Table 1.

Practical recommendations for inspiratory and expiratory muscle testing in LOPD. LLN, lower limit of normal; MEP, maximal expiratory pressure; MIP, maximal inspiratory pressure; PCF, peak cough flow; SNIP, sniff nasal inspiratory pressure; TLC, total lung capacity; VC, vital capacity; PFT, pulmonary function testing; IVC, inspiratory vital capacity; SVC, slow vital capacity; ERV, expiratory reserve volume; IRV inspiratory reserve volume; TV, tidal volume; TLC, total lung capacity; RV, residual volume. Normal values are derived from [33].

Test	Device/Method	LLN	Significance	Recommendations
MEP	Manometer	Females 70 cm H2O, males 100 cm H2O	Expiratory muscle strength	First-line, at least annually
PCF	Peak flow meter	270 L/min, airway clearance impaired if 160–270 L/min, airway clearance impossible if <160 L/min	Reduced vital capacity Reduced inspiratory and expiratory muscle strength	First-line, at least annually widely available
MIP	Manometer	Females 70 cm H2O, males 80 cm H2O	Inspiratory muscle strength	First-line, at least annually
SNIP	Manometer	Females 60 cm H2O, males 70 cm H2O	Inspiratory muscle strength	Surrogate of MIP if weakness of the orbicularis oris muscle is present
VC	Spirometry	Upright > 80% of predicted VC, supine > 80% of upright VC	IRV + TV + ERV (global test of lung volume and respiratory muscle performance)	First-line, at least annually