Effect of face masks on speech perception in noise of individuals with hearing aids

Although several previous studies have confirmed that listeners find it difficult to perceive the speech of face-mask-wearing speakers, there has been little research into how masks affect hearing-impaired individuals using hearing aids. Therefore, the aim of this study was to compare the effects of masks on the speech perception in noise of hearing-impaired individuals and normal-hearing individuals. We also investigated the effect of masks on the gain conferred by hearing aids. The hearing-impaired group included 24 listeners (age: M = 69.5, SD = 8.6; M:F = 13:11) who had used hearing aids in everyday life for >1 month (M = 20.7, SD = 24.0) and the normal-hearing group included 26 listeners (age: M = 57.9, SD = 11.1; M:F = 13:13). Speech perception in noise was measured under no mask-auditory-only (no-mask-AO), no mask-auditory-visual (no-mask-AV), and mask-AV conditions at five signal-to-noise ratios (SNRs; -16, -12, -8, -4, 0 dB) using five lists of 25 monosyllabic Korean words. Video clips that included a female speaker's face and sound or the sound only were presented through a monitor and a loudspeaker located 1 m in front of the listener in a sound-attenuating booth. The degree of deterioration in speech perception caused by the mask (no-mask-AV minus mask-AV) was significantly greater for hearing-impaired vs. normal-hearing participants only at 0 dB SNR (Bonferroni's corrected p < 0.01). When the effects of a mask on speech perception, with and without hearing aids, were compared in the hearing-impaired group, the degree of deterioration in speech perception caused by the mask was significantly reduced by the hearing aids compared with that without hearing aids at 0 and -4 dB SNR (Bonferroni's corrected p < 0.01). The improvement conferred by hearing aids (unaided speech perception score minus aided speech perception score) was significantly greater at 0 and -4 dB SNR than at -16 dB SNR in the mask-AV group (Bonferroni's corrected p < 0.01). These results demonstrate that hearing aids still improve speech perception when the speaker is masked, and that hearing aids partly offset the effect of a mask at relatively low noise levels.