Purpose: The aim of our study was to assess the
long-term effects of specific inspiratory muscle training (IMT) in
patients with neuromuscular disorders (NMDs) who have various degrees
of respiratory impairment.
Patients and methods:
Twenty-seven patients with NMDs (Duchenne’s muscular dystrophy, 18
patients; spinal muscular atrophy, 9 patients) underwent 24 months of
IMT. Patients were divided into three groups according to their vital
capacity (VC) values. VC was measured as the parameter for the
respiratory system involvement of the disease. Maximal inspiratory
pressure (Pimax) was assessed as the parameter for
respiratory muscle strength, and the results of the 12-s maximum
voluntary ventilation test (12sMVV) were assessed as the parameter for
respiratory muscle endurance. Pulmonary and inspiratory muscle function
parameters were assessed 6 months before training, at the beginning of
training, and then every 3 months.
Pimax values improved in group A (VC, 27 to 50% predicted)
from 51.45 to 87.00 cm H2O, in group B (VC, 51 to 70%
predicted) from 59.38 to 94.4 cm H2O, and in group C (VC,
71 to 96% predicted) from 71.25 to 99.00 cm H2O. The
12sMVV values improved in group A from 52.69 to 69.50 L/min, in group B
from 53.18 to 62.40 L/min, and in group C from 59.48 to 70.5 L/min. For
all three groups, there was a significant improvement of
Pimax (p < 0.007) and 12sMVV (p < 0.015) until the
10th month when a plateau phase was reached with no decline in the
following month until the end of training.
With IMT, respiratory muscle function can be improved in the long term
of up to 2 years.