How Face Masks Interfere With Speech Understanding of Normal-Hearing Individuals: Vision Makes the Difference.

OBJECTIVE: To investigate the effects of wearing a simulated mask on speech perception of normal-hearing subjects. STUDY DESIGN: Prospective cohort study. SETTING: University hospital. PATIENTS: Fifteen normal-hearing, native German speakers (8 female, 7 male). INTERVENTION: Different experimental conditions with and without simulated face masks using the audiovisual version of the female German Matrix test (Oldenburger Satztest, OLSA). MAIN OUTCOME MEASURES: Signal-to-noise ratio (SNR) at speech intelligibility of 80%. RESULTS: The SNR at which 80% speech intelligibility was achieved deteriorated by a mean of 4.1 dB SNR when simulating a medical mask and by 5.1 dB SNR when simulating a cloth mask in comparison to the audiovisual condition without mask. Interestingly, the contribution of the visual component alone was 2.6 dB SNR and thus had a larger effect than the acoustic component in the medical mask condition. CONCLUSIONS: As expected, speech understanding with face masks was significantly worse than under control conditions. Thus, the speaker's use of face masks leads to a significant deterioration of speech understanding by the normal-hearing listener. The data suggest that these effects may play a role in many everyday situations that typically involve noise.