Investigation on the Cortical Communication (CortiCom) System

Inclusion Criteria: * Clinical diagnosis of tetraplegia (quadriplegia), brainstem stroke , amyotrophic lateral sclerosis (ALS) or Locked-in Syndrome (LIS) * Tetraplegia diagnosis, ALS diagnosis, stroke, or LIS etiology onset occurred at least one year prior to enrollment * Complete or incomplete tetraplegia (quadriplegia), tetraparesis (quadriparesis), or severe ataxia. In addition, these motor impairments may be combined with severe motor-related speech impairment (dysarthria or anarthria), as in LIS. * 22-70 years * Meeting surgical safety criteria, including surgical clearance by the participant's primary healthcare provider, study physicians, and any necessary consultants * Ability to communicate reliably, such as through eye movement * 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 up to 100 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 * Participant consents to the study and still wishes to participate at the time of the study Exclusion Criteria: * Performance on formal neuropsychological testing that indicates significant psychiatric conditions or cognitive impairments that would interfere with obtaining informed consent or fully participating in study activities. * Suicide attempt or persistent suicidal ideation within the past 12 months. * Implanted devices that are incompatible with MRI, which may include pacemakers, cardiac defibrillators, spinal cord or vagal nerve stimulators, deep brain stimulators, and cochlear implants. * History of substance abuse, narcotic dependence, or alcohol dependence in past 24 months * 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 interfere with subject participation. * 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, metabolic, 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 poorer than 20/100 * 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 * Hydrocephalus with or without an implanted ventricular shunt * Participants in whom it is medically contraindicated to stop anti-coagulant medications during surgery