RESPIRATORY MUSCLE TRAINING IN PATIENTS WITHAMYOTROPHIC LATERAL SCLEROSIS: A SYSTEMATIC REVIEW

V.Y. Tan¹, D. Maniam¹, J.Q. Yong¹

¹National Univerity Hospital, Rehabilitation, Singapore, Singapore

Background: Amyotrophic Lateral Sclerosis (ALS) is a neurodegenerative disease characterised by progressive limb and bulbar weakness. As the disease progresses in ALS, respiratory failure remains as one of the leading causes of mortality.There is growing evidence demonstrating that respiratory muscle training (RMT) has improved respiratory function in various neurodegenerative diseases. However, few studies have specifically studied the effects of RMT in ALS and hence standalone high quality research in this area is still scarce.

Purpose: With respiratory insufficiency being one of the primary cause of mortality and morbidity in this population, maintaining respiratory muscle strength should be a key focus for physiotherapy. Therefore, this systematic review aims to determine the effectiveness of RMT, either inspiratory(IMT) or expiratory muscle training (EMT), on ventilatory function, respiratory muscle strength, and functional capacity in patients with ALS.

Methods: The search for papers was conducted in the following electronic databases: MEDLINE (PubMed), Cochrane Central Register of Controlled Trials (Cochrane CENTRAL), Physiotherapy Evidence Database (PEDro), EMBASE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), from inception untilJune 2022.The study included clinical trials published in which inspiratory and/or expiratory muscle strength training were conducted in patients with ALS.The methodological quality of the articles included were assessed using the Physiotherapy Evidence Database (PEDro) scale.

Results: Five clinical trials including 136 patients with ALS were included in this review. All of the studies scored 5 and above on the PEDro scale. Out of the 5 studies, 3 involved IMT while the other 2 were for EMT. The results showed that there were non-significant improvements in Maximal Inspiratory Pressure(MIP) across all IMT studies. For EMT, both studies found that moderate intensity EMT resulted in significant improvements in Maximal Expiratory Pressure (MEP). Only 1 study out of the 5 articles studied the long term effects of respiratory muscle training and found IMT to be a significant predicator of longer survival which increased by 14 months. All 5 clinical trials demonstrated high compliancy rates to their respective RMT interventions in both clinical or home based settings and nil adverse events were reported.

Conclusions: Though there is inconclusive evidence to be certain that RMT benefits patients with ALS, RMT has been found to be safe in this population. Specifically, EMT has been found to yield short term significant results in MEP, though long term effects have yet to be studied. As for IMT, though non-significant improvements were reported in short term studies, longer term analysis suggests IMT prolongs survival in ALS. Further research should look at the development of larger prospective studies assessing long-term clinical benefits of RMT to supplement or change the current perspective of this intervention in clinical practice. Future studies should also investigate the effects of a combined IMT and EMT protocol in patients for maximal benefits.

Implications: RMT is a safe modality and should be started early in the diagnosis of ALS. Physiotherapists should consider implementing a combination of moderate intensity EMT and IMT given the reports of short term benefits and potential to extend survival respectively.

Funding acknowledgements: Nil funding

Keywords:
Respiratory muscle training
Amyotrophic Lateral Sclerosis
Respiratory Physiotherapy

Topics:
Neurology
Cardiorespiratory
Disability & rehabilitation

Did this work require ethics approval? No

Reason: It is a systematic review