Respiratory Muscle Strength and Endurance Cut-Offs in Multiple Sclerosis

NCT07373704 | Not Yet Recruiting

• 1 other identifier: SelcukU_PT_MS_RESP_ENDURANCE_1
• Study Type: observational
• Target: 40
• Locations: 1 country
• Sites: 1

Brief Summary

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system characterized by inflammation, demyelination, and axonal degeneration. Depending on lesion localization and disease severity, individuals with MS may develop a wide range of neurological manifestations affecting motor and sensory functions. Current evidence indicates that pulmonary function impairments may occur in individuals with MS even in the absence of overt respiratory symptoms. Compared with healthy individuals, people with MS have been reported to exhibit significantly reduced values in several respiratory parameters, particularly respiratory muscle strength. Moreover, these reductions appear to become more pronounced in parallel with increasing Expanded Disability Status Scale (EDSS) scores, regardless of disease duration. Indeed, previous studies have demonstrated that even individuals with MS who have mild disability levels (EDSS 0-4.5) experience significant declines in respiratory muscle strength, pulmonary function, and functional exercise capacity compared with healthy controls. These findings suggest that the respiratory system may be affected not only in the advanced stages of MS but also during the early phases of the disease, with functional impairments emerging before clinically evident respiratory complaints arise. Despite this, the existing literature lacks studies that define clear, clinically applicable cut-off values for respiratory muscle strength and endurance that can discriminate disability levels in individuals with MS. This gap highlights the absence of objective criteria that clinicians can rely on for early detection and for planning targeted rehabilitation interventions. The present study aims to address this gap by identifying optimal cut-off points for respiratory muscle strength and endurance in individuals with MS to facilitate early and accurate discrimination of disability status. By doing so, this research seeks to make an original contribution to the literature. The findings are expected to support the standardization of respiratory assessment processes in clinical practice, thereby improving patient quality of life and enhancing the efficiency of healthcare services. Furthermore, the results will provide a strong scientific basis for integrating respiratory function assessments into MS follow-up protocols and will offer a methodological framework for future intervention-oriented studies.

Conditions

Multiple Sclerosis

Keywords

Multiple Sclerosis; Respiratory Muscle Strength; Respiratory Muscle Endurance; Pulmonary Function; Maximal Inspiratory Pressure; Maximal Expiratory Pressure; Cut-Off Values; EDSS

Outcome Measures

Primary Outcomes (2)

• Respiratory Muscle Strength (Maximal Inspiratory and Expiratory Pressures)

  Respiratory muscle strength will be assessed by measuring maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) using an electronic mouth pressure device. Optimal cut-off values of respiratory muscle strength for discriminating disability status will be determined based on EDSS levels.

  Baseline

• Respiratory Muscle Endurance

  Respiratory muscle endurance will be evaluated using an incremental threshold loading protocol. The highest load sustained for at least one minute and the endurance index will be used to determine optimal cut-off values for distinguishing disability status in individuals with multiple sclerosis.

  Baseline

Secondary Outcomes (10)

• Expanded Disability Status Scale (EDSS)

  Baseline

• Pulmonary Function: Forced Expiratory Volume in 1 Second (FEV₁)

  Baseline

• Pulmonary Function: Forced Vital Capacity (FVC)

  Baseline

• Pulmonary Function: FEV₁/FVC Ratio

  Baseline

• Pulmonary Function: Peak Expiratory Flow (PEF)

  Baseline

Study Arms (1)

Individuals with Multiple Sclerosis

Individuals diagnosed with multiple sclerosis undergoing assessment of respiratory muscle strength, respiratory muscle endurance, pulmonary function, walking performance, fatigue, and quality of life to determine optimal cut-off values for discriminating disability status.

Other: Respiratory Muscle Strength and Endurance Assessment

Interventions

Respiratory Muscle Strength and Endurance Assessment OTHER

Participants will undergo a comprehensive assessment of respiratory muscle function, including respiratory muscle strength measured by maximal inspiratory and expiratory pressures and respiratory muscle endurance evaluated using an incremental threshold loading protocol. Pulmonary function will be assessed by spirometry. These assessments will be conducted to determine optimal cut-off values of respiratory muscle strength and endurance for discriminating disability status in individuals with multiple sclerosis and to examine their associations with clinical outcomes.

Individuals with Multiple Sclerosis

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Adults aged 18 years and older diagnosed with multiple sclerosis who are clinically stable, able to communicate effectively, and eligible for respiratory muscle strength and endurance assessments.

You may qualify if:

• Diagnosed with multiple sclerosis,
• Aged 18 years or older,
• Able to communicate effectively (able to speak, understand, read, and comprehend Turkish),
• No relapse within the past three months,
• Clinically stable for at least the past one month,
• No participation in respiratory-based rehabilitation programs within the past six months,
• Voluntary participation in the study.

You may not qualify if:

• Presence of neurological disorders other than multiple sclerosis,
• Presence of autoimmune diseases other than multiple sclerosis (e.g., rheumatoid arthritis, type 1 diabetes mellitus, systemic lupus erythematosus),
• Presence of chronic cardiac or pulmonary diseases that may affect respiratory muscle strength or pulmonary function, such as chronic obstructive pulmonary disease (COPD), asthma, interstitial lung disease, or heart failure,
• Pregnancy or breastfeeding,
• Inability to comply with the testing procedures.

Sponsors & Collaborators

• Selcuk University: lead

Study Sites (1)

Selcuk University Faculty of Medicine Hospital MS Life Center

Konya, Selcuklu, 42130, Turkey (Türkiye)

Location

Related Publications (8)

• Bosnak-Guclu M, Gunduz AG, Nazliel B, Irkec C. Comparison of functional exercise capacity, pulmonary function and respiratory muscle strength in patients with multiple sclerosis with different disability levels and healthy controls. J Rehabil Med. 2012 Jan;44(1):80-6. doi: 10.2340/16501977-0900.

  PMID: 22234321 BACKGROUND

• Mutluay FK, Gurses HN, Saip S. Effects of multiple sclerosis on respiratory functions. Clin Rehabil. 2005 Jun;19(4):426-32. doi: 10.1191/0269215505cr782oa.

  PMID: 15929512 BACKGROUND

• Altintas A, Demir T, Ikitimur HD, Yildirim N. Pulmonary function in multiple sclerosis without any respiratory complaints. Clin Neurol Neurosurg. 2007 Apr;109(3):242-6. doi: 10.1016/j.clineuro.2006.09.004. Epub 2006 Oct 13.

  PMID: 17046152 BACKGROUND

• Brown TR, Kraft GH. Exercise and rehabilitation for individuals with multiple sclerosis. Phys Med Rehabil Clin N Am. 2005 May;16(2):513-55. doi: 10.1016/j.pmr.2005.01.005.

  PMID: 15893685 BACKGROUND

• Bishop M, Rumrill PD. Multiple sclerosis: Etiology, symptoms, incidence and prevalence, and implications for community living and employment. Work. 2015;52(4):725-34. doi: 10.3233/WOR-152200.

  PMID: 26639011 BACKGROUND

• Tremlett H, Paty D, Devonshire V. Disability progression in multiple sclerosis is slower than previously reported. Neurology. 2006 Jan 24;66(2):172-7. doi: 10.1212/01.wnl.0000194259.90286.fe.

  PMID: 16434648 BACKGROUND

• Calabresi PA. Diagnosis and management of multiple sclerosis. Am Fam Physician. 2004 Nov 15;70(10):1935-44.

  PMID: 15571060 BACKGROUND

• Centonze D, Leocani L, Feys P. Advances in physical rehabilitation of multiple sclerosis. Curr Opin Neurol. 2020 Jun;33(3):255-261. doi: 10.1097/WCO.0000000000000816.

  PMID: 32304436 BACKGROUND

MeSH Terms

Conditions

Multiple Sclerosis

Condition Hierarchy (Ancestors)

Demyelinating Autoimmune Diseases, CNS; Autoimmune Diseases of the Nervous System; Nervous System Diseases; Demyelinating Diseases; Autoimmune Diseases; Immune System Diseases

Study Officials

• İsmail ÖZSOY, Assoc. Prof. Dr.

  Selcuk University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Konya, Türkiye

  STUDY CHAIR

• Zehra KORKUT, Assist. Prof. Dr.

  Selcuk University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Konya, Türkiye

  STUDY CHAIR

• Gülşah ÖZSOY, Assist. Prof. Dr.

  Selcuk University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Konya, Türkiye

  STUDY CHAIR

• Yasemin GEDİKLİ ERTÜRK, MSc. in PT

  Selcuk University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Konya, Türkiye

  STUDY CHAIR

• Selen GÜR ÖZMEN, Assoc. Prof. Dr.

  Bahçeşehir University, Faculty of Health Sciences, Department of Physiotherapy and Rehabilitation, Istanbul, Türkiye

  STUDY CHAIR

• Haluk GÜMÜŞ, Prof. Dr.

  Selçuk University, Faculty of Medicine, Department of Neurology, Konya, Türkiye

  STUDY CHAIR

• Tuğbanur BAYTOK, Dr.

  Selçuk University, Faculty of Medicine, Department of Neurology, Konya, Türkiye

  STUDY CHAIR

• Cahit AYAN, Dr.

  Selçuk University, Faculty of Medicine, Department of Neurology, Konya, Türkiye

  STUDY CHAIR

Central Study Contacts

Mehmet K ALTUNOK, PHD(c) in PT

CONTACT

5558175133; mehmetkaan.altunok@selcuk.edu.tr

Study Design

• Study Type: observational
• Observational Model: OTHER
• Time Perspective: CROSS SECTIONAL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Lecturer

Study Record Dates

• First Submitted: January 15, 2026
• First Posted: January 28, 2026
• Study Start: February 2, 2026
• Primary Completion (Estimated): June 30, 2026
• Study Completion (Estimated): July 30, 2026
• Last Updated: January 28, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

TU (1)