People with brainstem stroke, advanced amyotrophic lateral sclerosis (ALS, also known as Lou Gehrig's disease), or other disorders can become unable to move or speak despite being awake and alert. In this project, the investigators seek to further translate knowledge about interpreting brain signals related to movement, and to further develop an intracortical brain-computer interface (iBCI) that could restore rapid and intuitive use of communication apps on tablet computers by people with paralysis.

The goal of this project is to advance the methods by which people with tetraplegia can gain intuitive, reliable control of communication apps on industry-standard tablet computers through use of an intracortical brain-computer interface (iBCI).

Inclusion Criteria:

• Clinical diagnosis of spinal cord injury, brainstem stroke, muscular dystrophy, amyotrophic lateral sclerosis or other motor neuron disorders
• Complete or incomplete tetraplegia (quadriplegia)
• Must live within a three-hour drive of the Study site
• Prior enrollment in BrainGate2 clinical trial (NCT00912041)

Exclusion Criteria:

• Visual impairment such that extended viewing of a computer monitor would be difficult even with ordinary corrective lenses
• Chronic oral or intravenous steroids or immunosuppressive therapy
• Other serious disease or disorder that could seriously affect ability to participate in the study

(There are additional exclusion criteria)