Effects of 8-week, interval-based inspiratory muscle training and breathing retraining in patients with generalized myasthenia gravis.
OBJECTIVE
To assess the effect of interval-based inspiratory muscle training (IMT) combined with breathing retraining (BR) in patients with generalized myasthenia gravis (MG) in a partial home program.


METHODS
A randomized controlled trial with blinding of outcome assessment.


METHODS
A secondary-care respiratory clinic.


METHODS
Twenty-seven patients with generalized MG were randomized to a control group or a training group.


METHODS
The training group underwent interval-based IMT associated with BR (diaphragmatic breathing [DB] and pursed-lips breathing [PLB]) three times a week for 8 weeks. The sessions included 10 min each of DB, interval-based IMT, and PLB. Interval-based IMT consisted of training series interspersed with recovery time. The threshold load was increased from 20 to 60% of maximal inspiratory pressure (P(Imax)) over the 8 weeks.


RESULTS
Lung function, respiratory pattern, respiratory muscle strength, respiratory endurance, and thoracic mobility were measured before and after the 8 weeks. The training group improved significantly compared to control group in P(Imax) (p = 0.001), maximal expiratory pressure (P(Emax)) [p = 0.01], respiratory rate (RR)/tidal volume (V(T)) ratio (p = 0.05), and upper chest wall expansion (p = 0.02) and reduction (p = 0.04). Significant differences were seen in the training group compared to baseline P(Imax) (p = 0.001), P(Emax) (p = 0.01), maximal voluntary ventilation (p = 0.02), RR/V(T) ratio (p = 0.003), Vt (p = 0.02), RR (p = 0.01), total time of RR (p = 0.01), and upper chest wall expansion (p = 0.005) and reduction (p = 0.005). No significant improvement was seen in lower chest wall or lung function.


CONCLUSIONS
The partial home program of interval-based IMT associated with BR is feasible and effective in patients with generalized MG. Improvements in respiratory muscle strength, chest wall mobility, respiratory pattern, and respiratory endurance were observed.
Fregonezi
Guilherme Augusto de Freitas
GA
Departament de Pneumology, Area de Rehabilitación Respiratoria, Hospital de la Santa Creu i de Sant Pau Av, Sant Antoni Maria Claret, 167 08025, Barcelona, Spain. gfreitas@hsp.santpau.es
Resqueti
Vanessa Regiane
VR
Güell
Rosa
R
Pradas
Jesus
J
Casan
Pere
P
D000328:Adult; D000368:Aged; D001945:Breathing Exercises; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009157:Myasthenia Gravis / Q000534:rehabilitation*; D010807:Physical Endurance; D012129:Respiratory Function Tests; D015656:Respiratory Mechanics; D016037:Single-Blind Method