Investigation on the Cortical Communication (CortiCom) System

The successful adoption of brain-computer interfaces (BCIs) as assistive technologies (ATs) for disabled populations depends on the ability to elicit rapid, intuitive, and reliable control signals. To date, it is not known which sources of neural information provide the most natural and efficient means of control. This study will directly assess the efficacy of two sources of neural control signals, speech and motor cortex, for BCI control of software and devices using investigators' Cortical Communication (CortiCom) system.

The CortiCom system consists of 510(k)-cleared components: platinum PMT subdural cortical electrode grids, a Blackrock Microsystems patient pedestal, and an external NeuroPort Neural Signal Processor. Up to two grids will be implanted in the brain, for a total channel count of up to 128 channels, for six months. In each participant, the grid(s) will be implanted over areas of cortex that encode speech and upper extremity movement.

Investigators' study will be the first to investigate the efficiency and intuitiveness of two contrasting neural control strategies for BCI: Motor imagery and speech. As the first study to chronically and simultaneously record from human speech and motor regions, this study seeks to achieve the following:

• demonstrate the ability to decode intended upper extremity movements using information decoded from primary motor cortex arm/hand area;
• demonstrate the ability to decode intended speech from articulatory speech cortex; and
• determine the most effective and intuitive user strategies (e.g. imagined speech or imagined movement) and optimal neural sources for brain-computer interactions,

The patient populations targeted in this study are amyotrophic lateral sclerosis (ALS), brainstem stroke, locked-in syndrome (LIS), and tetraplegia. Individuals within these populations may have normal cortical function and cognition while suffering from motor or combined speech and motor deficits.

Based on research by colleagues, as well as investigators' own experience working with participants affected by epilepsy implanted with high density electrocorticographic grids, investigators hypothesize that long-term recording of neural activity from the targeted cortical areas may provide a new communication channel for these clinical populations. The utilization of high-channel-count (up to 128 channel) ECoG grids, in combination with simultaneous coverage of speech and motor cortex, will enable investigations into the performance of speech-mediated and motor-mediated control efficacy as applied to a variety of end effectors, such as computers, tablets, headsets for virtual or augmented reality, smart lights, televisions, and assistive technologies. Additionally, eye-tracking may be utilized in combination with neural commands to improve target selection performance and ease.

Through this study, investigators will assess the performance of speech- and motor-mediated control using chronic, high-channel count ECoG grid neural implants in pursuit of a high-performing, clinically beneficial BCI assistive technology.

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