids or immunosuppressive therapy
• * Active cancer within the past year or requires chemotherapy
• * Uncontrolled autonomic dysreflexia within the past 3 months
• * An implanted ventricular shunt
• * Suicidal ideation within the past 12 months
• * Medications that affect neuroplasticity: neuroleptics, Benzodiazepines (BDZ), Tricyclic Antidepressants (TCA).