The effects of inspiratory muscle training in adults with muscular dystrophy

Background/Aims Patients with muscular dystrophy usually have impaired lung function and respiratory muscle strength, leading to pneumonia and respiratory failure, which are significant causes of morbidity and mortality. Inspiratory muscle training might be a safe adjunct treatment to increase the strength and endurance of weakened respiratory muscles. The researchers have developed a new protocol for inspiratory muscle training and evaluated its effect on inspiratory muscle strength and coughing capacity. Methods A total of 12 participants diagnosed with muscle dystrophy and decreased maximal inspiratory pressure (<60 cmH 2O) participated in this prospective study. Training was individually tailored, starting with low resistance levels and progressing according to tolerance and symptoms. The primary outcome measure was maximal inspiratory pressure. Secondary outcomes were maximal expiratory pressure, peak cough flow and the feasibility of the intervention. Results There were two participants who did not complete the study, and three were lost to follow-up; therefore, only seven patients finished the intervention. In these patients, the authors found a statistically significant improvement in the maximal inspiratory pressure (P=0.018) and peak cough flow (P=0.046) after 3 months of training. There was also an improvement in the maximal expiratory pressure, although this was not statistically significant (P=0.176). Median compliance to training was 99% (94.5-100). Conclusions This intervention led to statistically significant improvements in inspiratory muscles strength and coughing capacity in patients with muscular dystrophy. The results were significantly positive and contribute to the evidence in support of this underused, yet possibly beneficial, treatment, although larger randomised controlled trials are required to verify this.