Stanford NPTL is part of the BrainGate Clinical Trial, "BrainGate2: Feasibility study of an intracortical neural interface system for people with tetraplegia." (Sponsor and PI: Leigh Hochberg, MD, PhD; Clinical Trials.gov: NCT00912041). The purpose of the first phase of the pilot clinical study of the BrainGate2 Neural Interface System is to obtain preliminary device safety information and to demonstrate the feasibility of people with tetraplegia using the System to control a computer cursor and other assistive devices with their thoughts. Another goal of the study is to determine the participants’ ability to operate communication software, such as e-mail, simply by imagining the movement of their own hand. The study is invasive and requires surgery. Individuals with limited or no ability to use both hands due to cervical spinal cord injury, brainstem stroke, muscular dystrophy, or amyotrophic lateral sclerosis (ALS) or other motor neuron diseases are being recruited into a clinical study at Massachusetts General Hospital (MGH), Stanford University and Case Western Reserve University. Clinical trial participants must live within a three-hour drive of Boston, MA, Palo Alto, CA or Cleveland, OH. Clinical trial sites at other locations may be opened in the future. The study requires a commitment of 13 months.