NeuRx Diaphram Pacing System (DPS) Use in Amyotrophic Lateral Sclerosis (ALS)

Inclusion Criteria: * Age 21 or older * Familial or sporadic ALS diagnosed as possible, laboratory-supported probable, probable, or definite according to the World Federation of Neurology El Escorial criteria * Bilateral phrenic nerve function clinically acceptable as demonstrated by bilateral diaphragm movement with fluoroscopic sniff test or with phrenic nerve conduction studies * Chronic hypoventilation was documented by at least one of the following: * MIP (respiratory muscle strength) less than 60 cmH2O, or * Forced Vital Capacity (FVC) less than 50% predicted, or * PaCO2 greater than or equal to 45 mmHg, or * Nocturnal SaO2 (arterial oxygen saturation) less than or equal to 88% for at least five continuous minutes * Initiation of non-invasive ventilation at or before time of enrollment * Suitable surgical candidate to receive diaphragm pacing stimulation * Negative pregnancy test in female participants of childbearing potential (treatment group) * Informed consent from patient or designated representative Exclusion Criteria: * FVC less than 45% predicted within 10 days prior to surgery. * Participation in simultaneous therapeutic clinical trial which could affect the safety or benefit outcomes of this study.