Clinical pulmonary function testing in Duchenne muscular dystrophy

In Duchenne muscular dystrophy there is a well-established progressive loss of upper and lower extremity muscle function that is evident from the earliest stages of decline and through permanent loss of function. There is not the same visible evidence of decline in respiratory muscle function decline toward respiratory failure; therefore, comprehensive pulmonary function testing provides a critical component of a comprehensive longitudinal respiratory assessment. There are multiple ways of assessing separate inspiratory and expiratory muscle function and also a summative output of each to provide broad information to help identify disease status and guide intervention as appropriate.