Pulmonary Function and Respiratory Muscle Strength in Patients with Multiple Sclerosis

Area of Science:

• Neurology
• Pulmonology
• Rehabilitation Medicine

Background:

• Multiple sclerosis (MS) can lead to decreased muscle strength and physical capacity due to central nervous system demyelination and axonal loss.
• Respiratory impairment may occur in advanced MS, but pulmonary function in earlier stages is not well-described.
• This study investigates pulmonary function and respiratory muscle strength in patients with moderate MS.

Purpose of the Study:

• To describe pulmonary function and respiratory muscle strength in patients with moderate MS.
• To identify associations between respiratory muscle strength and functional capacity.
• To explore the relationship between respiratory function and disease severity (EDSS).

Main Methods:

• A descriptive cross-sectional study of 48 MS patients (mean age 56 ± 11 years, disease duration 24 ± 11 years, median EDSS 4.5).
• Evaluated pulmonary function (spirometry), respiratory muscle strength (MIP, MEP), peak cough flow, and physical capacity (6MWT).
• Assessed subjective breathing and coughing ability and peripheral oxygen saturation.

Main Results:

• Patients exhibited normal spirometry (VC 103 ± 16%, FEV1 95 ± 15%) and peak expiratory flow (89 ± 17%) near the lower limit of normal.
• Respiratory muscle strength (MIP 98 ± 31%, MEP 104 ± 29%) was generally normal but showed significant individual variability.
• Positive associations found between MIP/MEP and pulmonary function; negative association between EDSS and MEP (r = -0.312, p = 0.031). Moderate correlation between MEP and 6MWT (r = 0.399, p = 0.010).

Conclusions:

• Pulmonary function, spirometry, and peak cough flow are normal in mild-to-moderate MS, but respiratory muscle strength varies significantly.
• Impaired respiratory muscle strength is linked to lower functional capacity and greater MS disease severity.
• Findings highlight the importance of assessing respiratory muscle strength in MS management.