Effects of respiratory muscle training on respiratory function, trunk control and fatigue in multiple sclerosis

Multiple sclerosis (MS) is a chronic condition affecting the central nervous system, often causing fatigue, postural instability, and respiratory dysfunction. This study aims to evaluate the effects of a combined inspiratory and expiratory respiratory muscle training (RMT) program on respiratory function, trunk control, balance, and clinical fatigue in patients with MS. A quasi-experimental clinical trial was conducted with 27 participants diagnosed with MS. The experimental group (EG) underwent respiratory muscle training (RMT) using the Threshold Inspiratory Muscle Trainer (IMT) and the Positive Expiratory Pressure (PEP) devices (Respironics^®, Phillips), in addition to standard therapy, while the control group (CG) received standard therapy only. Pre- and post-intervention measurements included spirometry, maximum inspiratory pressure (MIP), maximum expiratory pressure (MEP), ultrasound for abdominal muscles thickness, diaphragm thickness and diaphragmatic excursion, and scales for balance (Berg Balance Scale) and trunk control (Trunk Impairment Scale). The EG showed significant improvements in the FEV1/FVC ratio, MEP, and trunk control scores, particularly in the dynamic and coordination subscales of the Trunk Impairment Scale. However, no significant changes were observed in fatigue levels or abdominal muscles thickness. The RMT program enhanced respiratory function and trunk control in MS patients, demonstrating its potential as a therapeutic intervention. Further studies are needed to explore the long-term effects of RMT in MS rehabilitation.