Inspiratory Muscle Training in Individuals With Multiple Sclerosis

Comparison of the Effects of High-Intensity and Low-Intensity Inspiratory Muscle Training in Individuals With Multiple Sclerosis

Multiple sclerosis (MS) is a chronic disease affecting the central nervous system, characterized by inflammation, demyelination, and axonal degeneration, and primarily affects young adults. Muscle weakness, sensory disturbances, spasticity, pain, visual impairment, ataxia, fatigue, cognitive dysfunction, and respiratory complications are among the most commonly reported symptoms in individuals with MS. Although inspiratory muscle training has been shown to have beneficial effects in individuals with MS, the effects of different inspiratory muscle training intensities on respiratory muscle strength and pulmonary function have not been sufficiently investigated.

The primary aim of this study is to investigate the effectiveness and clinical feasibility of high-intensity interval inspiratory muscle training in individuals with MS. The secondary aim is to compare the effects of high-intensity interval inspiratory muscle training, low-intensity inspiratory muscle training, and conventional rehabilitation on respiratory muscle strength, pulmonary function, cough effectiveness, exercise capacity, lower extremity functional muscle strength, balance, fatigue, dysphagia severity, sleep quality, and quality of life in individuals with MS.

Participants will be randomly assigned to one of three groups: a high-intensity interval inspiratory muscle training group, a low-intensity inspiratory muscle training group, or a conventional rehabilitation group. All three groups will receive conventional rehabilitation, while the inspiratory muscle training groups will additionally receive their respective inspiratory muscle training programs. This study aims to be the first randomized controlled trial to evaluate the effects of high-intensity interval inspiratory muscle training in individuals with MS.

Study Overview

• Status: Not yet recruiting
• Conditions: Multiple Sclerosis; Inspiratory Muscle Training
• Intervention / Treatment: Behavioral: High intensity interval IMT; Behavioral: Low intensity IMT; Behavioral: Conventional rehabilitation

Detailed Description

Multiple sclerosis (MS) is a chronic autoimmune disease affecting the central nervous system. Although the pathogenesis of the disease is not fully understood, genetic and environmental factors are thought to contribute to its development. Demyelinating plaques, the primary pathological hallmark of MS, are most commonly found in the optic nerves, brainstem, spinal cord, and periventricular white matter. The clinical manifestations of the disease vary depending on the regions of the central nervous system affected and the extent of inflammation and axonal demyelination. Respiratory function and respiratory muscle strength have been shown to be lower in individuals with MS compared with healthy individuals. The risk of death due to respiratory complications is approximately 12 times higher in the MS population than in the general population, and 47% of MS-related deaths are attributed to respiratory complications. These findings highlight the critical importance of early interventions targeting respiratory function.

Although inspiratory muscle training (IMT) has been shown to improve respiratory function, its effects on functional outcomes in individuals with MS have not been sufficiently investigated. However, these functional outcomes are important for improving quality of life and optimizing rehabilitation in individuals with MS. Furthermore, because studies investigating IMT in individuals with MS are limited, the optimal training protocol in terms of training frequency, intensity, and duration has not yet been clearly established. Recent studies have demonstrated that high-intensity interval IMT is effective in improving respiratory function, respiratory muscle strength, and functional capacity in individuals with chronic obstructive pulmonary disease, bronchiectasis, and heart failure, and that it is well tolerated by patients. To the best of our knowledge, no study has investigated the effects of this approach in individuals with MS.

This study is designed as a randomized controlled trial. A total of 48 individuals diagnosed with MS will be randomly assigned to one of three groups: high-intensity interval IMT, low-intensity IMT, or conventional rehabilitation. The intervention period will last 8 weeks. All three groups will receive conventional rehabilitation consisting of aerobic and resistance exercises. In addition, the IMT groups will receive either high-intensity interval IMT or low-intensity IMT. The primary outcome measures of the study are respiratory muscle strength, pulmonary function, and cough strength. Secondary outcome measures include exercise capacity, lower extremity functional muscle strength, balance, fatigue, dysphagia severity, sleep quality, and quality of life.

• Study Type: Interventional
• Enrollment (Estimated): 48
• Phase: Not Applicable

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Diagnosis of multiple sclerosis (MS) according to the 2024 McDonald criteria
• Expanded Disability Status Scale (EDSS) score ≥2 and <6
• Age between 18 and 65 years
• Mini-Mental State Examination (MMSE) score >24
• Willingness to participate in the study

Exclusion Criteria:

• Experiencing an MS relapse within the past three months
• Presence of chronic cardiac or pulmonary diseases that may affect respiratory muscle strength and function, such as COPD, asthma, interstitial lung disease, or heart failure
• Presence of pulmonary infection
• Presence of orthopedic problems
• Presence of psychiatric disorders
• Pregnancy

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: High intensity interval IMT group; High-intensity interval IMT and conventional rehabilitation	Behavioral: High intensity interval IMT; Participants with multiple sclerosis (MS) in this group will perform high intensity interval inspiratory muscle training (IMT) for 8 weeks, three times per week (one supervised by a physiotherapist and two home-based sessions). The protocol consists of 7 cycles of 2 minutes of exercise followed by 1 minute of rest, with each session lasting 21 minutes. Training intensity will start at 30% of maximal inspiratory pressure (MIP) and progressively increase to 70% by the third week. From week 4 onward, intensity will be maintained at 70% of MIP and adjusted according to tolerance, based on a Borg scale rating of 3-5. In addition, participants in this group will receive a conventional rehabilitation program for 8 weeks, consisting of three sessions per week: one supervised session conducted by a physiotherapist and two supervised home-based sessions.
Experimental: Low intensity IMT group; Low intensity IMT and conventional rehabilitation	Behavioral: Low intensity IMT; Participants with multiple sclerosis (MS) in this group will perform low intensity inspiratory muscle training (IMT) for 8 weeks, consisting of five sessions per week: one supervised by a physiotherapist and four home-based supervised sessions. The training will be performed as two daily sessions of 15 minutes each, totaling 30 minutes per day. Low intensity IMT will be conducted at 30% of maximal inspiratory pressure (MIP). Training intensity will be reassessed and adjusted to 30% of MIP every two weeks during supervised sessions, based on repeated MIP measurements. During training, participants will be instructed to maintain a seated position with the upper chest and shoulders in a relaxed posture. In addition, participants in this group will receive a conventional rehabilitation program for 8 weeks, consisting of three sessions per week: one supervised session conducted by a physiotherapist and two supervised home-based sessions.
Active Comparator: Conventional rehabilitation	Behavioral: Conventional rehabilitation; Participants in this group will undergo a conventional rehabilitation program for 8 weeks, consisting of three sessions per week: one supervised by a physiotherapist and two home-based supervised sessions. Each session will last approximately 40 minutes. The program will include warm-up exercises, aerobic exercises, strengthening exercises, balance exercises, and cool-down exercises.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Maximal inspiratory pressure (MIP)	In our study, respiratory muscle strength will be assessed using an electronic mouth pressure measurement device (MicroRPM Respiratory Pressure Meter). For maximal inspiratory pressure (MIP) measurement, participants will be asked to wear a nose clip and perform a maximal inspiratory effort lasting at least 1.5 seconds through a mouthpiece after maximal expiration. Measurements will be performed in a seated position with rest intervals between attempts. The highest value obtained from three consecutive trials will be recorded in cmH₂O. The best value will also be expressed as a percentage of predicted normal values according to age and sex.	From baseline to the end of the intervention at 8 weeks
Maximal expiratory pressure (MEP)	In our study, respiratory muscle strength will be assessed using an electronic mouth pressure measurement device (MicroRPM Respiratory Pressure Meter). For maximal expiratory pressure (MEP) measurement, participants will be asked to wear a nose clip and perform a maximal expiratory effort lasting at least 1.5 seconds through a mouthpiece after maximal inspiration. Measurements will be performed in a seated position with rest intervals between attempts. The highest value obtained from three consecutive trials will be recorded in cmH₂O. The best value will also be expressed as a percentage of predicted normal values according to age and sex.	From baseline to the end of the intervention at 8 weeks
Forced Vital Capacity (FVC)	The pulmonary function test will be performed using the COSMED Pony FX device in accordance with the American Thoracic Society and European Respiratory Society guidelines.	From baseline to the end of the intervention at 8 weeks
Forced Expiratory Volume (FEV1)	The pulmonary function test will be performed using the COSMED Pony FX device in accordance with the American Thoracic Society and European Respiratory Society guidelines.	From baseline to the end of the intervention at 8 weeks
Tiffeneau Index (FEV1/FVC)	The pulmonary function test will be performed using the COSMED Pony FX device in accordance with the American Thoracic Society and European Respiratory Society guidelines.	From baseline to the end of the intervention at 8 weeks
Peak Expiratory Flow (PEF)	The pulmonary function test will be performed using the COSMED Pony FX device in accordance with the American Thoracic Society and European Respiratory Society guidelines.	From baseline to the end of the intervention at 8 weeks
Cough strength	For assessment of cough strength, peak cough flow (PCF) will be measured using a peak flow meter (ExpiRite® Peak Flow Meter, China).	From baseline to the end of the intervention at 8 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Exercise capacity	Functional capacity is assessed using the 6-Minute Walk Test according to the criteria of the American Thoracic Society. Participants are instructed to walk as fast as possible, but without running, at their own pace along a 30-meter flat corridor for 6 minutes. The distance covered is recorded in meters.	From baseline to the end of the intervention at 8 weeks
Lower Extremity Functional Capacity	Lower extremity functional capacity will be assessed using the Five Times Sit-to-Stand Test. Participants will be seated in a chair without armrests, with their arms crossed over the chest, and will be instructed to stand up and sit down five times as quickly as possible. The time required to complete the test will be recorded.	From baseline to the end of the intervention at 8 weeks
Balance	Balance will be assessed using the Mini-BESTest. The Mini-BESTest is a 14-item short version of the Balance Evaluation Systems Test (BESTest) designed to assess static and dynamic balance impairments and underlying postural control mechanisms. It includes four domains: anticipatory postural control, reactive postural control, sensory orientation, and dynamic gait. Each item is scored from 0 to 2, with a total score ranging from 0 to 28, where higher scores indicate better balance performance.	From baseline to the end of the intervention at 8 weeks
Balance	Balance will be assessed using the Activities-specific Balance Confidence (ABC) Scale. The ABC Scale will be used to assess balance confidence during daily activities. Participants will rate their confidence in performing 16 different activities on a scale from 0% (no confidence) to 100% (complete confidence). The total score is calculated by averaging item scores, with higher scores indicating lower fear of falling.	From baseline to the end of the intervention at 8 weeks
Fatigue level	Fatigue will be assessed using the Fatigue Severity Scale (FSS). The FSS consists of 9 items rated on a 7-point Likert scale, where 1 indicates strong disagreement and 7 indicates strong agreement. Participants will rate the extent to which they agree with each statement. The total score is calculated by averaging the scores of all items. Higher scores indicate greater fatigue severity. A mean score of ≥4 is considered to indicate severe fatigue.	From baseline to the end of the intervention at 8 weeks
Dysphagia severity	Dysphagia severity will be assessed using the Eating Assessment Tool (EAT-10). The EAT-10 consists of 10 items rated on a 5-point scale ranging from 0 (no problem) to 4 (severe problem). The total score ranges from 0 to 40, with higher scores indicating greater swallowing impairment and increased risk of dysphagia.	From baseline to the end of the intervention at 8 weeks
Sleep quality	Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI). The PSQI evaluates sleep quality over the past month and consists of 24 items. Nineteen items are self-rated by the participant, while 5 items are completed by a bed partner or roommate. Each item is scored on a scale from 0 to 3, and the total score ranges from 0 to 21. A total score of ≤5 indicates good sleep quality, while a score of >5 indicates poor sleep quality.	From baseline to the end of the intervention at 8 weeks
The Multiple Sclerosis Quality of Life-54 (MSQOL-54)	Quality of life will be assessed using the Multiple Sclerosis Quality of Life (MSQOL-54) scale. The MSQoL consists of two main domains: Composite Physical Health (CPH) and Composite Mental Health (CMH). The CPH domain includes eight subdomains (physical health, role limitations due to physical problems, pain, fatigue, social function, health perception, health distress, and sexual function), while the CMH domain includes five subdomains (emotional health, role limitations due to emotional problems, health distress, cognitive function, and overall quality of life. Both domains are scored on a 0-100 scale, with higher scores indicating better quality of life.	From baseline to the end of the intervention at 8 weeks

Collaborators and Investigators

• Sponsor: Istanbul University - Cerrahpasa

Study record dates

Study Major Dates

• Study Start (Estimated): August 1, 2026
• Primary Completion (Estimated): August 1, 2027
• Study Completion (Estimated): January 1, 2028

Study Registration Dates

• First Submitted: June 20, 2026
• First Submitted That Met QC Criteria: June 26, 2026
• First Posted (Actual): June 29, 2026

Study Record Updates

• Last Update Posted (Actual): June 29, 2026
• Last Update Submitted That Met QC Criteria: June 26, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: multiple sclerosis; inspiratory muscle training; respiratory muscle strength; respiratory muscle training
• Additional Relevant MeSH Terms: Nervous System Diseases; Autoimmune Diseases; Immune System Diseases; Demyelinating Autoimmune Diseases, CNS; Autoimmune Diseases of the Nervous System; Demyelinating Diseases; Multiple Sclerosis
• Other Study ID Numbers: ZApaydın-1

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No