Every breath counts! : Inspiratory muscle training in children with neuromuscular diseases: a cross-over randomised controlled trial

Progressive respiratory muscle weakness and ineffective cough contributes to morbidity and mortality in children with neuromuscular diseases (NMD). Inspiratory muscle training (IMT) aims to preserve or improve respiratory muscle strength and reduce respiratory morbidity. This study aimed to determine the safety and efficacy of IMT in children with NMD. A randomised cross-over study compared three-month intervention (IMT) with control periods. During the intervention, children with NMD (5-18 years) from two provinces in South Africa performed 30 breaths (at 30% of inspiratory muscle strength (Pimax)) with an electronic threshold device, twice daily. During the control period participants did not perform any IMT. Twenty-three participants (median (IQR) age of 12.33 (10.03-14.17) years), mostly male (n=20) and non-ambulant (n=14) were included. No adverse events related to IMT were reported. There was no evidence of a difference in median patient hospitalisation and respiratory tract infection rates between control and intervention periods (p=0.60; p=0.21). During IMT, Pimax and peak cough flow improved with a mean (SD) of 14.57 (±15.67) cmH ₂O and 32.27 (±36.60) L/min, compared to a change of 3.04(±11.93)cmH ₂O (p=0.01) and -16.59 (±48.29) L/min (p=0.0005) during the control period. There was no evidence of change in spirometry, functional ability and total health-related quality of life scores following intervention. Patient satisfaction with IMT was high (median 8/10 (IQR 5-10)) and adherence was good. A three-month IMT programme in children with NMD is well tolerated, appears to be safe and is associated with a significant improvement in respiratory muscle strength and cough efficacy.