| (b) Constant time 0.5 s, P0.5 | ||
| P0.5 sound parameter | Correlation with cough strength VAS | |
| Free-field microphone | Contact microphone | |
| PW | 0.88 (0.67 to 0.90) | 0.83 (0.46 to 0.85) |
| Ep | 0.77 (0.61 to 0.88) | 0.68 (0.52 to 0.88) |
| RT | 0.32 (−0.09 to 0.66) | 0.44 (−0.02 to 0.71) |
| D | 0.17 (0.00 to 0.31) | 0.17 (0.00 to 0.31) |
| Fp | 0.43 (0.21 to 0.65) | 0.30 (0.00 to 0.64) |
| BW | 0.03 (−0.62 to 0.32) | 0.12 (−0.24 to 0.39) |
| Fc | 0.34 (0.06 to 0.72) | 0.66 (0.31 to 0.78) |
Data are presented as median (IQR) within-subject Spearman's correlation coefficients between cough sound and cough strength VAS. Individual correlation coefficients are presented in online supplementary table 7. (PW, power; Ep, peak energy; RT, rise time; D, duration; Fp, peak frequency; BW, bandwidth; Fc, centroid frequency).