Acoustic analysis of capsaicin-induced cough in patients with chronic persistent cough and healthy subjects

P. Suwanprathes, M. C. Ngu, A. Breslin, A. J. Ing, C. M. Chow, C. W. Thorpe

Research output: Contribution to journalArticlepeer-review

Abstract

The purpose of the study was to compare the acoustic properties of capsaicin-induced cough between chronic persistent cough (CPC) patients and healthy subjects. Methods: 13 CPC patients and 12 healthy normal subjects were studied. The capsaicin cough test was performed using a single inhalation technique. A total of 922 coughs were recorded at a sampling rate of 11kHz from the CPC patients and 401 from the normals. The power spectral density (PSD) of each cough was then computed and the cough sound characterised by calculating the 25th, 50th and 75th percentiles of the PSD, the mean frequency, the total acoustic power, and the cough duration. Results: The table shows the mean, standard deviation, and range across subjects for each of the variables. Variable Normal Mean (S.D.) range CPCMean (S.D.) range Duration (s) 0.4(0.1) 0.3-0.5 0.4(0.1) 0.3-0.8 Power (dB) 7.6(2.9) 2.1-13.4 8.7(4.2) 1.9-14.9 Mean f (kHz) 1.4 (0.4) 0.9 - 2.0 1.3 (0.4) 0.7 -1 .9 25th % (kHz) 0.4 (0.2) 0.3 - 1.0 0.5 (0.2) 0.3 - 0.7 50th% (kHz) 1.0(0.4) 0.5-1.9 0.9(0.3) 0.5-1.5 75th%(kHz) 2.0(0.7) 1.1-3.3 1.7(0.6) 0.8-2.9 Conclusions: Although there is no overall significant difference in the variables examined, there was a trend towards greater power and lower frequencies for sound energy in CPC patients. The wide overlap between patients and normals suggest that cough threshold and not cough sound characteristics differentiate the two groups.

Original languageEnglish
JournalRespirology
Volume4
Issue numberSUPPL. 1
Publication statusPublished - 1999
Externally publishedYes

Keywords

  • Acoustic analysis
  • Capsaicin
  • Cough
  • Power spectral density

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