Twelve adults will participate in a single- subject A1-B-A2 study involving 4 visits to Duke over 24 weeks. The 6 week delayed start period (A1) will establish baseline status prior to initiation of RMT (B) and the follow-up period (A2) will determine detraining effects over 6 weeks of RMT withdrawal. Participants will complete four 3-week cycles of progressive RMT during the B phase. The investigators will measure MIP and MEP weekly. To reduce participant burden and enhance our ability to obtain repeated measures, the investigators will obtain 21 of 25 measurements of MIP and MEP during web-based telehealth visits.
Participants will complete a full assessment during the first study visit (M1) and receive training/instruction for obtaining MIP and MEP measurements at home with a portable, battery-powered digital pressure gauge manometer (MicroRPM Pressure Meter; Micro Direct). They will return to Duke for the pretest visit (M7), at which time a full assessment will be completed and RMT will commence. During the B phase, participants will complete 12-weeks of moderate intensity RMT, divided into four 3-week cycles, and participate in weekly web-based RMT therapy visits (M8-M18). Post-test assessment (M19) will occur immediately following completion of the 12-week RMT regimen. The investigators will measure MIP and MEP during RMT withdrawal via web-based telehealth visits (M20-24). Following the fourth and final on-site full assessment visit (M25), participants will return all equipment and will be offered the opportunity to initiate a clinical RMT regimen and receive follow-up care by Speech Pathology during future ALS Clinic visits.
Participants will be stratified into 2 groups based on baseline inspiratory muscle strength as determined by maximum inspiratory pressure (MIP): six participants with minimal to no respiratory weakness (i.e., MIP 70% predicted) and six participants with mild to moderate inspiratory weakness (i.e., MIP 40-70% predicted).
The primary outcomes are MIP and MEP. Secondary outcomes include peak cough flow (PCF) and sniff nasal inspiratory pressure (SNIP). Exploratory outcomes include the Amyotrophic Lateral Sclerosis Functional Rating Scale (ALSFRS), Eating Assessment Tool - 10 Item (EAT-10), 36-Item Short Form Survey (SF36), World Health Organization Quality of Life-BREF (WHOQOL-BREF), and Communicative Effectiveness Survey-Revised (CES-R). Clinical spirometry data will be extracted from the participant's electronic medical record if available from a coinciding ALS Clinic visit that occurs +/- 5 days from the assessment visit.
