An interventional study of Respiratory Muscle Training in ALS, sponsored by Duke University. Completed at 1 site in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-01-29.
Sponsored by Duke University · Not applicable, Interventional, and Supportive care
Twelve adults with ALS will participate in a study involving four 3-week cycles of progressive respiratory muscle training (RMT). The investigators will measure maximum inspiratory pressure (MIP) and maximum expiratory pressure (MEP) weekly. The investigators will obtain the majority of measurements of MIP and MEP during web-based telehealth 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).
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.
Duke University is the lead sponsor of 2,025 studies on the registry; 275 are open to participants now.
Of its 194 completed or terminated interventional studies of FDA-regulated products, 159 (82%) have results posted.
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Exclusion Criteria:
MIP ≥ 70% predicted Complete home-based RMT program and participate in weekly web-based RMT therapy sessions.
Device: Respiratory Muscle Training
MIP 40-70% predicted Complete home-based RMT program and participate in weekly web-based RMT therapy sessions.
Device: Respiratory Muscle Training
Two commercially available pressure-threshold RMT devices that utilize a spring-loaded flange to provide resistance against inspiration and expiration independent of respiratory flow rate will be used to provide the necessary range of resistance. Each participant will use two RMT devices, one for IMT and one for EMT.
Also known as: EMST 150, Threshold IMT
Number of Participants With Safe, Well-tolerated Moderate Intensity Respiratory Muscle Training (RMT) as Measured by Rating of Perceived Exertion (RPE)
Safe, well-tolerated moderate intensity Respiratory Muscle Training (RMT) is in part defined as an RPE between 4-5 and \<6. The RPE is a way of measuring physical activity intensity level. Perceived exertion is how hard the participant feels like their body is working. 0 = rest, 1 = very easy, 2 = easy, 3 = moderate, 4 = somewhat hard, 5 = hard, 6 = harder, 7 = very hard, 8/9 = extremely hard, 10 = maximal.
Time frame: 12 weeks
Number of Participants With Safe, Well-tolerated Moderate Intensity Respiratory Muscle Training (RMT) as Measured by Pain Score
Safe, well-tolerated moderate intensity Respiratory Muscle Training (RMT) is in part defined as a pain rating of \<4 on a standard 0-10 scale, where 0 = no pain and 10 = the worst pain possible.
Time frame: 12 weeks
Number of Participants Able to Complete Respiratory Muscle Training (RMT)
Feasibility will be determined by the number of participants able to complete the Respiratory Muscle Training
Time frame: 12 weeks
Magnitude of Change in Maximum Inspiratory Pressure From Pre-test to Post-test as Determined by Cohen's Measure of Effect Size
Magnitude of change for our primary outcome measures will be determined using Cohen's measure of effect size (d) as defined by the first equation for single-subject d provided by Busk and Serlin (1992). Simply stated, d is obtained by subtracting the mean of the first assessment from the mean of the second assessment, divided by the standard deviation of the first assessment. Effect size calculations will be determined to compare results from pre-test (M7) to post-test (M18). The investigators will use conservative interpretation guidelines for effect size calculations in which d \< 0.6 is negligible, d ≥ 0.6 modest, d ≥ 1.0 large, and d ≥ 2.0 very large.
Time frame: from pre-test (week 7) to post-test (week 18)
Magnitude of Change in Maximum Expiratory Pressure From Baseline to Withdrawal as Determined by Cohen's Measure of Effect Size
Magnitude of change for our primary outcome measures will be determined using Cohen's measure of effect size (d) as defined by the first equation for single-subject d provided by Busk and Serlin (1992). Simply stated, d is obtained by subtracting the mean of the first assessment from the mean of the second assessment, divided by the standard deviation of the first assessment. Effect size calculations will be determined to compare results from baseline (M0-M5) to withdrawal (M19-M24). The investigators will use conservative interpretation guidelines for effect size calculations in which d \< 0.6 is negligible, d ≥ 0.6 modest, d ≥ 1.0 large, and d ≥ 2.0 very large.
Time frame: from baseline to withdrawal (up to week 24)
Change in Peak Cough Flow in L/Min
Effective peak cough flow in healthy subjects exceeds values of 360 to 400 L/min. PCF is measured at baseline, visit 7, visit 18 and visit 24. The overall change from baseline to visit 24 will be measured.
Time frame: Baseline, 7 weeks, 18 weeks, 24 weeks
Change in Sniff Nasal Inspiratory Pressure
The sniff nasal inspiratory pressure (SNIP) consists in the measurement of pressure through an occluded nostril during sniffs performed through the contralateral nostril. SNIP is measured through a plug occluding one nostril during sniffs through the contralateral nostril. A plateau in pressure is reached after 5-10 sniffs in most individuals 1. For SNIP measurement, 10 sniffs are usually performed. The SNIP is measured at baseline, visit 7, visit 18 and visit 24. The overall change from baseline to visit 24 will be measured.
Time frame: Baseline, 7 weeks, 18 weeks, 24 weeks
| Milestone | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Started | 8 | 1 |
| Completed | 7 | 0 |
| Not completed | 1 | 1 |
| Withdrew: Withdrawal by subject | 1 | 1 |
Safe, well-tolerated moderate intensity Respiratory Muscle Training (RMT) is in part defined as an RPE between 4-5 and \<6. The RPE is a way of measuring physical activity intensity level. Perceived exertion is how hard the participant feels like their body is working. 0 = rest, 1 = very easy, 2 = easy, 3 = moderate, 4 = somewhat hard, 5 = hard, 6 = harder, 7 = very hard, 8/9 = extremely hard, 10 = maximal.
| Participants | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Number of Participants With Safe, Well-tolerated Moderate Intensity Respiratory Muscle Training (RMT) as Measured by Rating of Perceived Exertion (RPE) | 4 | — |
Safe, well-tolerated moderate intensity Respiratory Muscle Training (RMT) is in part defined as a pain rating of \<4 on a standard 0-10 scale, where 0 = no pain and 10 = the worst pain possible.
| Participants | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Number of Participants With Safe, Well-tolerated Moderate Intensity Respiratory Muscle Training (RMT) as Measured by Pain Score | 6 | — |
Feasibility will be determined by the number of participants able to complete the Respiratory Muscle Training
| Participants | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Number of Participants Able to Complete Respiratory Muscle Training (RMT) | 7 | 0 |
Magnitude of change for our primary outcome measures will be determined using Cohen's measure of effect size (d) as defined by the first equation for single-subject d provided by Busk and Serlin (1992). Simply stated, d is obtained by subtracting the mean of the first assessment from the mean of the second assessment, divided by the standard deviation of the first assessment. Effect size calculations will be determined to compare results from pre-test (M7) to post-test (M18). The investigators will use conservative interpretation guidelines for effect size calculations in which d \< 0.6 is negligible, d ≥ 0.6 modest, d ≥ 1.0 large, and d ≥ 2.0 very large.
| Participants | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Negligible | 5 | — |
| Modest | 1 | — |
| Large | 1 | — |
Magnitude of change for our primary outcome measures will be determined using Cohen's measure of effect size (d) as defined by the first equation for single-subject d provided by Busk and Serlin (1992). Simply stated, d is obtained by subtracting the mean of the first assessment from the mean of the second assessment, divided by the standard deviation of the first assessment. Effect size calculations will be determined to compare results from baseline (M0-M5) to withdrawal (M19-M24). The investigators will use conservative interpretation guidelines for effect size calculations in which d \< 0.6 is negligible, d ≥ 0.6 modest, d ≥ 1.0 large, and d ≥ 2.0 very large.
| Participants | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Negligible | 5 | — |
| Large | 2 | — |
Effective peak cough flow in healthy subjects exceeds values of 360 to 400 L/min. PCF is measured at baseline, visit 7, visit 18 and visit 24. The overall change from baseline to visit 24 will be measured.
No measurements were reported for this outcome.
The sniff nasal inspiratory pressure (SNIP) consists in the measurement of pressure through an occluded nostril during sniffs performed through the contralateral nostril. SNIP is measured through a plug occluding one nostril during sniffs through the contralateral nostril. A plateau in pressure is reached after 5-10 sniffs in most individuals 1. For SNIP measurement, 10 sniffs are usually performed. The SNIP is measured at baseline, visit 7, visit 18 and visit 24. The overall change from baseline to visit 24 will be measured.
No measurements were reported for this outcome.
Collected over Baseline to approximately 24 weeks. Non-serious events are listed at a 0% frequency threshold.
| Group | Deaths | Serious | Other |
|---|---|---|---|
| Minimal to No Respiratory Weakness | 0/8 (0%) | 0/8 (0%) | 5/8 (62.5%) |
| Mild to Moderate Inspiratory Weakness | 0/1 (0%) | 1/1 (100%) | 1/1 (100%) |
| Event | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| Respiratory declineRespiratory, thoracic and mediastinal disorders | 0/8 | 1/1 |
| Event | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness |
|---|---|---|
| DysphoniaGeneral disorders | 0/8 | 1/1 |
| Neck weakness/tightnessMusculoskeletal and connective tissue disorders | 1/8 | 1/1 |
| Seasonal allergies/headacheGeneral disorders | 1/8 | 0/1 |
| DizzinessGeneral disorders | 1/8 | 0/1 |
| NauseaGastrointestinal disorders | 1/8 | 0/1 |
| COVID diagnosisInfections and infestations | 1/8 | 0/1 |
| Fall without injuryGeneral disorders | 1/8 | 0/1 |
| BronchitisRespiratory, thoracic and mediastinal disorders | 1/8 | 0/1 |
| Age, Continuous(years) | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness | Total |
|---|---|---|---|
| Mean | 61.4 ± 11.7 | 73.0 ± 0 | 62.7 ± 11.6 |
| Sex: Female, Male(Participants) | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness | Total |
|---|---|---|---|
| Female | 3 | 0 | 3 |
| Male | 5 | 1 | 6 |
| Ethnicity (NIH/OMB)(Participants) | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness | Total |
|---|---|---|---|
| Hispanic or Latino | 0 | 0 | 0 |
| Not Hispanic or Latino | 8 | 1 | 9 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Race (NIH/OMB)(Participants) | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness | Total |
|---|---|---|---|
| American Indian or Alaska Native | 0 | 0 | 0 |
| Asian | 0 | 0 | 0 |
| Native Hawaiian or Other Pacific Islander | 0 | 0 | 0 |
| Black or African American | 0 | 0 | 0 |
| White | 8 | 1 | 9 |
| More than one race | 0 | 0 | 0 |
| Unknown or Not Reported | 0 | 0 | 0 |
| Region of Enrollment(Participants) | Minimal to No Respiratory Weakness | Mild to Moderate Inspiratory Weakness | Total |
|---|---|---|---|
| United States | 8 | 1 | 9 |
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