Abstract
Daily life conversation relies on speech perception in quiet and noise. Due to the COVID-19 pandemic, the usage of face masks has become mandatory in many situations. Acoustic attenuation of sound pressure by the mask tissue reduces speech perception ability especially in noisy situations. Mask also impede the process of speech information from sight of the moving mouth (lip reading).
In a prospective exploratory experimental study including 17 normal hearing participants, speech perception in noise and listening effort were measured with and without a surgical mask or an N95 mask between the speech signal and the listener. Additionally, the influence of the masks on the acoustic frequency spectrum was measured.
Averaged over all noise signals, speech perception threshold in noise was significantly reduced by 1.6 dB (95% CI[1.0, 2.1]) by a surgical mask and by 2.7 dB (95% CI[2.2, 3.2]) using an N95 mask. The 50%-listening effort signal-to-noise ratio was not significantly increased by 0.58 dB (95% CI[0.4, 1.5]) by a surgical mask but significantly increased by 2.2 dB (95% CI[1.2, 3.1]) using an N95 mask. In acoustic measures the amplitudes were reduced by the mask tissue by up to 8 dB at frequencies above 1 kHz while 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 an additional interference by missing lip reading the compound effect of face masks would have a relevant impact on daily life communication already in normal hearing subjects.