Multiple Sclerosis is a demyelinating disease of the central nervous system that often causes respiratory dysfunctions. Patients with severe stages of MS, in fact, can have respiratory muscle weakness. This can manifest in a number of different ways, including via a patients’ cough. The ability to cough is a function that is essential for airway defence. As coughing is a neural function, it is often impaired in MS patients.

Prior studies have shown some impact of respiratory muscle training (RMT) on improving respiratory muscle strength. In the following study, expiratory muscle strength training (EMST) is tested for improved expiratory pressure, pulmonary and cough function in MS patients as well as healthy controls.

Key Findings

• MS is a demyelinating disease of the central nervous system, and often causes respiratory dysfunctions.
• As cough is a neural function, it is often impaired in MS patients.
• 8 weeks of expiratory muscle training (EMT) improved expiratory muscle strength and cough airflow.
• Increased expiratory muscle strength was still measurable 4 weeks after EMT.

Patient Impact

Increased expiratory muscle strength was still measurable 4 weeks after EMT.

Study Methods

The following were all assessed throughout the course of the study:

• Pulmonary functions
• Maximal expiratory pressure
• Maximal voluntary cough

These were assessed in MS patients and healthy controls before and after eight weeks of EMST. A follow-up assessment was performed after four weeks of detraining (i.e. four weeks after attenuation of training).

Study Results

Maximal expiratory pressure significantly increased in both MS patients and healthy controls as a result of EMST, and the effect remains after detraining. No significant improvements were observed in maximal voluntary cough after EMST training, however a significant improvement in cough airflow was seen in MS patients with mild to moderate disability levels. This returned to baseline after detraining.

EMST significantly improves maximal expiratory pressure in MS patients, and maintains a prolonged effect after detraining. No significant improvements were seen in maximal voluntary cough in healthy control or MS patients. EMST results in a significant improvement of cough airflow in MS patients, however, with mild to moderate disease. This suggests that EMST could be a good method to try and preserve respiratory function in patients with MS.

References

Chiara, T et al. Expiratory Muscle Strength Training in Persons With Multiple Sclerosis Having Mild to Moderate Disability: Effect on Maximal Expiratory Pressure, Pulmonary Function, and Maximal Voluntary Cough. Archives of physical medicine and rehabilitation 87.4 (2006): 468–473. PMC. Web. 15 Sept. 2015.