Inspiratory pressure threshold training for glottal airway limitation in laryngeal papilloma

A single-subject design was used to determine if inspiratory pressure threshold training increases inspiratory muscle strength and reduces the sensation of dyspnea during exercise and speech. The subject was a 23-year-old female with congenital juvenile papilloma which has been in remission for 10 years. A 4-week inspiratory muscle training program was implemented using an inspiratory pressure threshold trainer. The pressure threshold of the trainer was set by the experimenter. The pressure threshold setting of the trainer was based on a percentage of the subject's maximum inspiratory pressure measured prior to training. The average range of the pressure threshold was 40 to 70 cmH2O. In order for inspiratory air to flow, the subject generated inspiratory pressure, independent of airflow rate. Maximum inspiratory pressure (MIP) was the dependent variable used as the index of inspiratory muscle strength. Exercise dyspnea was a dependent variable rated by the subject during a progressive treadmill test. Dyspnea associated with speech was rated following production of a comfortable and loud speech task. MIP increased by 57% following the training program with a 2-scale point reduction in the perception of dyspnea during exercise. Dyspnea during loud speech decreased from moderate to mild. The changes in dyspnea, both during exercise and speech, are directly related to inspiratory muscle strengthening. The results suggest that inspiratory muscle training may improve respiratory related function in patients with restrictive upper airway disorders.