The investigator is examining the use of one airway clearance medical device compared to the use of two airway clearance medical devices together in patients with amyotrophic lateral sclerosis (ALS). More specifically, the investigator wants to know how effective the use of either a mechanical High Frequency Chest Compression (HFCC) device is on its own or the use of both a mechanical High Frequency Chest Compression (HFCC) device and Cough Assist together to maintain a healthy airway and clear secretions. The first device is a passive form of mechanical High Frequency Chest Compression (HFCC), which was designed to help clear the airway of mucus and other secretions through mechanical knocking of the chest area. The second device, called a Cough Assist, aids patients to clear mucus and secretions that they would otherwise be unable to clear with coughing. This study will enroll up to 20 people in total at CSMC.