Objective. Voice assessment is of great significance to the evaluation of voice quality. Our study aims to explore the effects of medical masks on healthy people in acoustic, aerodynamic and formant parameters during the COVID-19 pandemic. In addition, we also attempted to verify the differences between different sexes and ages. Methods. Fifty-three healthy participants (25 males and 28 females) were involved in our study. The acoustic parameters, including fundamental frequency (F0), sound pressure level (SPL), percentage of jitter (%), percentage of shimmer (%), noise to harmonic ratio (NHR) and cepstral peak prominence (CPP), aerodynamic parameter (maximum phonation time, MPT) and formant parameters (formant frequency, F1, F2, F3) without and with wearing medical masks were included. We further investigated the potential differences in the impact on different sexes and ages (≤45 years old and >45 years old). Results. While wearing medical masks, the SPL significantly increased (71.22 §4.25 dB, 72.42 §3.96 dB, P = 0.021). Jitter and shimmer significantly decreased (jitter 1.19 §0.83, 0.87 §0.67 P = 0.005; shimmer 4.49 § 2.20, 3.66 §2.02 P = 0.002), as did F3 (2855 §323.34 Hz, 2781.89 §353.42 Hz P = 0.004). F0, MPT, F1 and F2 showed increasing trends without statistical significance, and NHR as well as CPP showed little change without and with wearing medical masks. There were no significant differences seen between males and females. Regarding to age, a significant difference in MPT was seen (>45-year-old 16.15 §6.98 s, 15.38 §7.02 s; ≤45-year-old 20.26 §6.47 s, 21.44 §6.98 s, P = 0.032). Conclusion. Healthy participants showed a significantly higher SPL, a smaller perturbation and an evident decrease in F3 after wearing medical masks. These changes may result from the adjustment of the vocal tract and the filtration function of medical masks, leading to the stability of voices we recorded being overstated. The impacts of medical masks on sex were not evident, while the MPT in the >45-year-old group was influenced more than that in the ≤45-year-old group.

We demonstrate that acoustic subwavelength imaging can be realized through the spoof surface acoustic waves on the surface phononic crystal which is composed of borehole arrays with square lattice in a rigid plate. The dispersion property of the spoof surface acoustic waves on the two-dimensional textured rigid plate is analyzed theoretically. By utilizing the broad flat equifrequency contour of the spoof surface acoustic waves, a subwavelength image with full width at half maximum of 0.14 λ has been obtained both numerically and experimentally. We believe that such work can bring potential applications in the design of acoustic imaging and focusing devices.

Purpose: The purpose of this study was to explore the effects of medical masks on the voice quality of patients with voice disorders. Method: We included 106 patients diagnosed with voice disorders. Among them, 59 were diagnosed with vocal-fold benign lesions, 27 with insufficient glottis closure, and 20 with precancerous lesions/early-stage glottic carcinoma. Perceptual parameters (GRBAS [grade, roughness, breathiness, asthenia, strain] scale), acoustic parameters ( f o , sound pressure level [SPL], jitter, shimmer, noise-to-harmonic ratio [NHR], and cepstral peak prominence [CPP]), and maximum phonation time (MPT) without and with medical masks were analyzed. Changes in the GRBAS scale after wearing medical masks were also evaluated. Results: With medical mask wearing, the G, R, and B scales in the vocal-fold benign lesion and insufficient glottic closure groups decreased, with a statistical significance seen in the G and R scales of the vocal-fold benign lesion group (G 1.07 ± 0.59, 0.95 ± 0.68, p < .01; R 1.07 ± 0.59, 0.95 ± 0.68, p < .01). The B scale in the precancerous lesions/early-stage glottic carcinoma (95%) and vocal-fold benign lesion groups (83%) and R scale in the insufficient glottic closure group (77.8%) were stable with mask wearing. f o and SPL in the vocal-fold benign lesion group and f o and jitter in the insufficient glottic closure group increased significantly with medical masks. The NHR and CPP in each group changed little, and all the parameters in the precancerous lesions/early-stage glottic carcinoma group showed no significant change. Conclusions: The effects of medical masks on the voice quality of patients with voice disorders were associated with the type of the disease, degree of hoarseness, and subjective scale influencing specific voice disorder. When wearing medical masks, the pitch and loudness of patients increased as compensation. Medical masks had the least impact on the precancerous lesions/early-stage glottic carcinoma group.