Sound differences between electronic and acoustic stethoscopes

Lukasz J Nowak,Karolina M Nowak

doi:10.1186/s12938-018-0540-2

Abstract

BackgroundThe area of application of electronic stethoscopes in medical diagnostics covers the scope of usability of the acoustic stethoscopes, from which they have evolved and which they could potentially replace. However, the principle of operation of these two groups of diagnostic devices is substantially different. Thus, an important question arises, regarding the differences in parameters of the transmitted sound and their potential diagnostic consequences in clinical practice.MethodsIn order to answer this question, heart auscultation signals are recorded using various stethoscopes and divided into short fragments based on the analysis of the synchronized recordings of electrocardiogram signals. Next, a dedicated algorithm is used to extract representative datasets for each case, which are then analyzed for their acoustic parameters. Four different electronic stethoscopes were investigated, together with an acoustic stethoscope as a reference point.ResultsThe determined acoustic characteristics of the considered stethoscopes differ significantly between each other.ConclusionsThe differences in sound transmitted by various stethoscope models may translate into significant differences in quality of the obtained diagnosis. It is also pointed out, that the terminology and application guidelines regarding the electronic stethoscopes are misleading and should be changed.

Highlights

The area of application of electronic stethoscopes in medical diagnos‐ tics covers the scope of usability of the acoustic stethoscopes, from which they have evolved and which they could potentially replace
In order to better expose the difference in acoustic characteristics of the stethoscopes operating in bell and diaphragm modes, a bell-to-diaphragm coefficient, defined as: ABD f was computed for each of the investigated diagnostic devices
The comparison between the obtained data clearly shows, that parameters of sound transmitted through various investigated models of electronic stethoscopes differ significantly both between each other and between the parameters of sound transmitted through the acoustic stethoscope

Summary

Introduction

The area of application of electronic stethoscopes in medical diagnos‐ tics covers the scope of usability of the acoustic stethoscopes, from which they have evolved and which they could potentially replace. An important question arises, regarding the differences in parameters of the transmitted sound and their potential diagnostic consequences in clinical practice. Conclusions: The differences in sound transmitted by various stethoscope models may translate into significant differences in quality of the obtained diagnosis. It is pointed out, that the terminology and application guidelines regarding the electronic stethoscopes are misleading and should be changed. Acoustic stethoscopes, invented over two centuries ago, are the most commonly used medical diagnostic devices and the symbol of healthcare professionals. The role of the diaphragm of a chestpiece in filtering low-frequency signal components, as described in the literature, is questioned in the light of the new findings [8, 9]

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