Methacholine-Induced Cough in the Absence of Asthma: Insights From Impulse Oscillometry
Bibliographic record
Abstract
The pathophysiologic differences between methacholine-induced cough but normal airway sensitivity (COUGH) and healthy individuals (CONTROL) are incompletely understood and may be due to differences in the bronchodilating effect of deep inspirations (DIs). The purpose of this study is to compare the bronchodilating effect of DIs in individuals with classic asthma (CA), cough variant asthma (CVA), and COUGH with CONTROL and to assess impulse oscillometry (IOS) measures as predictors of the bronchodilating effect of DIs. Methods: 43 adults (18 female; 44.8 ± 12.3 years (Mean ± SD); n=11 CA, n=10 CVA, n=7 COUGH, n=15 CONTROL) underwent modified high-dose methacholine challenge, with IOS and partial/maximal expiratory flow volume maneuvers (PEFV/MEFV; used to calculate DI Index) to a maximum change (Δ) in FEV1 of 50% from baseline (MAX). Cough count and dyspnea were measured at each dose. The relation between spirometry, lung volume and IOS parameters and DI Index was assessed at baseline and MAX using linear regression analysis. Results: Cough frequency, dyspnea intensity and baseline peripheral resistance (R5-R20) were significantly greater in COUGH compared with CONTROL (p=0.006, p=0.029 and p=0.035 respectively). At MAX, the DI Index was significantly lower in COUGH (0.01 ± 0.36) compared with CA (0.67 ± 0.97, p=0.008), CVA (0.51 ± 0.73, p=0.012) and CONTROL (0.68 ± 0.45, p=0.005). R5-R20 and resonant frequency (Fres) were independent IOS predictors of the DI Index. Conclusion: The bronchodilating effect is impaired in COUGH and preserved in mild CA, CVA and CONTROL. Increased peripheral airway resistance and decreased resonant frequency are associated with a decreased DI Index. COUGH is a clinical phenotype distinct from healthy normals and asthma.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.001 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".