Challenging Times for Cochlear Implant Users - Effect of Face Masks on Audiovisual Speech Understanding during the COVID-19 Pandemic.

Unhindered auditory and visual signals are essential for a sufficient speech understanding of cochlear implant (CI) users. Face masks are an important hygiene measurement against the COVID-19 virus but disrupt these signals. This study determinates the extent and the mechanisms of speech intelligibility alteration in CI users caused by different face masks. The audiovisual German matrix sentence test was used to determine speech reception thresholds (SRT) in noise in different conditions (audiovisual, audio-only, speechreading and masked audiovisual using two different face masks). Thirty-seven CI users and ten normal-hearing listeners (NH) were included. CI users showed a reduction in speech reception threshold of 5.0 dB due to surgical mask and 6.5 dB due to FFP2 mask compared to the audiovisual condition without mask. The greater proportion of reduction in SRT by mask could be accounted for by the loss of the visual signal (up to 4.5 dB). The effect of each mask was significantly larger in CI users who exclusively hear with their CI (surgical: 7.8 dB, p = 0.005 and FFP2: 8.7 dB, p = 0.01) compared to NH (surgical: 3.8 dB and FFP2: 5.1 dB). This study confirms that CI users who exclusively rely on their CI for hearing are particularly susceptible. Therefore, visual signals should be made accessible for communication whenever possible, especially when communicating with CI users.

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.