Chart 2. Characteristics of studies that assessed effects on voice quality and speech acoustics included in the integrative review.
| Title | Country/year | Design/number of patients | Intervention | Outcome | Level of Evidence |
|---|---|---|---|---|---|
| Voice Differences When Wearing and Not Wearing a Surgical Mask(20) | Italy, 2021 |
Longitudinal, case-control study n= 60 |
With intervention of mask use. | Mask use can induce an unconscious need to increase vocal effort, resulting in a greater risk of developing functional dysphonia. | IV |
| Voice Acoustics and Vocal Effort in Mask-Wearing Healthcare Professionals: A Comparison Preand Post-Workday(21) | USA, 2021 |
Cross-sectional study. n=18 |
No intervention | Health professionals who use masks reported greater vocal symptoms after working hours compared to pre-workdays. | IV |
| The Effects of the Use of Protective Face Mask on the Voice and Its Relation to Self-Perceived Voice Changes(22) |
Greece, 2021 | Cross-sectional, observational study n=155 |
No intervention | Protective face mask use may result in the onset of a voice disorder, particularly in the high-risk population. | IV |
| The Effect of Masks and Respirators on Acoustic Voice Analysis During the COVID-19 Pandemic(23) | Turkey, 2021 | Prospective study n=204 |
With intervention of mask use. | Significant difference only in the Shimmer and HNR values in relation to the other analysis values. | IV |
| Self-Perceived Voice Handicap During COVID19 Compulsory Facemask Use: A Comparative Study Between Portuguese and Spanish Speakers(24) |
Spain, 2021 | Comparative observational descriptive study n = 558 |
With intervention of mask use. | Overall VHI scores and all-dimension scores were higher for the masked condition. | IV |
| Effects of Medical Masks on Voice Assessment During the COVID-19 Pandemic(25) |
China, 2021 | Cross-sectional study n=53 |
With intervention of mask use. | Healthy participants showed a significantly higher sound pressure level, less perturbation and a decrease in F3 after using medical masks. | IV |
| COVID-19: Acoustic Measures of Voice in Individuals Wearing Different Facemasks(26) | USA, 2021 | Cross-sectional study. n=19 |
With intervention of mask use. | Masks tested did not have a significant impact on intensity, fundamental frequency. frequency, PPC-s, frequency of the first or second formant compared to the unmasked speech output. | IV |
| Acoustic voice characteristics with and without wearing a facemask(27) | Australia, 2021 | Case-control, n=16 |
With intervention of mask use | The surgical mask has less impact than the KN95 on analyzed vocal aspects | IV |
| Are Acoustic Markers of Voice and Speech Signals Affected by Nose-and-Mouth-Covering Respiratory Protective Masks?(28) | Belgium, 2021 | Cross-sectional study n=50 |
With intervention of mask use | The surgical mask is preferred when spoken communication is a priority alongside respiratory protection. | IV |