%0 Journal Article
%T Data reduction for cough studies using distribution of audio frequency content
%A Antony Barton
%A Patrick Gaydecki
%A Kimberley Holt
%A Jaclyn A Smith
%J Cough
%D 2012
%I BioMed Central
%R 10.1186/1745-9974-8-12
%X 20 subjects were recruited (5 healthy smokers and non-smokers, 5 chronic cough, 5 chronic obstructive pulmonary disease and 5 asthma), fitted with an ambulatory recording system and recorded for 24 hours. The recordings produced were divided into 15 min segments and counted. Periods of inactive audio in each segment were removed using the median frequency and power of the audio signal and the resulting files re-counted.The median resultant segment length was 13.9 s (IQR 56.4 s) and median 24 hr recording length 62.4 min (IQR 100.4). A median of 0.0 coughs/h (IQR 0.0-0.2) were erroneously removed and the variability in the resultant cough counts was comparable to that between manual cough counts. The largest error was seen in asthmatic patients, but still only 1.0% coughs/h were missed.These data show that a system which measures signal activity using the median audio frequency can substantially reduce record lengths without significantly compromising the coughs contained within them.Cough is the commonest symptom reported by patients to doctors and presents as part of the symptom complex of many respiratory diseases [1,2]. Until recent years the study of cough has been restricted by a lack of useful measurement tools, relying mainly upon subjective reporting of cough severity. The development of portable digital sound recording devices has allowed the number of cough sounds to be counted over extended time periods, providing an objective measure of cough rate and new insights into its determinants [3-6]. However, at present, sufficiently accurate algorithms are not in place to allow reliance upon fully automated detection systems. Patient recordings require laborious manual counting with confirmation of cough sounds by experienced observers. To enable studies of a meaningful size, either the present method of manual counting must be made more efficient, or for large studies an automatic system must be developed. The amount of data generated by larger cough studies r
%K Aacoustics
%K Cough sounds
%K Monitoring
%U http://www.coughjournal.com/content/8/1/12