Effects of Medical Masks on Voice Assessment During the COVID-19 Pandemic

Abstract

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.

Does the wearing of masks change voice and speech parameters?

“…The harmonics-to-noise ratio (HNR) values were significantly increased with the wearing of a mask, either a surgical or a KN95, when compared to the no-mask condition [8,13]; it was also increased after a mask-wearing workday comparing with the pre-workday value [11]. However, cepstral peak prominence (CPP) showed none or minimally changes with mask-wearing in all studies [5,7,8,13].…”

“…A total of 1005 people were assessed for voice changes. Of the nine selected articles, six [5,7,8,10,11,13] outlined acoustic parameters, four [6,9,11,12] described self-reported vocal characteristics, and only two [8,10] assessed voice aerodynamics. None of them described all three vocal domains, neither perceptual voice evaluation.…”

“…Fundamental frequency (F0) values did not seem to be significantly changed by the wearing of a mask [5,7,8,10], although a significant decrease in relative fundamental frequency (RFF) offset ten was observed in mask wearers after a workday (p = 0,001), especially when wearing KN95 [11].…”

“…Overall, when comparing mask and no-mask scenarios (regardless of the type of mask), it was observed a significant increase in vocal intensity while wearing a face mask in all [5,7,8,11] but two of the six studies performing acoustic voice evaluation [10,13].…”

“…Some studies also measured formants frequency F1, F2 and F3 [5,8]. Formant frequency F2 showed to be altered in Joshi et al [5] decreasing in males with KSF scenario (face shield over surgical mask and KN95), and increased in females wearing a surgical mask when comparing with other mask-type scenarios.…”