RESUMEN
Introduction: Fatigue, postural control impairments, and reduced respiratory capacities are common symptoms in persons diagnosed with Multiple Sclerosis (MS). However, there is a paucity of evidence establishing correlations among these factors. The aim of this study is to analyze respiratory function in persons with MS compared to the control group as well as to analyze the relationship between fatigue, respiratory function and postural control in persons with MS. Materials and methods: A total of 17 persons with MS and 17 healthy individuals were enrolled for this cross-sectional study. The evaluated parameters included fatigue assessed using the Visual Analog Scale-fatigue (VAS-F) and the Borg Dyspnea Scale, postural control assessed through the Mini Balance Evaluation System Test (Mini-BESTest), Berg Balance Scale (BBS), Timed Up and Go (TUG) test, and Trunk Impairment Scale (TIS); and respiratory capacities measured by Maximum Inspiratory Pressure (MIP), Maximum Expiratory Pressure (MEP), Forced Vital Capacity (FVC), Forced Expiratory Volume in the first second (FEV1), FEV1/FVC ratio, Diaphragmatic excursion and diaphragmatic thickness. Results: A very high correlation was observed between the Borg Dyspnoea Scale and the BBS (r = -0.768), TUG (0.867), and Mini-BESTest (r = -0.775). The VAS-F exhibited an almost perfect correlation solely with the TUG (0.927). However, none of the variables related to fatigue exhibited any correlation with the respiratory variables under study. Balance-related variables such as BBS and Mini-BESTest demonstrated a very high and high correlation. Respectively, with respiratory function variables MEP (r = 0.783; r = 0.686), FVC (r = 0.709; r = 0.596), FEV1 (r = 0.615; r = 0.518). BBS exhibited a high correlation with diaphragmatic excursion (r = 0.591). Statistically significant differences were noted between the persons with MS group and the control group in all respiratory and ultrasound parameters except for diaphragmatic thickness. Conclusion: The findings suggest that decreased postural control and balance are associated with both respiratory capacity impairments and the presence of fatigue in persons with MS. However, it is important to note that the alterations in respiratory capacities and fatigue are not mutually related, as indicated by the data obtained in this study. Discrepancies were identified in abdominal wall thickness, diaphragmatic excursion, and respiratory capacities between persons with MS and their healthy counterparts.