The relationship between cough sound, flow and oesophageal pressure
| Sound parameter | Sound analysis time window | ||
| P1 | P1–3 | P0.5 | |
|---|---|---|---|
| (a) Flow | |||
| PW | 0.88 (0.78 to 0.93) | 0.82 (0.60 to 0.90) | 0.88 (0.79 to 0.92) |
| Ep | 0.87 (0.78 to 0.92) | 0.81 (0.56 to 0.90) | 0.87 (0.79 to 0.91) |
| RT | 0.31 (0.02 to 0.48) | 0.01 (−0.18 to 0.3) | 0.23 (−0.05 to 0.42) |
| D | 0.29 (−0.11 to 0.59) | 0.60 (0.23 to 0.82) | N/A |
| Fp | 0.11 (−0.25 to 0.34) | 0.35 (0.07 to 0.53) | 0.17 (−0.06 to 0.45) |
| BW | −0.24 (−0.53 to 0.11) | 0.05 (−0.16 to 0.35) | −0.10 (−0.35 to 0.19) |
| Fc | 0.49 (0.25 to 0.71) | 0.63 (0.26 to 0.79) | 0.48 (0.19 to 0.78) |
| (b) Oesophageal pressure | |||
| PW | 0.89 (0.84 to 0.95) | 0.85 (0.65 to 0.91) | 0.89 (0.81 to 0.94) |
| Ep | 0.89 (0.82 to 0.95) | 0.85 (0.58 to 0.93) | 0.89 (0.82 to 0.94) |
| RT | 0.35 (−0.04 to 0.45) | 0.05 (−0.33 to 0.53) | 0.23 (−0.13 to 0.5) |
| D | 0.23 (−0.11 to 0.54) | 0.70 (0.47 to 0.84) | N/A |
| Fp | 0.06 (−0.30 to 0.41) | 0.36 (0.12 to 0.60) | 0.26 (−0.11 to 0.46) |
| BW | −0.40 (−0.58 to 0.10) | 0.06 (−0.13 to 0.39) | −0.15 (−0.43 to 0.24) |
| Fc | 0.53 (0.22 to 0.76) | 0.68 (0.48 to 0.82) | 0.53 (0.25 to 0.80) |
Data presented as median (IQR) within-subject Spearman’s correlation coefficients for patients with chronic cough and healthy controls combined. The correlations were similar when patients and controls were analysed separately (see online supplementary tables 1–4). Sound was recorded with free-field microphone, with PW, power; Ep, peak energy; RT, rise time; D, duration; Fp, peak frequency; BW, bandwidth; Fc, centroid frequency.