Does the wearing of masks change voice and speech parameters?

Masks and respirators for prevention of respiratory infections: a state of the science review

SUMMARYThis narrative review and meta-analysis summarizes a broad evidence base on the benefits-and also the practicalities, disbenefits, harms and personal, sociocultural and environmental impacts-of masks and masking. Our synthesis of evidence from over 100 published reviews and selected primary studies, including re-analyzing contested meta-analyses of key clinical trials, produced seven key findings. First, there is strong and consistent evidence for airborne transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other respiratory pathogens. Second, masks are, if correctly and consistently worn, effective in reducing transmission of respiratory diseases and show a dose-response effect. Third, respirators are significantly more effective than medical or cloth masks. Fourth, mask mandates are, overall, effective in reducing community transmission of respiratory pathogens. Fifth, masks are important sociocultural symbols; non-adherence to masking is sometimes linked to political and ideological beliefs and to widely circulated mis- or disinformation. Sixth, while there is much evidence that masks are not generally harmful to the general population, masking may be relatively contraindicated in individuals with certain medical conditions, who may require exemption. Furthermore, certain groups (notably D/deaf people) are disadvantaged when others are masked. Finally, there are risks to the environment from single-use masks and respirators. We propose an agenda for future research, including improved characterization of the situations in which masking should be recommended or mandated; attention to comfort and acceptability; generalized and disability-focused communication support in settings where masks are worn; and development and testing of novel materials and designs for improved filtration, breathability, and environmental impact.

Factors influencing speech improvement following maxillary complete-arch implant-supported restorations: A retrospective study

OBJECTIVE

This study explored factors affecting speech improvement in patients with an edentulous maxilla after the delivery of a complete-arch implant-supported fixed dental prosthesis (IFDP).

MATERIALS AND METHODS

Patients who had received IFDP for edentulous maxilla were enrolled, and various potential speech improvement-related factors were considered, including patient demographics, anterior residual bone volume, preoperative facial features, preoperative acoustic parameters, and adaptation time. Acoustic analysis and perceptual ratings were used to assess three fricatives [s], [f], and [ɕ]. Correlation and regression analyses were conducted to assess the association between changes in fricatives and potential factors (α = .05).

RESULTS

The study included 50 patients (18 females and 32 males, aged 50.62 ± 15.71 years, range 19-76). Significant correlations were found among the change in the center of gravity (ΔCoG) of [s] and anterior residual bone volume, zygomatic implants number and proportion (p < .05). These correlations were largely mirrored in the perceptual score (ΔPS) changes. After controlling for age, sex, preoperative acoustic parameters, and adaptation time, the ΔCoG and ΔPS of fricatives were mainly correlated with the anterior residual bone volume, preoperative acoustic parameters, and adaptation time.

CONCLUSION

Speech improvements post-IFDP delivery are mainly related to preoperative speech characteristics, anterior residual bone volume, and adaptation time. The residual bone volume's impact on consonants varies with specific articulatory gestures. This study provides insights into forecasting speech outcomes following IFDP restoration and provides recommendations and methods for data collection in developing future prediction models.

A positive side effect of wearing face coverings for socially anxious females: Findings from a speech task

Background

Wearing face masks has become more common due to the COVID-19 pandemic. Until now, it has not been investigated whether socially anxious individuals can reduce their acute anxiety symptoms by wearing face masks during a speech task.

Method

Fifty-nine socially anxious females were asked to prepare and give an oral presentation. Participants were randomly allocated either to a group that was asked to wear a face mask during the task, or to a group that was not asked to wear a face mask during the task. Dependent variables included physiological parameters (systolic/diastolic blood pressure, heart rate) and self-reports (valence and arousal at baseline, as well as directly before and after the presentation).

Results

The analyses showed that the group without face masks had a higher systolic blood pressure than the group with face masks, directly before as well as after the presentation. The two groups did not differ in the other measures.

Conclusion

Wearing face masks has a small stress-reducing effect on socially anxious females.

Association Between Vocal Symptoms, Communication, Work Environment, and Sense of Coherence in Hospital Health Professionals

OBJECTIVE

This study aimed to associate the presence of vocal symptoms with sociodemographic and occupational data, work environment self-perception, oral communication wearing a face mask, and the sense of coherence (SOC).

METHOD

This cross-sectional analytical observational study included 66 health professionals from a Brazilian hospital. They answered an online questionnaire on sociodemographic aspects, self-perception of the physical work environment, and oral communication at work. The Voice Symptom Scale (VoiSS) and Sense of Coherence Scale (SOC-13) were also applied. The significance level was set at 5% for the statistical analysis.

RESULTS

The self-perception of vocal symptoms was 62%. Professionals who considered the noise in their work environment unsatisfactory had more vocal symptoms (P = 0.005), especially in the limitation (P = 0.013) and physical (P = 0.028) domains of the VoiSS. Professionals with higher self-perceived vocal symptoms also reported incoordination between breathing, speech, and articulation (P = 0.041) and self-perceived difficulty being heard with a protective mask (P = 0.033). Professionals with a higher self-perceived score in the limitation domain of the VoiSS also had a higher self-perceived effort to speak with a mask (P = 0.035) and a higher self-perception that other people find it difficult to hear them with a face mask (P = 0.050). There was a weak negative correlation between VoiSS and SOC (P < 0.05) and between its domains (P < 0.05).

CONCLUSION

Self-perception of voice symptoms is high among health professionals in a Brazilian public hospital. The presence of these symptoms is related to the perception of a noisy work environment and communication difficulties due to the use of a face mask. The lower the ability to cope with stressful situations, the larger the presence of voice symptoms among health professionals.

Influence of face masks on recalibration of phonetic categories

Previous research demonstrates listeners dynamically adjust phonetic categories in line with lexical context. While listeners show flexibility in adapting speech categories, recalibration may be constrained when variability can be attributed externally. It has been hypothesized that when listeners attribute atypical speech input to a causal factor, phonetic recalibration is attenuated. The current study investigated this theory directly by examining the influence of face masks, an external factor that affects both visual and articulatory cues, on the magnitude of phonetic recalibration. Across four experiments, listeners completed a lexical decision exposure phase in which they heard an ambiguous sound in either /s/-biasing or /ʃ/-biasing lexical contexts, while simultaneously viewing a speaker with a mask off, mask on the chin, or mask over the mouth. Following exposure, all listeners completed an auditory phonetic categorization test along an /ʃ/-/s/ continuum. In Experiment 1 (when no face mask was present during exposure trials), Experiment 2 (when the face mask was on the chin), Experiment 3 (when the face mask was on the mouth during ambiguous items), and Experiment 4 (when the face mask was on the mouth during the entire exposure phase), listeners showed a robust and equivalent phonetic recalibration effect. Recalibration manifested as greater proportion /s/ responses for listeners in the /s/-biased exposure group, relative to listeners in the /ʃ/-biased exposure group. Results support the notion that listeners do not causally attribute face masks with speech idiosyncrasies, which may reflect a general speech learning adjustment during the COVID-19 pandemic.

Effects of Personal Protective Equipment on Speech Acoustics

Objectives

The transmission of severe acute respiratory syndrome coronavirus-2 occurs primarily through droplets, which highlights the importance of protecting the oral, nasal, and conjunctival mucosas using personal protective equipment (PPE). The use of PPE can lead to communication difficulties between healthcare workers and patients. This study aimed to investigate changes in the acoustic parameters of speech sounds when different types of PPE are used.

Methods

A cross-sectional study was conducted, enrolling 18 healthy male and female participants. They were instructed to produce a sustained [ɑː] vowel for at least 3 s to estimate voice quality. In addition, all Turkish vowels were produced for a minimum of 200 ms. Finally, three Turkish fricative consonants ([f], [s], and [ʃ]) were produced in a consonant/vowel/consonant format with different vowel contexts within a carrier sentence. Recordings were repeated under the following conditions: no PPE, surgical mask, N99 mask, face shield, surgical mask + face shield, and N99 mask + face shield. All recordings were subjected to analysis.

Results

Frequency perturbation parameters did not show significant differences. However, in males, all vowels except [u] in the first formant (F1), except [ɔ] and [u] in the second formant (F2), except [ɛ] and [ɔ] in the third formant (F3), and only [i] in the fourth formant (F4) were significant. In females, all vowels except [i] in F1, except [u] in F2, all vowels in F3, and except [u] and [ɯ] in F4 were significant. Spectral moment values exhibited significance in both groups.

Conclusion

The use of different types of PPE resulted in variations in speech acoustic features. These findings may be attributed to the filtering effects of PPE on specific frequencies and the potential chamber effect in front of the face. Understanding the impact of PPE on speech acoustics contributes to addressing communication challenges in healthcare settings.

The Impact of Protective Face Coverings on Acoustic Markers in Voice: A Systematic Review and Meta-Analysis

BACKGROUND

Wearing respiratory protective masks (RPMs) has become common worldwide, especially in healthcare settings, since the onset of the COVID-19 pandemic. Hypotheses have suggested that sound transmission could be limited by RPMs, which possibly affects the characteristics of acoustic energy and speech intelligibility. The objective of this study was to investigate the effect of RPMs on acoustic measurements through a systematic review with meta-analysis.

METHODS

Five database searches were conducted, ranging from their inception to August 2023, as well as a manual search. Cross-sectional studies were included that provided data on widely used gender-independent clinical acoustic voice quality measures (jitter, shimmer, HNR, CPPS, and AVQI) and habitual sound pressure level (SPL).

RESULTS

We found nine eligible research studies with a total of 422 participants who were compared both without masks and with different types of masks. All included studies focused on individuals with vocally healthy voices, while two of the studies also included those with voice disorders. The results from the meta-analysis were related to medical/surgical and FFP2/(K)N95 masks. None of the acoustic measurements showed significant differences between the absence and presence of masks (p > 0.05). When indirectly comparing both mask types, statistical significance was identified for parameters of jitter, HNR, CPPS and SPL (p < 0.001).

CONCLUSIONS

The present meta-analysis indicates that certain types of RPMs have no significant influence on common voice quality parameters and SPL compared to recordings without masks. Nevertheless, it is plausible that significant differences in acoustic parameters might exist between different mask types. Consequently, it is advisable for the clinical practice to always use the same mask type when using RPMs to ensure high comparability and accuracy of measurement results.

Effect of Wearing Different Masks on Acoustic, Aerodynamic, and Formant Parameters

OBJECTIVE

This study aimed to investigate the effects of different types of masks on acoustic, aerodynamic, and formant parameters in healthy people.

METHODS

Our study involved 30 healthy participants, 15 of each gender, aged 20-40 years. The tests were conducted under four conditions: without a mask, after wearing a surgical mask, after wearing a head-mounted N95 mask, and after wearing an ear-mounted N95 mask. Voice recording was done with the mask on. The acoustic parameters include mean fundamental frequency (F0), mean intensity, percentage of jitter (local), percentage of shimmer (local), mean noise to harmonic ratio (NHR), aerodynamic parameter, maximum phonation time (MPT), and formant parameters (/a/, /i/, /u/ three vowels F1, F2).

RESULTS

The main effect of mask type was significant in MPT, mean F0, mean HNR, /a/F1, /a/F2, /i/F2. However, the effect sizes and power in /a/F2, /i/F2 were low. MPT, mean F0 and mean HNR significantly increased and /a/F1 significantly decreased after wearing the head-mounted n95 mask. The mean F0 and mean HNR increased significantly after wearing the ear-mounted n95 mask. No significant changes were observed in parameters after wearing the surgical mask in this study. When the statistics are performed separately for males and females, the results obtained are similar to those previously obtained for unspecified males and females.

CONCLUSION

After wearing the surgical mask, this study found insignificant changes in mean F0, jitter (local), shimmer (local), mean NHR, mean intensity, MPT, and the vowels F1 and F2. This may be due to the looser design of the surgical mask and the relatively small attenuation of sound. N95 masks have a greater effect on vocalization than surgical masks and may cause changes in F0 and HNR after wearing an N95 mask. In the present study, no significant changes in jitter and shimmer were observed after wearing the mask. In addition, there was a significant reduction in /a/F1 after wearing the N95 headgear mask may owing to its high restriction of jaw mobility. In future studies, the change in jaw movement amplitude after wearing the mouthpiece can be added to investigate.

Speaking with mask in the COVID-19 era: Multiclass machine learning classification of acoustic and perceptual parameters

The intensive use of personal protective equipment often requires increasing voice intensity, with possible development of voice disorders. This paper exploits machine learning approaches to investigate the impact of different types of masks on sustained vowels /a/, /i/, and /u/ and the sequence /a'jw/ inside a standardized sentence. Both objective acoustical parameters and subjective ratings were used for statistical analysis, multiple comparisons, and in multivariate machine learning classification experiments. Significant differences were found between mask+shield configuration and no-mask and between mask and mask+shield conditions. Power spectral density decreases with statistical significance above 1.5 kHz when wearing masks. Subjective ratings confirmed increasing discomfort from no-mask condition to protective masks and shield. Machine learning techniques proved that masks alter voice production: in a multiclass experiment, random forest (RF) models were able to distinguish amongst seven masks conditions with up to 94% validation accuracy, separating masked from unmasked conditions with up to 100% validation accuracy and detecting the shield presence with up to 86% validation accuracy. Moreover, an RF classifier allowed distinguishing male from female subject in masked conditions with 100% validation accuracy. Combining acoustic and perceptual analysis represents a robust approach to characterize masks configurations and quantify the corresponding level of discomfort.

Effects of Wearing FFP2 Masks on SARS-CoV-2 Infection Rates in Classrooms

In this retrospective cohort study involving 614 secondary school students, the likelihood of becoming infected with SARS-CoV-2 in schools with different focus (sports focus vs. general branch; the only difference in the sports focus school was that PE was allowed at all times without restrictions) and different prevailing restrictions were compared. A significantly higher likelihood of infection with SARS-CoV-2 was found in sports classes during the period with a strict FFP-2 mask requirement compared to general branch classes (for Delta from November 2021 to December 2021, and for Omicron from January 2022 to February 2022). The higher likelihood of infection was observed both during the Delta and the Omicron wave. After the relaxation of the mitigation measures, however, students in general branch classes showed a clear "catch-up" of infections, leading to a higher incidence of infections during this phase. By the end of the observation period (30 April 2022), only a small difference in cumulative SARS-CoV-2 infection rates (p = 0.037, φ = 0.09) was detected between classes with a sports focus and those without a sports focus. The results suggest that SARS-CoV-2 transmission can be reduced in school classes by mandatory FFP-2 mask use. In many cases, however, infection appears to be postponed rather than avoided.

COVID-19 masks: A barrier to facial and vocal information

With the COVID-19 pandemic, we have become used to wearing masks and have experienced how masks seem to impair emotion and speech recognition. While several studies have focused on facial emotion recognition by adding images of masks on photographs of emotional faces, we have created a video database with actors really wearing masks to test its effect in more ecological conditions. After validating the emotions displayed by the actors, we found that surgical mask impaired happiness and sadness recognition but not neutrality. Moreover, for happiness, this effect was specific to the mask and not to covering the lower part of the face, possibly due to a cognitive bias associated with the surgical mask. We also created videos with speech and tested the effect of mask on emotion and speech recognition when displayed in auditory, visual, or audiovisual modalities. In visual and audiovisual modalities, mask impaired happiness and sadness but improved neutrality recognition. Mask impaired the recognition of bilabial syllables regardless of modality. In addition, it altered speech recognition only in the audiovisual modality for participants above 70 years old. Overall, COVID-19 masks mainly impair emotion recognition, except for older participants for whom it also impacts speech recognition, probably because they rely more on visual information to compensate age-related hearing loss.

A rapid, non-invasive method for fatigue detection based on voice information

Fatigue results from a series of physiological and psychological changes due to continuous energy consumption. It can affect the physiological states of operators, thereby reducing their labor capacity. Fatigue can also reduce efficiency and, in serious cases, cause severe accidents. In addition, it can trigger pathological-related changes. By establishing appropriate methods to closely monitor the fatigue status of personnel and relieve the fatigue on time, operation-related injuries can be reduced. Existing fatigue detection methods mostly include subjective methods, such as fatigue scales, or those involving the use of professional instruments, which are more demanding for operators and cannot detect fatigue levels in real time. Speech contains information that can be used as acoustic biomarkers to monitor physiological and psychological statuses. In this study, we constructed a fatigue model based on the method of sleep deprivation by collecting various physiological indexes, such as P300 and glucocorticoid level in saliva, as well as fatigue questionnaires filled by 15 participants under different fatigue procedures and graded the fatigue levels accordingly. We then extracted the speech features at different instances and constructed a model to match the speech features and the degree of fatigue using a machine learning algorithm. Thus, we established a method to rapidly judge the degree of fatigue based on speech. The accuracy of the judgment based on unitary voice could reach 94%, whereas that based on long speech could reach 81%. Our fatigue detection method based on acoustic information can easily and rapidly determine the fatigue levels of the participants. This method can operate in real time and is non-invasive and efficient. Moreover, it can be combined with the advantages of information technology and big data to expand its applicability.

Speech air flow with and without face masks

Face masks slow exhaled air flow and sequester exhaled particles. There are many types of face masks on the market today, each having widely varying fits, filtering, and air redirection characteristics. While particle filtration and flow resistance from masks has been well studied, their effects on speech air flow has not. We built a schlieren system and recorded speech air flow with 14 different face masks, comparing it to mask-less speech. All of the face masks reduced air flow from speech, but some allowed air flow features to reach further than 40 cm from a speaker's lips and nose within a few seconds, and all the face masks allowed some air to escape above the nose. Evidence from available literature shows that distancing and ventilation in higher-risk indoor environment provide more benefit than wearing a face mask. Our own research shows all the masks we tested provide some additional benefit of restricting air flow from a speaker. However, well-fitted mask specifically designed for the purpose of preventing the spread of disease reduce air flow the most. Future research will study the effects of face masks on speech communication in order to facilitate cost/benefit analysis of mask usage in various environments.