We are seeking individuals with ALS and breathing muscle weakness to participate in a research study enrolling under the direction of David Lacomis, MD. The purpose of the study is to determine whether the NeuRx® Diaphragm Pacing System™ (DPS) extends good quality of life and improves diaphragm function for people with ALS. While participating in this study, participants will undergo many breathing tests and will be asked to complete several questionnaires. The DPS device is surgically implanted during a brief hospital stay. Eligible participants will have a 2/3 chance of being randomized to receive DPS. All participants will undergo the same intensive testing of breathing muscle function, which may result in earlier detection of breathing symptoms. Participants must be at least 21 years of age. Participation involves six study visits and monthly phone calls for 18 months or more. If interested, please contact one of our coordinators at 412-864-2873 or 412-647-1706 or e-mail.