title: Original waveform of lung sound crackles: a case study of the effect of high-pass filtration.
abstract: In lung sound research, low-frequency noise usually disturbs the sound signal being recorded. Some researchers therefore use high-pass filtration before the final analysis. In this study, the effect of digital and analog high-pass filtration on the morphology of the lung sound crackles is evaluated. The original nonprefiltered crackle waveform is presented, and the effect of the high-pass filtration on the crackle waveform characteristics is elucidated in one patient with silicoasbestosis.
authors.affiliation: Helsinki University of Technology, Helsinki University Hospital, Finland.
authors.forename: T
authors.initials: T
authors.lastname: Katila
authors.forename: P
authors.initials: P
authors.lastname: Piirilä
authors.forename: K
authors.initials: K
authors.lastname: Kallio
authors.forename: E
authors.initials: E
authors.lastname: Paajanen
authors.forename: T
authors.initials: T
authors.lastname: Rosqvist
authors.forename: A R
authors.initials: AR
authors.lastname: Sovijärvi
mesh_terms: D000162:Acoustics; D001195:Asbestosis / Q000503:physiopathology; D055592:Biophysical Phenomena; D001703:Biophysics; D006801:Humans; D008297:Male; D008875:Middle Aged; D015656:Respiratory Mechanics / Q000502:physiology; D012135:Respiratory Sounds / Q000503:physiopathology*; D012829:Silicosis / Q000503:physiopathology