COVID-19-related voice disorders: a scoping review

Silva, Aline de Souza; Nascimento, Isabella Marins Cassiano do; Dornelas, Rodrigo; Silva, José Roberto Lapa e

doi:10.1590/2317-1782/e20250243pt

person Aline de Souza Silva

conceptualization · data curation · investigation · methodology · writing-original draft · writing-review & editing

schoolFaculdade de Medicina, Universidade Federal do Rio de Janeiro – UFRJ - Rio de Janeiro (RJ), Brasil.

0009-0009-9120-6226

person Isabella Marins Cassiano do Nascimento

conceptualization · data curation · investigation · methodology · writing-original draft · writing

schoolFaculdade de Medicina, Universidade Federal do Rio de Janeiro – UFRJ - Rio de Janeiro (RJ), Brasil.

0009-0000-7634-5310

person Rodrigo Dornelas

writing-original draft · writing-review & editing

schoolFaculdade de Medicina, Universidade Federal do Rio de Janeiro – UFRJ - Rio de Janeiro (RJ), Brasil.

0000-0002-9710-5751

person José Roberto Lapa e Silva

writing-review & editing

schoolFaculdade de Medicina, Universidade Federal do Rio de Janeiro – UFRJ - Rio de Janeiro (RJ), Brasil.

0000-0003-3116-0253

Conflict of interests:

nothing to declare.

personCorrespondence address: Aline de Souza Silva Faculdade de Medicina, Universidade Federal do Rio de Janeiro – UFRJ R. Antônio Barros de Castro, 119, Cidade Universitária, Rio de Janeiro (RJ), Brasil, CEP: 21941-853. E-mail:
fgaalinesilva@medicina.ufrj.br

Editor:

Aline Mansueto Mourão.

Figures (3)
Tables (6)

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Figure 1 Distribution of articles included in the scope review by nationality

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Figure 2 Vocal signs and symptoms associated with COVID-19

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Figure 3 Frequency of vocal assessment protocols used

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Base de dados Data Estratégia de busca Número de artigos MEDLINE/PUBMED junho/2024 ((“COVID-19”[Mesh] OR “2019 Novel Coronavirus Disease”[tiab] OR “2019 Novel Coronavirus Infection”[tiab] OR “2019-nCoV Disease”[tiab] OR “2019-nCoV Infection”[tiab] OR “COVID19 Coronavirus Disease “[tiab] OR “Coronavirus Disease-19”[tiab] OR “SARS Coronavirus 2 Infection”[tiab] OR “SARS-CoV-2 Infection”[tiab] OR “Severe Acute Respiratory Syndrome Coronavirus 2 Infection”[tiab] OR “Covid 19”[tiab] OR “covid-19”[tiab] OR “covid19”[tiab] OR “coronavirus”[tiab] OR “SARS-COV-2”[tiab] OR “SARS-COV2” [tiab] OR “COVID disease”[tiab] OR “COVID sequelae”[tiab] OR ”COVID complications”[tiab] OR “COVID survivors”[tiab] OR “COVID infection” [tiab] OR “COVID infections”[tiab]) AND (“Voice Quality”[Mesh] OR “Voice”[Mesh] OR “Voice Qualities”[tiab] OR “Voices”[tiab] OR “Voice Disorders“[tiab] OR “Voice Disturbance “[tiab] OR “Voice Disturbances “[tiab] OR “Voice”[tiab] OR “Vocal quality”[tiab] OR “Voice quality”[tiab] OR “vocal health”[tiab] OR “voice health”[tiab] OR “vocal disorder”[tiab] OR “voice production”[tiab] OR “voice pathology”[tiab] OR “voice dysfunction”[tiab] OR “vocal dysfunction”[tiab])) 1509 EMBASE junho/2024 ('covid 19'/exp OR '2019 novel coronavirus disease':ti,ab OR '2019 novel coronavirus infection':ti,ab OR '2019-ncov disease':ti,ab OR '2019-ncov infection':ti,ab OR 'covid19 coronavirus disease':ti,ab OR 'coronavirus disease-19':ti,ab OR 'sars coronavirus 2 infection':ti,ab OR 'sars-cov-2 infection':ti,ab OR 'severe acute respiratory syndrome coronavirus 2 infection':ti,ab OR 'covid 19':ti,ab OR 'covid-19':ti,ab OR 'covid19':ti,ab OR 'coronavirus':ti,ab OR 'sars-cov-2':ti,ab OR 'sars-cov2':ti,ab OR 'covid disease':ti,ab OR 'covid sequelae':ti,ab OR 'covid complications':ti,ab OR 'covid survivors':ti,ab OR 'covid infection':ti,ab OR 'covid infections':ti,ab) AND ('voice quality'/exp OR 'voice'/exp OR 'voice qualities':ti,ab OR 'voices':ti,ab OR 'voice disorders':ti,ab OR 'voice disturbance':ti,ab OR 'voice disturbances':ti,ab OR 'voice':ti,ab OR 'vocal quality':ti,ab OR 'voice quality':ti,ab OR 'vocal health':ti,ab OR 'voice health':ti,ab OR 'vocal disorder':ti,ab OR 'voice production':ti,ab OR 'voice pathology':ti,ab OR 'voice dysfunction':ti,ab OR 'vocal dysfunction':ti,ab) 1765 LILACS junho/2024 ((mh:(“COVID-19” OR “Voice Quality” OR “Voice”)) OR (tw:(“2019 Novel Coronavirus Disease” OR “2019 Novel Coronavirus Infection” OR “2019-nCoV Disease” OR “2019-nCoV Infection” OR “COVID19 Coronavirus Disease” OR “Coronavirus Disease-19” OR “SARS Coronavirus 2 Infection” OR “SARS-CoV-2 Infection” OR “Severe Acute Respiratory Syndrome Coronavirus 2 Infection” OR “Covid 19” OR “covid-19” OR “covid19” OR “coronavirus” OR “SARS-COV-2” OR “SARS-COV2” OR “COVID disease” OR “COVID sequelae” OR “COVID complications” OR “COVID survivors” OR “COVID infection” OR “COVID infections”))) AND ((mh:(“Voice Quality” OR “Voice”)) OR (tw:(“Voice Qualities” OR “Voices” OR “Voice Disorders” OR “Voice Disturbance” OR “Voice Disturbances” OR “Voice” OR “Vocal quality” OR “Voice quality” OR “vocal health” OR “voice health” OR “vocal disorder” OR “voice production” OR “voice pathology” OR “voice dysfunction” OR “vocal dysfunction”))) 279 SCOPUS junho/2024 ((INDEXTERMS (“COVID-19”) OR INDEXTERMS (“Voice Quality”) OR INDEXTERMS (“Voice”)) OR (TITLE-ABS-KEY (“2019 Novel Coronavirus Disease” OR “2019 Novel Coronavirus Infection” OR “2019-nCoV Disease” OR “2019-nCoV Infection” OR “COVID19 Coronavirus Disease” OR “Coronavirus Disease-19” OR “SARS Coronavirus 2 Infection” OR “SARS-CoV-2 Infection” OR “Severe Acute Respiratory Syndrome Coronavirus 2 Infection” OR “Covid 19” OR “covid-19” OR “covid19” OR “coronavirus” OR “SARS-COV-2” OR “SARS-COV2” OR “COVID disease” OR “COVID sequelae” OR “COVID complications” OR “COVID survivors” OR “COVID infection” OR “COVID infections”))) AND ((INDEXTERMS (“Voice Quality”) OR INDEXTERMS (“Voice”)) OR (TITLE-ABS-KEY (“Voice Qualities” OR “Voices” OR “Voice Disorders” OR “Voice Disturbance” OR “Voice Disturbances” OR “Voice” OR “Vocal quality” OR “Voice quality” OR “vocal health” OR “voice health” OR “vocal disorder” OR “voice production” OR “voice pathology” OR “voice dysfunction” OR “vocal dysfunction”))) 20.000 Web of science junho/2024 ((TS=(“2019 Novel Coronavirus Disease” OR “2019 Novel Coronavirus Infection” OR “2019-nCoV Disease” OR “2019-nCoV Infection” OR “COVID19 Coronavirus Disease” OR “Coronavirus Disease-19” OR “SARS Coronavirus 2 Infection” OR “SARS-CoV-2 Infection” OR “Severe Acute Respiratory Syndrome Coronavirus 2 Infection” OR “Covid 19” OR “covid-19” OR “covid19” OR “coronavirus” OR “SARS-COV-2” OR “SARS-COV2” OR “COVID disease” OR “COVID sequelae” OR “COVID complications” OR “COVID survivors” OR “COVID infection” OR “COVID infections”)) AND (TS=(“Voice Qualities” OR “Voices” OR “Voice Disorders” OR “Voice Disturbance” OR “Voice Disturbances” OR “Voice” OR “Vocal quality” OR “Voice quality” OR “vocal health” OR “voice health” OR “vocal disorder” OR “voice production” OR “voice pathology” OR “voice dysfunction” OR “vocal dysfunction”))) 2858 Cochrane junho/2024 #1 MeSH descriptor: COVID-19 #2 MeSH descriptor: Voice Quality #3 MeSH descriptor: Voice,#4:ti,ab,kw “2019 Novel Coronavirus Disease” OR “2019 Novel Coronavirus Infection” OR “2019-nCoV Disease” OR “2019-nCoV Infection” OR “COVID19 Coronavirus Disease” OR “Coronavirus Disease-19” OR “SARS Coronavirus 2 Infection” OR “SARS-CoV-2 Infection” OR “Severe Acute Respiratory Syndrome Coronavirus 2 Infection” OR “Covid 19” OR “covid-19” OR “covid19” OR “coronavirus” OR “SARS-COV-2” OR “SARS-COV2” OR “COVID disease” OR “COVID sequelae” OR “COVID complications” OR “COVID survivors” OR “COVID infection” OR “COVID infections” #5:ti,ab,kw “Voice Qualities” OR “Voices” OR “Voice Disorders” OR “Voice Disturbance” OR “Voice Disturbances” OR “Voice” OR “Vocal quality” OR “Voice quality” OR “vocal health” OR “voice health” OR “vocal disorder” OR “voice production” OR “voice pathology” OR “voice dysfunction” OR “vocal dysfunction” #6 #1 OR #2 OR #3 OR #4 #7 #5 #8 #6 AND #7 474 Literatura Cinzenta Data Estratégia de busca Número de artigos ProQuest janeiro/2025 (“COVID-19”) AND (“Voice Quality”) 3.103 MedRxiv janeiro/2025 (“COVID-19”) AND (“Voice Quality”) 1.349 Google Scholar janeiro/2025 (“COVID-19”) AND (“Voice Quality”) 2019-2025 4.160

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Table 1 Study characteristics - part I

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Table 2 Study characteristics - part II

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Table 3 Clinical context found in the studies

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Table 4 Vocal assessments found in studies

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Database Date Search strategy Number of articles MEDLINE/PubMed June 2024 ((“COVID-19”[Mesh] OR "2019 Novel Coronavirus Disease”[tiab] OR "2019 Novel Coronavirus Infection”[tiab] OR "2019-nCoV Disease”[tiab] OR "2019-nCoV Infection”[tiab] OR “COVID19 Coronavirus Disease “[tiab] OR "Coronavirus Disease-19”[tiab] OR "SARS Coronavirus 2 Infection”[tiab] OR "SARS-CoV-2 Infection”[tiab] OR "Severe Acute Respiratory Syndrome Coronavirus 2 Infection”[tiab] OR "Covid 19"[tiab] OR "covid-19"[tiab] OR “covid19"[tiab] OR “coronavirus"[tiab] OR “SARS-COV-2”[tiab] OR "SARS-COV2" [tiab] OR "COVID disease”[tiab] OR “COVID sequelae”[tiab] OR ”COVID complications”[tiab] OR “COVID survivors”[tiab] OR “COVID infection” [tiab] OR “COVID infections”[tiab]) AND ("Voice Quality”[Mesh] OR “Voice”[Mesh] OR "Voice Qualities”[tiab] OR “Voices"[tiab] OR "Voice Disorders“[tiab] OR “Voice Disturbance “[tiab] OR “Voice Disturbances “[tiab] OR “Voice”[tiab] OR "Vocal quality”[tiab] OR "Voice quality”[tiab] OR "vocal health”[tiab] OR "voice health”[tiab] OR "vocal disorder”[tiab] OR "voice production”[tiab] OR "voice pathology”[tiab] OR "voice dysfunction"[tiab] OR "vocal dysfunction”[tiab])) 1,509 EMBASE June 2024 ('covid 19'/exp OR '2019 novel coronavirus disease':ti,ab OR '2019 novel coronavirus infection':ti,ab OR '2019-ncov disease':ti,ab OR '2019-ncov infection':ti,ab OR 'covid19 coronavirus disease':ti,ab OR 'coronavirus disease-19':ti,ab OR 'sars coronavirus 2 infection':ti,ab OR 'sars-cov-2 infection':ti,ab OR 'severe acute respiratory syndrome coronavirus 2 infection':ti,ab OR 'covid 19':ti,ab OR 'covid-19':ti,ab OR 'covid19':ti,ab OR 'coronavirus':ti,ab OR 'sars-cov-2':ti,ab OR 'sars-cov2':ti,ab OR 'covid disease':ti,ab OR 'covid sequelae':ti,ab OR 'covid complications':ti,ab OR 'covid survivors':ti,ab OR 'covid infection':ti,ab OR 'covid infections':ti,ab) AND ('voice quality'/exp OR 'voice'/exp OR 'voice qualities':ti,ab OR 'voices':ti,ab OR 'voice disorders':ti,ab OR 'voice disturbance':ti,ab OR 'voice disturbances':ti,ab OR 'voice':ti,ab OR 'vocal quality':ti,ab OR 'voice quality':ti,ab OR 'vocal health':ti,ab OR 'voice health':ti,ab OR 'vocal disorder':ti,ab OR 'voice production':ti,ab OR 'voice pathology':ti,ab OR 'voice dysfunction':ti,ab OR 'vocal dysfunction':ti,ab) 1,765 LILACS June 2024 ((mh:("COVID-19" OR "Voice Quality" OR "Voice")) OR (tw:("2019 Novel Coronavirus Disease" OR "2019 Novel Coronavirus Infection" OR "2019-nCoV Disease" OR "2019-nCoV Infection" OR "COVID19 Coronavirus Disease" OR "Coronavirus Disease-19" OR "SARS Coronavirus 2 Infection" OR "SARS-CoV-2 Infection" OR "Severe Acute Respiratory Syndrome Coronavirus 2 Infection" OR "Covid 19" OR "covid-19" OR "covid19" OR "coronavirus" OR "SARS-COV-2" OR "SARS-COV2" OR "COVID disease" OR "COVID sequelae" OR "COVID complications" OR "COVID survivors" OR "COVID infection" OR "COVID infections"))) AND ((mh:("Voice Quality" OR "Voice")) OR (tw:("Voice Qualities" OR "Voices" OR "Voice Disorders" OR "Voice Disturbance" OR "Voice Disturbances" OR "Voice" OR "Vocal quality" OR "Voice quality" OR "vocal health" OR "voice health" OR "vocal disorder" OR "voice production" OR "voice pathology" OR "voice dysfunction" OR "vocal dysfunction"))) 279 SCOPUS June 2024 ( ( INDEXTERMS ( "COVID-19" ) OR INDEXTERMS ( "Voice Quality" ) OR INDEXTERMS ( "Voice" ) ) OR ( TITLE-ABS-KEY ( "2019 Novel Coronavirus Disease" OR "2019 Novel Coronavirus Infection" OR "2019-nCoV Disease" OR "2019-nCoV Infection" OR "COVID19 Coronavirus Disease" OR "Coronavirus Disease-19" OR "SARS Coronavirus 2 Infection" OR "SARS-CoV-2 Infection" OR "Severe Acute Respiratory Syndrome Coronavirus 2 Infection" OR "Covid 19" OR "covid-19" OR "covid19" OR "coronavirus" OR "SARS-COV-2" OR "SARS-COV2" OR "COVID disease" OR "COVID sequelae" OR "COVID complications" OR "COVID survivors" OR "COVID infection" OR "COVID infections" ) ) ) AND ( ( INDEXTERMS ( "Voice Quality" ) OR INDEXTERMS ( "Voice" ) ) OR ( TITLE-ABS-KEY ( "Voice Qualities" OR "Voices" OR "Voice Disorders" OR "Voice Disturbance" OR "Voice Disturbances" OR "Voice" OR "Vocal quality" OR "Voice quality" OR "vocal health" OR "voice health" OR "vocal disorder" OR "voice production" OR "voice pathology" OR "voice dysfunction" OR "vocal dysfunction" ) ) ) 20,000 Web of science June 2024 ((TS=("2019 Novel Coronavirus Disease" OR "2019 Novel Coronavirus Infection" OR "2019-nCoV Disease" OR "2019-nCoV Infection" OR "COVID19 Coronavirus Disease" OR "Coronavirus Disease-19" OR "SARS Coronavirus 2 Infection" OR "SARS-CoV-2 Infection" OR "Severe Acute Respiratory Syndrome Coronavirus 2 Infection" OR "Covid 19" OR "covid-19" OR "covid19" OR "coronavirus" OR "SARS-COV-2" OR "SARS-COV2" OR "COVID disease" OR "COVID sequelae" OR "COVID complications" OR "COVID survivors" OR "COVID infection" OR "COVID infections")) AND (TS=("Voice Qualities" OR "Voices" OR "Voice Disorders" OR "Voice Disturbance" OR "Voice Disturbances" OR "Voice" OR "Vocal quality" OR "Voice quality" OR "vocal health" OR "voice health" OR "vocal disorder" OR "voice production" OR "voice pathology" OR "voice dysfunction" OR "vocal dysfunction"))) 2,858 Cochrane June 2024 #1 MeSH descriptor: COVID-19 #2 MeSH descriptor: Voice Quality #3 MeSH descriptor: Voice #4 :ti,ab,kw "2019 Novel Coronavirus Disease" OR "2019 Novel Coronavirus Infection" OR "2019-nCoV Disease" OR "2019-nCoV Infection" OR "COVID19 Coronavirus Disease" OR "Coronavirus Disease-19" OR "SARS Coronavirus 2 Infection" OR "SARS-CoV-2 Infection" OR "Severe Acute Respiratory Syndrome Coronavirus 2 Infection" OR "Covid 19" OR "covid-19" OR "covid19" OR "coronavirus" OR "SARS-COV-2" OR "SARS-COV2" OR "COVID disease" OR "COVID sequelae" OR "COVID complications" OR "COVID survivors" OR "COVID infection" OR "COVID infections" #5 :ti,ab,kw "Voice Qualities" OR "Voices" OR "Voice Disorders" OR "Voice Disturbance" OR "Voice Disturbances" OR "Voice" OR "Vocal quality" OR "Voice quality" OR "vocal health" OR "voice health" OR "vocal disorder" OR "voice production" OR "voice pathology" OR "voice dysfunction" OR "vocal dysfunction" #6 #1 OR #2 OR #3 OR #4 #7 #5 #8 #6 AND #7 474 Gray Literature Date Search strategy Number of articles ProQuest January 2025 ("COVID-19") AND ("Voice Quality") 3,103 MedRxiv January 2025 ("COVID-19") AND ("Voice Quality") 1,349 Google Scholar January 2025 ("COVID-19") AND ("Voice Quality”) 2019-2025 4,160

Author(s)	Year	Country
Asiaee et al.(¹⁹)	2020	Iran
Helding et al.(⁹)	2020	USA
Eltelety and Nassar(²⁰)	2020	Egypt
Korkmaz and Güven⁽ ²¹)	2021	Turkey
Saki et al.(²²)	2021	Iran
Bartl-Pokorny et al.(²³)	2021	Germany
Tohidast et al.(²⁴)	2021	Iran
Dassie-Leite et al.(²⁵)	2021	Brazil
Azzam et al.(²⁶)	2021	Egypt
Gölaç et al.(¹²)	2022	Turkey
Aghadoost et al.(²⁷)	2022	Iran
Aghaz et al.(¹¹)	2022	Iran
Shanem et al.(²⁸)	2022	Pakistan
Khoddami et al.(¹³)	2023	Iran
Saki et al.(²⁹)	2023	Iran
Kuć and Michta(³⁰)	2023	Poland
Bueno et al.(¹⁰)	2024	Brazil
Rahul et al.(³¹)	2024	India
Berti et al.(³²)	2025	Switzerland

Article	Study type	Study objective	Sample size	Number of men	Number of women	Age range
Gölaç et al.(¹²)	observational, case-control	To compare the vocal outcomes of recovering patients with a control group.	80 (40 cases and 40 controls)	40	40	21 to 53 years
Korkmaz and Güven⁽ ²¹)	Case report	To present a case of sudden unilateral vocal cord paralysis believed to be associated with COVID-19 infection.	1	0	1	55 years
Saki et al.(²²)	Observational, case-control study	To conduct an auditory-perceptual evaluation of the vocal characteristics of patients with varying degrees of COVID-19 severity.	102	94	38	Patient group with a mean age of 58.1 ± 9.1 years. Healthy group with a mean age of 46.7 ± 9.3 years.
Bartl-Pokorny et al.(²³)	case control	To provide a deeper understanding of the voice characteristics of patients with COVID-19.	22	14	8	With COVID: mean age +/- 60 years +/- 20 years standard deviation; age range +/- 19-79 years; Without COVID: mean age +/- 55 years +/- 20 years standard deviation; age range +/- 24-85 years
Khoddami et al.(¹³)	observational and cross-sectional, case-control	To determine general health and voice-related QoL and investigate the correlation between them in Iranian patients with COVID-19 and healthy individuals.	68 (34 controls and 34 cases)	20	14	18 to 50 years
Saki et al.(²⁹)	cross-sectional, case-control	To compare signs and symptoms of vocal fatigue between patients with COVID-19 and people with normal voices.	60 (30 cases and 30 controls)	18 cases and 14 controls	12 cases and 16 controls	Mean age: 35.69 ± 6.92 years (controls) Mean age: 39.69 ± 10.42 years (cases)
Aghadoost et al.(²⁷)	cross-sectional, case-control	To investigate the correlation between subjective analysis and objective analysis of voice in patients with COVID-19 infection.	80 (40 cases and 40 controls)	27 men per group	13 women per group	Case group: (mean age 41.2 ± 5.41 years). Control group: mean age 44.50 ± 3.50 years.
Tohidast et al.(²⁴)	Case control	To investigate voice quality and symptoms of vocal tract discomfort in patients with COVID-19.	88 patients (44 cases and 44 controls)	24 per group	20 per group	The mean age of patients with COVID-19 and healthy individuals was 49.61 mean and 16.48 standard deviation and 48.52 mean and 13.8 standard deviation, respectively.
Dassie-Leite et al.(²⁵)	Observational, analytical, cross-sectional, and hybrid	Compare the occurrence of vocal signs and symptoms before, during, and after COVID-19 and analyze possible risk factors for the persistence of these symptoms after resolution of the disease.	45	21	24	Mean age of 44 years and 10 months
Asiaee et al.(¹⁹)	Observational, case-control	To compare patients with COVID-19 with healthy individuals to assess the effect of this disease on acoustic parameters.	64 cases and 70 controls (134)	38 cases and 33 controls	26 cases and 37 controls	Mean age of 52.3 years in the case group and 42.35 years in the control group.
Helding et al.(⁹)	Review/Discussion Article	To discuss the long-term effects of COVID-19 and its impact on the voice, with a focus on singers.	-	-	-	-
Aghaz et al.(¹¹)	systematic review and meta-analysis	To estimate the prevalence of dysphonia in patients with COVID-19.	1410	28.20%	32.80%	42.71 years
Azzam et al.(²⁶)	Clinical study	To detect the occurrence of vocal symptoms in COVID-19 patients in Egypt and to investigate the associated videolaryngoscopy findings.	106	28	78	18 to 66 years
Bueno et al.(¹⁰)	Observational study	To identify vocal impairments and changes in voice-related quality of life in patients with pulmonary impairment associated with COVID-19.	35	22	13	18 to 65 years
Shanem et al.(²⁸)	Retrospective cross-sectional study	To investigate the impact of COVID-19 on vocal cord function and voice production.	379	168	211	20 to 50 years
Kuć and Michta(³⁰)	Observational study	To diagnose the types of speech disorders that occur in COVID-19 survivors.	30	15	15	30 to 60 years
Berti et al.(³²)	Comparative study	To compare the voice and speech characteristics between post-COVID-19 individuals and control individuals.	134 (70 controls and 64 cases)	30 controls and 25 cases	40 controls and 39 cases	40 to 60 years
Eltelety and Nassar(²⁰)	case study	To report a patient with COVID-19 presenting primarily with hoarseness and anosmia.	1	1	0	27
Rahul et al.(³¹)	Case control	To explore the perceptual changes, self-reported outcomes, and acoustic changes in the voice of individuals infected with COVID-19 immediately after the isolation period and compare them with the control group.	25	0	25	18 to 40 years

Article	COVID-19 classification	different vaccination statuses	COVID-19 signs and symptoms	Vocal signs and symptoms
Gölaç et al.(¹²)	The article does not classify COVID-19.	Not reported	cough, shortness of breath, tiredness, difficulty speaking, and pain	Cough, shortness of breath, fatigue, difficulty speaking, and pain.
Korkmaz and Güven⁽ ²¹)	The article does not classify COVID-19.	Vaccinated against COVID-19 with two doses of the vaccine before being diagnosed with the infection.	Cough and shortness of breath, fever, fatigue, progressive hoarseness.	Hoarseness (dysphonia), difficulty speaking, vocal fatigue
Saki et al.(²²)	Mild, Moderate, Severe	Not reported	Not reported	Dysphonia, hoarseness, and difficulty controlling vocal production.
Bartl-Pokorny et al.(²³)	The COVID participants presented with mild to moderate respiratory symptoms.	Not reported	Mild to moderate respiratory symptoms.	Not reported
Khoddami et al.(¹³)	mild to moderate	Not reported	Absence of pneumonia, mild complications, fever, signs of pneumonia, and infection.	Not specified
Saki et al.(²⁹)	Not classified	Not specified	Cough, pharyngitis, sore throat, and difficulty breathing.	Vocal fatigue, hoarse voice, breathy voice, vocal strain, and voice breaks.
Aghadoost et al.(²⁷)	Mild to moderate COVID-19	Not reported	Pneumonia, fever, and other respiratory symptoms, but no respiratory failure requiring mechanical ventilation.	Dysphonia (voice alterations, such as hoarseness), reduction in vocal quality, with increased roughness, breathiness, tension and vocal effort, reduction in maximum phonation time
Tohidast et al.(²⁴)	Mild, moderate and severe (ICU)	Not reported	Not reported	Vocal discomfort (burning, pain, dryness, irritability and lump in the throat, tightness)
Dassie-Leite et al.(²⁵)	Mild, acute, severe, critical	Nor reported	cough, fever, dyspnea, musculoskeletal symptoms (myalgia, joint pain, fatigue), gastrointestinal symptoms, anosmia and dysgeusia.	laryngeal sensitivity and vocal changes, dysphonia,
Asiaee et al.(¹⁹)	Not reported	Not reported	Not reported	Not specified
Helding et al.(⁹)	Not applicable	Not applicable	respiratory, neurological and post-infectious symptoms	Review of evidence
Aghaz et al.(¹¹)	Not reported	Not reported	Specific signs and symptoms are not detailed.	Dysphonia
Azzam et al.(²⁶)	mild to moderate	Not reported	dysphonia, phonesthenia, nasal obstruction, loss of smell, taste dysfunction, sore throat, sticky mucus, and dysphagia	Dysphonia and phonesthenia
Bueno et al.(¹⁰)	Not reported	Not reported	dyspnea and cough	dysphonia, vocal fatigue and laryngospasm
Shanem et al.(²⁸)	Not reported	Not reported	Not reported	Weak and trembling voice, unclear voice and vocal changes
Kuć and Michta(³⁰)	Not reported	Not reported	Not reported	hoarseness, cough, pain when swallowing, and a feeling of a foreign body in the throat
Berti et al.(³²)	mild to moderate	Not reported	Runny nose, sore throat, cough, fever, headache, loss of taste/smell, fatigue, muscle aches and/or diarrhea.	Not reported
Eltelety and Nassar(²⁰)	Not reported	Not reported	Hoarseness and anosmia	Hoarseness
Rahul et al.(³¹)	Not reported	Not reported	Cough, dry throat, and phlegm.	difficulty increasing volume and other vocal problems

Article	Vocal assessment	Acoustic analysis
Gölaç et al.(¹²)	Acoustic Analysis	Acoustic Parameters Evaluated:
	Aerodynamic Measurement: MPT	Average Fundamental Frequency (F0)
	Self-Perception Questionnaires: Voice Handicap Index-10 (VHI-10), Voice-Related Quality of Life (V-RQOL)	Local Jitter
	Auditory-Perceptual Evaluation: CAPE-V	Local Shimmer
		Harmonic-to-Noise Ratio (HNR)
		Cepstral Peak Prominence (CPP).
		Methods and Tools Used:
		Software: Acoustic analyses were performed using Praat software (version 6.0.17).
		Voice Samples: collected through sustained phonation of the vowel /a/ and linked speech (third sentence of the CAPE-V protocol in Turkish).
		Analyzed Segment: For perturbation measures (jitter, shimmer, and HNR), the middle segment of the vowel /a/ in the most stable part of phonation was used. For the CPP, the third sentence of the CAPE-V protocol was analyzed.
Korkmaz and Güven⁽ ²¹)	Acoustic analysis	Fundamental Frequency (F0): The fundamental frequency, or pitch, was measured to verify the variation in voice tone, since unilateral paralysis can affect the symmetry of vocal cord movement and, consequently, the frequency of vocal emission.
	Voice Handicap Index (VHI) assessment	Jitter: refers to the variation in the fundamental frequency of the voice and can be used to assess the stability of vocal tone. Paralysis can cause fluctuations in tone, reflecting vocal irregularity.
	Laryngoscopy: Direct laryngoscopy was performed to examine the vocal cords and identify unilateral paralysis.	Shimmer: measures the variation in sound amplitude, indicating the regularity of vocal intensity. Vocal cord paralysis can affect the consistency of vocal production, altering the shimmer.
	Aerodynamic measurement: MPT, using the s/z ratio.	Vocal Quality Index: Parameters such as sound regularity (measured by jitter and shimmer) are frequently used to assess vocal quality. In the case of vocal paralysis, these parameters may be altered, reflecting compromised vocal quality.
Saki et al.(²²)	Auditory-Perceptual Evaluation: GRBAS	Acoustic analysis was performed to evaluate parameters such as fundamental frequency (F0), intensity, and disturbances in voice frequency and amplitude, providing a more objective assessment of the alterations.
Bartl-Pokorny et al.(²³)	This study analyzed recordings of sustained vowels (/i:/, /e:/, /o:/, /u:/, and /a:/) produced by German-speaking participants. The research focused on 88 acoustic characteristics extracted from these recordings, without specifying traditional vocal assessment protocols such as maximum phonation duration or vocal intensity. Statistical analysis was performed using the Mann-Whitney U test and effect size calculations to identify significant differences between the participant groups.	The acoustic analysis included the following parameters:
		Fundamental frequency (F0): The average frequency of the voice, which can reflect changes in vocal control and vocal cord tension.
		Harmonic-to-noise ratio (HNR): A measure that indicates the clarity of the voice. The lower the HNR ratio, the greater the presence of noise in the voice.
		Mel's cepstral coefficients (MFCC): Spectral characteristics that help describe the acoustic content of the voice in a way that simulates human auditory perception.
		Spectral slope: Reflects how energy is distributed across the frequencies of the vocal sound.
		Vowel duration and number of sound segments per second: Indicators of the rhythm and fluency of vocal production.
Khoddami et al.(¹³)	Voice Handicap Index (VHI): This index is a widely used tool to assess the impact of vocal dysfunction on individuals' quality of life. It helps measure the degree of discomfort and limitation that vocal problems cause in patients' daily lives.	It does not mention whether it conducted acoustic analyses of the participants' voices.
Khoddami et al.(¹³)	Health-related quality of life assessment: Although the study does not provide specific details on the exact protocol used to measure quality of life, it is mentioned that quality of life assessment was an important part of the analysis, comparing patients recovered from COVID-19 with healthy subjects.
Saki et al.(²⁹)	Acoustic Evaluation of the Voice	Evaluated Parameters: Jitter (%), Shimmer (%), MPT (seconds), HNR (dB).
	Auditory-perceptual evaluation: CAPE-V	Results:
	Self-perception questionnaire: Vocal Fatigue Index	Patients with COVID-19 presented higher Jitter, Shimmer, and lower HNR and MPT compared to the control group.
		Prolonged voice use (after reading the text) exacerbated vocal irregularities in patients with COVID-19.
		Correlations:
		The acoustic parameters (Jitter, Shimmer, HNR) correlated significantly with vocal fatigue (voice tiredness and physical discomfort).
Aghadoost et al.(²⁷)	Auditory-perceptual evaluation: CAPE-V	Frequency Disturbance (Jitter): Higher Fundamental Frequency (F0 high)
Aghadoost et al.(²⁷)	Self-perception questionnaire: Dysphonia Severity Index (DSI)
Tohidast et al.(²⁴)	Auditory-perceptual evaluation: GRBAS	Not performed
Tohidast et al.(²⁴)	Self-perception questionnaire: VTD (vocal tract discomfort)	Not performed
Dassie-Leite et al.(²⁵)	Vocal Signs and Symptoms list (SSL), which investigates the presence or absence of 14 vocal signs or symptoms. A translation of the instrument into Brazilian Portuguese was used. Each symptom was addressed in relation to three distinct moments: before, during, and after COVID-19.	Not performed
Asiaee et al.(¹⁹)	Acoustic analysis	A Praat script was used to extract the local values of jitter, shimmer, MPT, and the number of voice breaks. Measurements were performed using the default settings in Praat. Fundamental frequency, CPP, HNRs, and (H1-H2) were automatically extracted using VoiceSauce, a freeware for voice analysis.
		The F0 measurement was performed using the standard VoiceSauce algorithm, namely STRAIGHT. In VoiceSauce, CPP is calculated using the algorithm proposed by Hillenbrand et al. HNR values are measured using a variable window of five pitch periods by Krom's algorithm. HNR05, HNR15, HNR25, and HNR35 measure HNR from 0-500 Hz, 0-1500 Hz, 0-2500 Hz, and 0-3500 Hz, respectively. This study used HNR35 (hereinafter HNR).
		Finally, H1-H2 was used for evaluation (H1-H2), which is H1-H2 corrected for the formant effect based on the algorithm proposed by Iseli et al. and used in VoiceSauce.
Helding et al.(⁹)	Review of studies using acoustic and perceptual methods	Not applicable
Aghaz et al.(¹¹)	The contexts do not provide specific vocal assessment protocols used in the studies.	The contexts do not provide details about any acoustic analysis performed..
Azzam et al.(²⁶)	Includes auditory-perceptual evaluation of voice and videolaryngoscopy examination.	Not mentioned in the contexts provided.
Bueno et al.(¹⁰)	Voice Handicap Index 10 (VHI-10) and the Voice-Related Quality of Life (VQOL) and MPT protocol	Not specified in the contexts provided.
Shanem et al.(²⁸)	The Voice Handicap Index (VHI) was used to assess voice concerns.	Not performed
Kuć and Michta(³⁰)	It included recordings of spontaneous speech, repetition of words and phrases, a monologue, and automated word sequences; perceptual assessment was conducted using the GRBAS scale.	Not specified in the contexts provided.
Berti et al.(³²)	The recordings were made using SPIRA software based on three verbal tasks: sustained production of the vowel /a/, reading a sentence, and producing a rhyme.	Conducted using PRAAT software, focusing on various acoustic parameters.
Eltelety and Nassar(²⁰)	A follow-up transcervical laryngeal ultrasound was performed to assess vocal fold mobility.	Not specified
Rahul et al.(³¹)	Perceptual assessment, self-reported results using the Voice Handicap Index (VHI-10), and acoustic analysis.	The study revealed significant differences in acoustic parameters between the experimental and control groups.