It’s important to keep on top of respiratory health in multiple sclerosis.
Impairments in inspiratory and expiratory function frequently occur in patients with multiple sclerosis (MS); even those without overt signs and symptoms of respiratory dysfunction. The causes of respiratory muscle weakness in MS can include neurologic impairment, physical inactivity, steroid-induced myopathy, or demyelination of the respiratory motor pathways.1
Respiratory muscle weakness can lead to fatigue, reductions in lung volume, decreased exercise performance, deleterious effects on quality of life, and impaired ability to cough.1,2 Diminished coughing performance can in turn cause potentially fatal outcomes such as aspiration pneumonia or acute ventilatory failure.3 These significant consequences of respiratory muscle weakness have led researchers to explore the use of respiratory muscle training (RMT) as a rehabilitative therapy in patients with MS. While various modalities such as deep breathing exercises have been studied in clinical trials, the most common form of RMT involves the use of portable resistive threshold devices that increase airflow resistance during inspiration or expiration.4
In an email interview with Neurology Advisor, Matthew N. Bartels, MD, MPH, chairman of the Department of Rehabilitation Medicine at Montefiore Health System in New York City, stated that the clinical benefits of RMT are uncertain. “Aside from directly measured inspiratory and expiratory muscle strength measured via peak inspiratory and expiratory pressures, studies to date have not shown a clear survival or other medical benefit from RMT in MS, as well as in other populations. In order to definitively study RMT in MS, what would be needed is a good placebo-controlled trial – such as a comparison of RMT and a sham RMT – with a longer follow-up looking at respiratory complications over a year or two while assessing objective measures of lung function and sustainability of benefits in a population of patients with MS. It may unfortunately be difficult to do a trial like this, as the intervention may be moderately costly and hard to fund, but it would be technically reasonably simple.”
A recent Cochrane review and meta-analysis of six clinical trials of RMT in patients with MS found low-quality evidence that inspiratory muscle training with a resistive threshold device is moderately effective for improving predicted inspiratory muscle strength. No evidence of benefit was found for resistive expiratory muscle training.3 However, Andrew Ray, PT, PhD, of the Department of Rehabilitation Science at the University of Buffalo, State University of New York, told Neurology Advisor that further evidence is needed before the benefits associated with expiratory muscle training should be discounted. “Other nonrandomized studies in MS and other diseases have shown a benefit associated with expiratory training on cough and peak flows,” he noted. “This means additional well-powered controlled studies need to be performed in MS. The review only included a few studies that included expiratory training and a few studies including inspiratory training, thus demonstrating the lack of well-done studies in this area. Currently, the potential benefits far outweigh the adverse events. Patients cannot get worse from performing the training. They can only get better.”
|Read on: Respiratory Muscle Training in Multiple Sclerosis: Assessing the Evidence|