The goal of this study is to improve our understanding of speech production, and to translate this into medical devices called intracortical brain-computer interfaces (iBCIs) that will enable people who have lost the ability to speak fluently to communicate via a computer just by trying to speak.

The goal is to develop a new way to help people who lose the ability to speak due to neurological conditions including ALS or stroke, using an implanted medical device called a "brain-computer interface". The implanted medical device measures the person's brain activity as they try to talk and outputs their intended speech. By bypassing the injured parts of the nervous system this way, we can observe how individual brain cells are involved in speaking and working together as a network, to produce speech, and we can learn to decipher this activity to output what the person is trying to say.

Inclusion Criteria:

• Between 18 and 80 years of age
• 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 and geographically stable for at least 15 months after enrollment.

(There are additional inclusion criteria)

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)