Influence of surgical and N95 face masks on speech perception and listening effort in noise

Abstract

Daily-life conversation relies on speech perception in quiet and noise. Because of the COVID-19 pandemic, face masks have become mandatory in many situations. Acoustic attenuation of sound pressure by the mask tissue reduces speech perception ability, especially in noisy situations. Masks also can impede the process of speech comprehension by concealing the movements of the mouth, interfering with lip reading. In this prospective observational, cross-sectional study including 17 participants with normal hearing, we measured the influence of acoustic attenuation caused by medical face masks (mouth and nose protection) according to EN 14683 and of N95 masks according to EN 1149 (EN 14683) on the speech recognition threshold and listening effort in various types of background noise. Averaged over all noise signals, a surgical mask significantly reduced the speech perception threshold in noise was by 1.6 dB (95% confidence interval [CI], 1.0, 2.1) and an N95 mask reduced it significantly by 2.7 dB (95% CI, 2.2, 3.2). Use of a surgical mask did not significantly increase the 50% listening effort signal-to-noise ratio (increase of 0.58 dB; 95% CI, 0.4, 1.5), but use of an N95 mask did so significantly, by 2.2 dB (95% CI, 1.2, 3.1). In acoustic measures, mask tissue reduced amplitudes by up to 8 dB at frequencies above 1 kHz, whereas no reduction was observed below 1 kHz. We conclude that face masks reduce speech perception and increase listening effort in different noise signals. Together with additional interference because of impeded lip reading, the compound effect of face masks could have a relevant impact on daily life communication even in those with normal hearing.

Occlusion of lip movements impairs reconstruction of acoustic speech features and higher-level segmentational features in the presence of a distractor speaker

“…The effects of face masks on speech comprehension have been investigated in various studies on a behavioural level (Brown et al, 2021;Giovanelli et al, 2021;Rahne et al, 2021;Toscano & Toscano, 2021;Yi et al, 2021). Despite the overall agreement of adverse effects of face masks on speech comprehension, it has been unclear which features of speech processing are specifically affected.…”

Early Word Segmentation Behind the Mask

“…Such degradation can be mild ~2d B with a surgical mask and an FFP2 mask (Bottalico et al, 2020 ; Cruz et al, 2022 ) to more intense ~20 dB with transparent masks (Atcherson et al, 2020 ). Face masks, again depending on the material, affect other aspects of the acoustic signal, such as power distribution, spectral tilt, and timing, which are particularly affected by the FFP2 face mask (Rahne et al, 2021 ).…”

A Wide-bandwidth Nanocomposite-Sensor Integrated Smart Mask for Tracking Multi-phase Respiratory Activities for COVID-19 Endemic

“…The speech is produced by the vocal folds vibration induced air vibration when vocal folds come close as the air passing through during the exhalation of air from the lung [39]. Although a few research also suggest medical masks have no negative effect on speech understanding [40], more recent investigations have further demonstrated that both standard surgical masks and N95/KN95 respirators have an influence on the acoustic characteristics of voice [41-44], attenuating the mean spectral level by 2.0–5.2 dB in the high-frequency region from 1 to 8 kHz while not significantly affecting the low-frequency range from 0 to 1 kHz [41]. Additionally, the masks with higher barrier level have been proved to have greater attenuation of high-frequency components during the transmission of sound [41, 42], and masks impact more on human speech recognition in a higher level of background noise [45].…”

“…The speech is produced by the vocal folds vibration induced air vibration when vocal folds come close as the air passing through during the exhalation of air from the lung [39]. Although a few research also suggest medical masks have no negative effect on speech understanding [40], more recent investigations have further demonstrated that both standard surgical masks and N95/KN95 respirators have an influence on the acoustic characteristics of voice [41][42][43][44],…”