Acoustic analysis of the effect of personal protective equipment on speech understanding: lessons for clinical environments

Abstract

Objective

The use of various types of filtering facepiece class 3 (FFP3) mask have become commonplace since the Covid-19 outbreak. These have been evaluated in terms of efficacy regarding aerosol filtration but less emphasis has been placed on the acoustic effects of such masks and their consequences for clinical communication.

Design

A microphone 65 cm from a sound-producing Head and Torso Simulator (wearing the masks) was used to measure attenuation via a tone sweep. Predicted impact on speech reception in noise was assessed by weighting the attenuations of cochlear excitation patterns by the frequency importance function of the Speech Intelligibility Index.

Study sample

We evaluated acoustic attenuation properties of seven FFP3 masks and a Type IIR surgical mask (as a comparator).

Results

The Type IIR mask had the smallest impact on SNR (2.6 dB with visor). Most FFP3s with an addition of a visor (if not already face covering) impacted SNR by approximately 6 dB. The 3 M 6000 was significantly worse (15.8 dB).

Conclusions

Mouth-and-nose covering FFP3s masks had similar effects on SNR (≈6.2 dB with visor). The Tecmen TM-H2 had several advantages over other masks evaluated. It was reusable, allowed lipreading clues and the attenuation was similar to other FFP3s.

Keywords:

• Covid-19
• mask
• personal protective equipment
• communication

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

Data are available upon reasonable request.

Additional information

Funding

The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.