Limitations in the use of median frequency for lung sound analysis

Abstract

The aim of this paper is to investigate methods of standardizing lung sound analysis, with a view to supplementing traditional spirometric air flow measurements to help in the diagnosis of asthma and to provide a measure of the effectiveness of treatment. Lung sounds were measured in nine patients with asthma and five control subjects, alongside air flow measurements of forced expiratory volume (FEV₁) and forced vital capacity (FVC). The patients were administered the broncho-dilator, salbutamol, to assess how effective these measurement techniques were for quantifying its effect. The results agree with previous studies, that analysis of lung sounds is a potentially useful tool for indicating air flow changes. The results, however, also demonstrate that the emerging standard of ‘F₅₀’ or ‘median frequency’ should be treated with great caution because of its high sensitivity to the measurement frequency range. F₅₀ is very unlikely to provide a reliable single indicator of lung condition.

Keywords

asthma lung sounds frequency spectra median frequency

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References

Lung disease: A shadow over the nation's health. The Lung Report, British Lung Foundation, 1996.

Anderson

Aitken

Carter

Macleod

J. E.S.

Moran

Variation of breath sound and airway caliber induced by histamine challenge. Am. Rev. Respir. Dis., 1990, 141, 1147–1150.

Earis

Lung sounds. Thorax, 1992, 47, 671–672.

Gavriely

Analysis of breath sounds in bronchial provocation tests, Editorial. Am. J. Respir. Crit. Care Medicine, 1996, 153, 1469–1471.

Malmberg

L. P.

Sorva

Sovijarvi

A. R. A.

Frequency distribution of breath sounds as an indicator of bronchoconstriction during histamine challenge test in asthmatic children. Pediatr. Pulmonol., 1994, 18, 170–177.

Pasterkamp

Kraman

S. S.

Wodicka

Respiratory sounds—advances beyond the stethoscope. Am. J. Respir. Crit. Care Medicine, 1997, 156, 974–987.

Schruer

H. J. W.

Diamant

Vanderschoot

Zwinderman

A. H.

Dijkman

J. H.

Sterk

P. J.

Lung sounds during allergen-induced asthmatic responses in patients with asthma. Am. J. Respir. Crit. Care Medicine, 1996, 153, 1474–1480.

Ploysongsang

Iyer

V. K.

Rarnamoorthy

P. A.

Characteristics of normal lung sounds after adaptive filtering. Am. Rev. Respir. Dis., 1989, 139, 951–956.

Spence

D. P. S.

Bentley

S. S.

Evans

D. H.

Morgan

M. D. L.

Effect of methacholine induced bronchoconstriction on the spectral characteristics of breath sounds in asthma. Thorax, 1992, 47, 680–683.

10.

Malmberg

L. P.

Pesu

Sovijarvi

A. R. A.

Significant differences in flow standardised breath sound spectra in patients with chronic obstructive pulmonary disease, stable asthma, and healthy lungs. Thorax, 1995, 50, 1285–1291.

11.

Malmberg

L. P.

Sovijarvi

A. R. A.

Paajanen

Piirila

Haahtela

Katila

Changes in frequency spectra of breath sounds during histamine challenge test in adult asthmatics and healthy control subjects. Chest, 1994, 105 (1), 122–131.

12.

Charbonneau

Racineux

J. L.

Sudraud

Tuchais

An accurate recording system and its use in breath sounds spectral analysis. J. Appl. Physiol., 1983, 55, 1120–1127.

13.

Gavriely

Palti

Alroy

Grotberg

J. B.

Measurement and theory of wheezing breath sounds. J. Appl. Physiol., 1984, 57, 481–492.

14.

Pasterkamp

Fenton

Tal

Chernick

Interference of cardiovascular sounds with phononeumography in children. Am. Rev. Respir. Dis., 1985, 131, 61–64.

15.

Shykoff

B. E.

Ploysongsang

Chang

H. K.

Airflow and normal lung sounds. Am. Rev. Respir. Dis., 1988, 137, 872–876.

16.

Beck

Dickson

Montgomery

M. D.

Mitchell

Histamine challenge in young children using computerised lung sounds analysis. Chest, 1992, 103 (3), 759–763.

17.

Bohadana

A. B.

Peslin

Uffholtz

Pauli

Potential for lung sound monitoring during bronchial provocation testing. Thorax, 1995, 50, 955–961.

18.

Schreur

H. J. W.

Sterk

P. J.

Vanderschoot

van Klink

H. C. J.

van Vollenhoven

Dijkman

J. H.

Lung sound intensity in patients with emphysema and in normal subjects at standardised airflows. Thorax, 1992, 47, 674–679.

19.

Gavriely

Nissan

Rubin

A.-H. E.

Cugell

D. W.

Spectral characteristics of chest wall breath sounds in normal subjects. Thorax, 1995, 50, 1292–1300.

20.

Packer

Carter

Whittaker

A. R.

Lucas

Thomson

N. C.

Anderson

Bronchodilator effects on breath sound frequency in asthma. Thorax, 1997, 12, 190.

21.

Pasterkamp

Powell

Sanchez

Lung sound spectra at standardized air flow in normal infants, children, and adults. Am. J. Respir. Crit. Care Medicine, 1996, 154, 424–430.

22.

Pasterkamp

Kraman

S. S.

DeFrain

P. D.

Wodicka

G. R.

Measurement of respiratory acoustical signals. Chest, 1993, 104 (5), 1518–1525.

23.

MATLAB Reference Guide, 1992 (MathWorks Inc., Massachusetts).

24.

Respiratory Acoustics Laboratory Environment. Web Site: http://www.rale.ca/