Is There a Link Between the Qualitative Descriptors and the Quantitative Perception of Dyspnea in Asthma?

BackgroundThere is no obvious link between qualitative descriptors and overall intensity of dyspnea during bronchoconstriction in patients with asthma.AimsTo determine whether qualitative and quantitative perception of methacholine-induced bronchoconstriction independently contribute to characterizing clinically stable asthma.Material and methodsWe assessed changes in inspiratory capacity, and quantitative (by Borg scale) and qualitative (by a panel of eight dyspnea descriptors) sensations of dyspnea at 20 to 30% fall in FEV1 during methacholine inhalation in 49 asthmatics. Furthermore, we calculated the level of perception of bronchoconstriction at 20% fall in FEV1 (PB20).ResultsDescriptors selected by patients during methacholine inhalation allowed us to define three language subgroups: (1) chest tightness (subgroup A, n = 21); (2) work/effort (subgroup B, n = 7); and (3) both descriptors (subgroup C, n = 13). Eight of the 49 patients (subgroup D) were not able to make a clear-cut distinction among descriptors. The subgroups exhibited similar function at baseline and during methacholine inhalation. Most importantly, patients selected chest tightness to a greater extent (42.85%), and work/effort (14.3%) and both descriptors (26.5%) to a lesser extent at the lowest level of bronchoconstriction (FEV1 fall < 10%) as at 20% fall in FEV1. Thirty-two patients were normoperceivers (PB20 ≥ 1.4 to < 5 arbitrary units [au]), 7 patients were hyperperceivers (PB20 ≥ 5 au), and 10 patients were hypoperceivers (PB20 < 1.4 au). Language subgroups were equally distributed across the perceiver subgroups.ConclusionsIn patients with clinically stable asthma, PB20 and language of dyspnea independently contribute to defining the condition of the disease. However, the possibility that this independence may be due to a β-error should be taken into account.