Abstract
Traditional measures of respiratory function in children with Duchenne muscular dystrophy (DMD) are based on maximal inspiratory pressure (PImax) and vital capacity (VC). Sniff nasal inspiratory pressure (SNIP) measurements are easily performed by young children with neuromuscular disorders. The clinical value of SNIP in the longitudinal assessment of respiratory weakness remains to be assessed. Objective: to longitudinally assess the change in SNIP, PImax and VC with age in DMD children. We hypothesized that their longitudinal assessment would show an earlier decline in SNIP than VC.
A 3-year, prospective follow-up at 6-months intervals of 33 DMD, steroid naive, 5-to-20 year-old, was analysed using a linear mixed model.
SNIP measurements were reliable (within session coefficient of variation: 8%). SNIP and VC increased until 10.5 and 12.5 years of age, respectively, and declined thereafter, while PImax did not change with age.
SNIP was an earlier marker of decline in respiratory muscle strength (at 10.5 years) than VC (at 12.5 years) in young DMD. SNIP longitudinal assessment is useful in the detection of inspiratory strength decline in young DMD when VC values remain within normal values and as outcome measure in clinical trials for emerging therapeutics in young DMD from the age of 5.
- ERS
