Diagnostic validity of methods for assessment of swallowing sounds: a systematic review

Taveira, Karinna Veríssimo Meira; Santos, Rosane Sampaio; Leão, Bianca Lopes Cavalcante de; Stechman Neto, José; Pernambuco, Leandro; Silva, Letícia Korb da; Canto, Graziela De Luca; Porporatti, André Luís

doi:10.1016/j.bjorl.2017.12.008

Karinna Veríssimo Meira Taveira ^** Corresponding author. E-mails:karinnavm@hotmail.com, karinna@cb.ufrn.br (K.V. Taveira).

Universidade Federal do Rio Grande do Norte (UFRN), Departamento de Morfologia, Centro de Biociências, Natal, RN, Brazil

Rosane Sampaio Santos

Universidade Tuiuti do Paraná (UTP), Programa de Pós-graduação em Distúrbios da Comunicação, Curitiba, PR, Brazil

Bianca Lopes Cavalcante de Leão

Universidade Tuiuti do Paraná (UTP), Departamento de Odontologia, Curitiba, PR, Brazil

José Stechman Neto

Universidade Tuiuti do Paraná (UTP), Programa de Pós-graduação em Distúrbios da Comunicação, Curitiba, PR, Brazil

Leandro Pernambuco

Universidade Federal da Paraíba (UFPB), Departamento de Fonoaudiologia, João Pessoa, PB, Brazil

Letícia Korb da Silva

Instituto de Educação Luterana de Santa Catarina, Departamento de Fonoaudiologia, Joinville, SC, Brazil

Graziela De Luca Canto

Universidade Federal de Santa Catarina (UFSC), Departamento de Odontologia, Brazilian Centre for Evidence-based Research, Florianópolis, SC, Brazil

University of Alberta, Faculty of Medicine and Dentistry, School of Dentistry, Alberta, Canada

André Luís Porporatti

Universidade Federal de Santa Catarina (UFSC), Departamento de Odontologia, Brazilian Centre for Evidence-based Research, Florianópolis, SC, Brazil

* Corresponding author. E-mails:karinnavm@hotmail.com, karinna@cb.ufrn.br (K.V. Taveira).

Conflicts of interest

The authors declare no conflicts of interest.

Figures (4)
Tables (6)

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Figure 1
Flow diagram of literature search and selection criteria.¹1 Logemann JA. Evaluation and treatment of swallowing disorders. Nat Student Speech Lang Hear Assoc J. 1984;:38-50.

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Figure 2
Results from QUADAS-2 study quality assessment (A, risk of bias graph; B, risk of bias summary).

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Figure 3
Coupled forest plot of the sensitivity and specificity in videofluroscopic swallowing studies compared and swallow sounds (n = 3).

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Figure 4
ROC curves of the sensitivity and specificity in videofluroscopic swallowing studies compared and swallow sounds.

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Table 1
Summary of descriptive characteristics and outcomes of interest of the included studies (n = 3).

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Table 2
Diagnostic test validity data (n = 3).

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Database Search (October 8th 2016; updated on January 25th, 2017) Cochrane "deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow" in Title, Abstract, Keywords and videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies in Title, Abstract, Keywords and ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone in Title, Abstract, Keywords in Trials' LILACS (tw:("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow")) AND (tw:(videofluoroscopy OR "videofluoroscopy swallowing study" OR vfss OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies)) AND (tw:(ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone)) PubMed ("deglutition"[MeSH Terms] OR "deglutition"[All Fields] OR "deglutitions"[All Fields] OR "swallowing"[All Fields] OR "swallowings"[All Fields] OR "swallows"[MeSH Terms] OR "swallows"[All Fields] OR "swallow"[All Fields]) AND (videofluoroscopy[All Fields] OR "videofluoroscopy swallowing study"[All Fields] OR VFSS OR "videofluoroscopy study"[All Fields] OR "swallowing videofluoroscopy"[All Fields] OR videofluoroscopic[All Fields] OR "videofluoroscopic swallowing"[All Fields] OR "videofluoroscopic swallowing study"[All Fields] OR fluoroscopy[MeSH Terms] OR fluoroscopy[All Fields] OR fluoroscopies) AND (ultrasonography[Subheading] OR ultrasonography[All Fields] OR ultrasound[All Fields] OR ultrasonography[MeSH Terms] OR ultrasound[All Fields] OR ultrasonics[MeSH Terms] OR ultrasonics[Text Word] OR ultrasonics[All Fields] OR "duplex doppler ultrasonography"[All Fields] OR "doppler duplex ultrasonography"[All Fields] OR "acoustic analysis"[All Fields] OR "acoustical analysis"[All Fields] OR auscultation[MeSH Terms] OR auscultation[All Fields] OR "cervical auscultation"[All Fields] OR accelerometry[MeSH Terms] OR accelerometry[All Fields] OR "swallowing accelerometry signals"[All Fields] OR "swallowing sounds"[All Fields] OR "swallow sounds"[All Fields] OR "signal processing"[All Fields] OR acoustics[MeSH Terms] OR acoustics[All Fields] OR acoustic[All Fields] OR "doppler effect"[MeSH Terms] OR doppler effect[Text Word] OR "doppler effect"[All Fields] OR "doppler shift" OR "shift, doppler" OR "effect, doppler" OR "sonar doppler"[All Fields] OR microphone[All Fields]) Scopus (TITLE-ABS-KEY("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow") AND TITLE-ABS-KEY(videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies) AND TITLE-ABS-KEY(ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone)) Web of Science Tópico:("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow") ANDTópico: (videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies)AND Tópico: (ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone)) Google Scholar "deglutition OR swallowing:videofluoroscopy" Open Grey Swallowing OR deglutition AND videofluoroscopy AND "acoustic analysis" ProQuest Swallowing OR deglutition AND videofluoroscopy AND "acoustic analysis"

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Test indicators Data analysis References DOR The value of a DOR ranges from 0 to infinity, with higher values indicating better discriminatory test performance. A value of 1 means that a test does not discriminate between patients with the disorder and those without it. Values lower than 1 point to improper test interpretation (more negative tests among the diseased). Glas et al.37 LRs >1 - diagnostic of interest McGee25 0 and 1 - against the diagnosis of interest 0 - less likely the disease =1 - lack diagnostic valeu Sensitivity 80% excellent, 70-80% good, 60-69% fair, <60% poor No consensus in this regard exists in the literature. Specificity 90% excellent, 80-90% good, 70-79% fair, <70% poor No consensus in this regard exists in the literature. Youden's Index Youden's Index values close to 1 indicate high accuracy; a value of zero is equivalent to uninformed guessing and indicates that a test has no diagnostic value. Deeks et al.38

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Author, year Reason for exclusion Dudik et al., 201639 3 Dudik et al., 201540 3 Dudik et al., 201641 3 Frakking et al., 201642 3 Frakking et al., 201643 3 Golabbakhsh et al., 201444 3 Lee et al., 200645 3 Mérey et al., 201246 3 Morinière et al., 201147 3 Movahedi et al., 201648 3 Nikjoo et al., 201132 3 Reddy et al., 200049 3 Sejdic et al., 201450 3 Seidic et al., 201351 3 Selley et al., 199452 3 Spadotto et al., 200953 3 Spadotto et al., 200854 3 Steele et al., 201355 3 Stroud et al., 200256 3 Tanaka et al., 201257 3 Zoratto et al., 201058 3 Lazareck et al., 200459 3 Exclusion criteria: (1) studies in animals; (2) studies that did not performed ultrasound, acoustic analysis, cervical auscultation, swallowing accelerometry signals and doppler effect; (3) studies that do not compare methods of diagnosis of swallowing for both control and dysphagic group with the reference standard (videofluoroscopy); (4) studies that do not present validity measurements (sensitivity and specificity) or did not present data enough to calculate them; (5) reviews, letters, conference, abstract, personal opinions.

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Item Abdulmassih et al., 201318 Jayatilake et al., 201519 Leslie et al., 200420 Domain 1: Patient selection Was a consecutive or random sample of patients enrolled? N N N Was a case-control design avoided? N N N Did the study avoid inappropriate exclusions? Y Y Y Could the selection of patients have introduced bias? H H H Concerns regarding applicability: Are there concern that the included patients and settings do not match the review question? L L L Domain 2: Index test Were the index test results interpreted without knowledge of the results of the reference standard? U U U If a threshold was used, was it prespecified? Y Y Y Could the conduct or interpretation of the index test have introduced bias? U U L Concerns regarding applicability: Are there concerns that the index test, its conduct, or its interpretation differ from the review question? L L L Domain 3: Reference standard Is the reference standard likely to correctly classify the target condition? Y Y Y Were the reference standard results interpreted without knowledge of the results of the index test? U U U Could the reference standard, its conduct, or its interpretation have introduced bias? L L L Concerns regarding applicability: Are there concerns that the target condition as defined by the reference standard does not match the question? L L L Domain 4: Flow and timing Was there an appropriate interval between index test(s) and reference standard? Y Y Y Did all patients receive the same reference standard? Y Y Y Were all patients included in the analysis? Y N N Could the patient flow have introduced bias? L L L Y, yes; N, no; U, unclear; Risk: L, low; H, high; U, unclear.

Author, year, country	Mean age range (years)	Sample size nº of patients	Sample size nº of observations	Index test	Reference test	Description	Outcome	Conclusion
Abdulmassih et al., 2013, Brazil¹⁸18 David MAL, Alessandro L, Jennifer T, Douglas GA. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;7:1-6.	46.4 (28-62) healthy	30 healthy	30 healthy	Doppler	VFSS Swallow material: liquid, 70 mL water and 30 mL of 100% barium sulfate; pudding, 70 mL of water, 30 mL of barium sulfate; solids, club social biscuits soaked in barium	Acoustic analysis of swallow	The prevalence in the dynamic evaluation of swallowing VFSS was by changes in the oral phase of swallowing. The analysis of variance of the averages found in each variable - frequency, intensity and duration of swallowing - shows there was a significant correlation when compared to the healthy individual curve.	In patients with SCA, the mean initial frequency, initial intensity, and final intensity were higher and the time and peak frequency were lower, demonstrating a pattern of cricopharyngeal opening very close to that found in normal populations.
	44.9 (28-62) dysphagic	30 dysphagic	30 dysphagic	Doppler		Acoustic analysis of swallow
Jayatilake et al., 2015, Japan¹⁹19 Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529-36.	(22-39) healthy	15 healthy	8 healthy	Microphone	VFSS Swallow material: group healthy, water swallow test; group dysphagic, 3 mL water mixed 25% barium	Real-time swallowing sound-processing algorithm for the automatic screening, quantitative evaluation, and the visualization of swallowing ability	71 dry swallows the automatic swallow recognition algorithm achieved sensitivity 93.9% healthy subjects; algorithm automatically detected all or some of the swallowing events of all the 31 subjects dysphagic, and the overall detection accuracy for the 92 swallowing episodes was 79.3%	Swallowscope can analyze swallowing sounds in realtime and generate quantitative results: the number of swallows and the swallowing duration, which can assist bedside screening, and share them through a cloud-based system. We achieved very good performances in terms of both the positive predictive value and sensitivity.
	68.8 dysphagic	70 dysphagic	31 dysphagic	Microphone
Leslie et al., 2004, United Kingdom²⁰20 Macaskill PGC, Deeks J, Harbord R, Takwoingi Y. Chapter 10: Analysing and presenting results. In: Collaboration C, editor. Cochrane handbook for systematic reviews of diagnostic test accuracy version 1.0. England: Birmingham; 2010.	72 (24-78) healthy	10 healthy	10 healthy	Stethoscope	VFSS Swallow material: 3 boluses each of 5, 20 mL thin barium and 5 mL yogurt	Acoustic analysis of swallow	Comparison with radiological defined aspiration/penetration yielded 66% specificity, 62% sensitivity, and majority consensus gave 90% specificity, 80% sensitivity for detecting normality of a swallow, when consensus is reached among the raters.	Improving the poor raters would improve the overall accuracy of this technique in predicting abnormality in swallowing. The group consensus correctly identified 17 of the 20 clips so we may speculate that the swallow sound contains audible cues that should in principle permit reliable classification.
	78 (65-90) dysphagic	14 dysphagic	10 dysphagic	Stethoscope		Acoustic analysis of swallow

Group	Author, year	Dysphasic sample size	Control sample size	Prevalence (%)	Sensitivity (%)	Specificity (%)	PPV	NPV	LR+	LR-	DOR	Youden's index
Doppler/VFSS	Abdulmassih et al., 2013¹⁸18 David MAL, Alessandro L, Jennifer T, Douglas GA. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;7:1-6.	24	30	50.0^a a Data calculated by the authors from information available in the article.	80.0^a a Data calculated by the authors from information available in the article.	100^a a Data calculated by the authors from information available in the article.	1.00^a a Data calculated by the authors from information available in the article.	0.83^a a Data calculated by the authors from information available in the article.	∞^a a Data calculated by the authors from information available in the article.	0.20^a a Data calculated by the authors from information available in the article.	∞^a a Data calculated by the authors from information available in the article.	0.80^a a Data calculated by the authors from information available in the article.
Microphone/VFSS	Jayatilake et al., 2015¹⁹19 Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529-36.	31	8	79.4	93.9	29.1^a a Data calculated by the authors from information available in the article.	0.83	0.55^a a Data calculated by the authors from information available in the article.	1.32^a a Data calculated by the authors from information available in the article.	0.20^a a Data calculated by the authors from information available in the article.	0.20^a a Data calculated by the authors from information available in the article.	0.23^a a Data calculated by the authors from information available in the article.
Stethoscope/VFSS	Leslie et al., 2004²⁰20 Macaskill PGC, Deeks J, Harbord R, Takwoingi Y. Chapter 10: Analysing and presenting results. In: Collaboration C, editor. Cochrane handbook for systematic reviews of diagnostic test accuracy version 1.0. England: Birmingham; 2010.	14	10	58.3^a a Data calculated by the authors from information available in the article.	62.0	66.0	0.71^a a Data calculated by the authors from information available in the article.	0.55^a a Data calculated by the authors from information available in the article.	1.82^a a Data calculated by the authors from information available in the article.	0.57^a a Data calculated by the authors from information available in the article.	3.16^a a Data calculated by the authors from information available in the article.	0.28^a a Data calculated by the authors from information available in the article.

Database	Search (October 8th 2016; updated on January 25th, 2017)
Cochrane	"deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow" in Title, Abstract, Keywords and videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies in Title, Abstract, Keywords and ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone in Title, Abstract, Keywords in Trials'
LILACS	(tw:("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow")) AND (tw:(videofluoroscopy OR "videofluoroscopy swallowing study" OR vfss OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies)) AND (tw:(ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone))
PubMed	("deglutition"[MeSH Terms] OR "deglutition"[All Fields] OR "deglutitions"[All Fields] OR "swallowing"[All Fields] OR "swallowings"[All Fields] OR "swallows"[MeSH Terms] OR "swallows"[All Fields] OR "swallow"[All Fields]) AND (videofluoroscopy[All Fields] OR "videofluoroscopy swallowing study"[All Fields] OR VFSS OR "videofluoroscopy study"[All Fields] OR "swallowing videofluoroscopy"[All Fields] OR videofluoroscopic[All Fields] OR "videofluoroscopic swallowing"[All Fields] OR "videofluoroscopic swallowing study"[All Fields] OR fluoroscopy[MeSH Terms] OR fluoroscopy[All Fields] OR fluoroscopies) AND (ultrasonography[Subheading] OR ultrasonography[All Fields] OR ultrasound[All Fields] OR ultrasonography[MeSH Terms] OR ultrasound[All Fields] OR ultrasonics[MeSH Terms] OR ultrasonics[Text Word] OR ultrasonics[All Fields] OR "duplex doppler ultrasonography"[All Fields] OR "doppler duplex ultrasonography"[All Fields] OR "acoustic analysis"[All Fields] OR "acoustical analysis"[All Fields] OR auscultation[MeSH Terms] OR auscultation[All Fields] OR "cervical auscultation"[All Fields] OR accelerometry[MeSH Terms] OR accelerometry[All Fields] OR "swallowing accelerometry signals"[All Fields] OR "swallowing sounds"[All Fields] OR "swallow sounds"[All Fields] OR "signal processing"[All Fields] OR acoustics[MeSH Terms] OR acoustics[All Fields] OR acoustic[All Fields] OR "doppler effect"[MeSH Terms] OR doppler effect[Text Word] OR "doppler effect"[All Fields] OR "doppler shift" OR "shift, doppler" OR "effect, doppler" OR "sonar doppler"[All Fields] OR microphone[All Fields])
Scopus	(TITLE-ABS-KEY("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow") AND TITLE-ABS-KEY(videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies) AND TITLE-ABS-KEY(ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone))
Web of Science	Tópico:("deglutition" OR "deglutitions" OR "swallowing" OR "swallowings" OR "swallows" OR "swallow") ANDTópico: (videofluoroscopy OR "Videofluoroscopy Swallowing Study" OR VFSS OR "videofluoroscopy study" OR "swallowing videofluoroscopy" OR videofluoroscopic OR "videofluoroscopic swallowing" OR "videofluoroscopic swallowing study" OR fluoroscopy OR fluoroscopies)AND Tópico: (ultrasonography OR ultrasound OR ultrasonics OR "duplex doppler ultrasonography" OR "doppler duplex ultrasonography" OR "acoustic analysis" OR "acoustical analysis" OR auscultation OR "cervical auscultation" OR accelerometry OR "swallowing accelerometry signals" OR "swallowing sounds" OR "swallow sounds" OR "signal processing" OR acoustics OR acoustic OR "doppler effect" OR "doppler shift" OR "sonar doppler" OR microphone))
Google Scholar	"deglutition OR swallowing:videofluoroscopy"
Open Grey	Swallowing OR deglutition AND videofluoroscopy AND "acoustic analysis"
ProQuest	Swallowing OR deglutition AND videofluoroscopy AND "acoustic analysis"

Test indicators	Data analysis	References
DOR	The value of a DOR ranges from 0 to infinity, with higher values indicating better discriminatory test performance. A value of 1 means that a test does not discriminate between patients with the disorder and those without it. Values lower than 1 point to improper test interpretation (more negative tests among the diseased).	Glas et al.³⁷37 Glas AS, Lijmer JG, Prins MH, Bonsel GJ, Bossuyt PM. The diagnostic odds ratio: a single indicator of test performance. J Clin Epidemiol. 2003;56:1129-35.
LRs	>1 - diagnostic of interest	McGee²⁵25 McGee S. Simplifying likelihood ratios. J Gen Intern Med. 2002;17:647-50.
	0 and 1 - against the diagnosis of interest
	0 - less likely the disease
	=1 - lack diagnostic valeu
Sensitivity	80% excellent, 70-80% good, 60-69% fair, <60% poor	No consensus in this regard exists in the literature.
Specificity	90% excellent, 80-90% good, 70-79% fair, <70% poor	No consensus in this regard exists in the literature.
Youden's Index	Youden's Index values close to 1 indicate high accuracy; a value of zero is equivalent to uninformed guessing and indicates that a test has no diagnostic value.	Deeks et al.³⁸38 Deeks JJ, Bossuyt P, Gatsonis C, editors. Cochrane handbook for systematic reviews of diagnostic test accuracy version 1.0. The Cochrane Collaboration. 2010. Available from: http://srdta.cochrane.org/ http://srdta.cochrane.org/...

Author, year	Reason for exclusion
Dudik et al., 2016³⁹39 Dudik JM, Coyle JL, Ei-Jaroudi A, Sun MG, Sejdic E. A matched dual-tree wavelet denoising for tri-axial swallowing vibrations. Biomed Signal Process Control. 2016;27:112-21.	3
Dudik et al., 2015⁴⁰40 Dudik JM, Kurosu A, Coyle JL, Sejdic E. A comparative analysis of DBSCAN, K-means, and quadratic variation algorithms for automatic identification of swallows from swallowing accelerometry signals. Comput Biol Med. 2015;59:10-8.	3
Dudik et al., 2016⁴¹41 Dudik JM, Kurosu A, Coyle JL, Sejdic E. A statistical analysis of cervical auscultation signals from adults with unsafe airway protection. J Neuroeng Rehabil. 2016;13:7.	3
Frakking et al., 2016⁴²42 Frakking T, Chang A, O'Grady K, David M, Weir K. Aspirating and nonaspirating swallow sounds in children: a pilot study. Ann Otol Rhinol Laryngol. 2016;125:1001-9.	3
Frakking et al., 2016⁴³43 Frakking TT, Chang AB, O'Grady KF, David M, Weir KA. Reliability for detecting oropharyngeal aspiration in children using cervical auscultation. Int J Speech Lang Pathol. 2016;:1-9.	3
Golabbakhsh et al., 2014⁴⁴44 Golabbakhsh M, Rajaei A, Derakhshan M, Sadri S, Taheri M, Adibi P. Automated acoustic analysis in detection of spontaneous swallows in Parkinson's disease. Dysphagia. 2014;29:572-7.	3
Lee et al., 2006⁴⁵45 Lee J, Blain S, Casas M, Kenny D, Berall G, Chau T. A radial basis classifier for the automatic detection of aspiration in children with dysphagia. J Neuroeng Rehabil. 2006;3:14.	3
Mérey et al., 2012⁴⁶46 Merey C, Kushki A, Sejdic E, Berall G, Chau T. Quantitative classification of pediatric swallowing through accelerometry. J Neuroeng Rehabil. 2012;9:34.	3
Morinière et al., 2011⁴⁷47 Moriniere S, Boiron M, Brunereau L, Beutter P, Patat F. Pharyngeal swallowing sound profile assessed after partial and total laryngectomy. Dysphagia. 2011;26:366-73.	3
Movahedi et al., 2016⁴⁸48 Movahedi F, Kurosu A, Coyle JL, Perera S, Sejdic E. Anatomical directional dissimilarities in tri-axial swallowing accelerometry signals. IEEE Trans Neural Syst Rehabil Eng. 2017;25:477-558.	3
Nikjoo et al., 2011³²32 Nikjoo MS, Steele CM, Sejdic E, Chau T. Automatic discrimination between safe and unsafe swallowing using a reputation-based classifier. Biomed Eng Online. 2011;10:100.	3
Reddy et al., 2000⁴⁹49 Reddy NP, Katakam A, Gupta V, Unnikrishnan R, Narayanan J, Canilang EP. Measurements of acceleration during videofluorographic evaluation of dysphagic patients. Med Eng Phys. 2000;22:405-12.	3
Sejdic et al., 2014⁵⁰50 Sejdic E, Dudik JM, Kurosu A, Jestrovic I, Coyle JL. Understanding differences between healthy swallows and penetration-aspiration swallows via compressive sensing of tri-axial swallowing accelerometry signals. Proc SPIE Int Soc Opt Eng. 2014;:9190.	3
Seidic et al., 2013⁵¹51 Sejdic E, Steele CM, Chau T. Classification of penetration-aspiration versus healthy swallows using dual-axis swallowing accelerometry signals in dysphagic subjects. IEEE Trans Biomed Eng. 2013;60:1859-66.	3
Selley et al., 1994⁵²52 Selley WG, Ellis RE, Flack FC, Bayliss CR, Chir B, Pearce VR. The synchronization of respiration and swallow sounds with videofluoroscopy during swallowing. Dysphagia. 1994;9:162-7.	3
Spadotto et al., 2009⁵³53 Spadotto AA, Gatto AR, Guido RC, Montagnoli AN, Cola PC, Pereira JC, et al. Classification of normal swallowing and oropharyngeal dysphagia using wavelet. Appl Math Comput. 2009;207:75-82.	3
Spadotto et al., 2008⁵⁴54 Spadotto AA, Papa JP, Gatto AR, Cola PC, Pereira JC, Guido RC, et al. Denoising swallowing sound to improve the evaluator's qualitative analysis. Comput Electr Eng. 2008;34:148-53.	3
Steele et al., 2013⁵⁵55 Steele CM, Sejdić E, Chau T. Noninvasive detection of thin-liquid aspiration using dual-axis swallowing accelerometry. Dysphagia. 2013;28:105-12.	3
Stroud et al., 2002⁵⁶56 Stroud AE, Lawrie BW, Wiles CM. Inter- and intra-rater reliability of cervical auscultation to detect aspiration in patients with dysphagia. Clin Rehabil. 2002;16:640-5.	3
Tanaka et al., 2012⁵⁷57 Tanaka N, Nohara K, Okuno K, Kotani Y, Okazaki H, Matsumura M, et al. Development of a swallowing frequency meter using a laryngeal microphone. J Oral Rehabil. 2012;39:411-20.	3
Zoratto et al., 2010⁵⁸58 Zoratto DCB, Chau T, Steele CM. Hyolaryngeal excursion as the physiological source of swallowing accelerometry signals. Physiol Meas. 2010;31:843-55.	3
Lazareck et al., 2004⁵⁹59 Lazareck L, Moussavi Z. Classification of normal and dysphagic swallows by acoustical means. IEEE Trans Biomed Eng. 2004;51:2103-12.	3

	Item	Abdulmassih et al., 2013¹⁸18 David MAL, Alessandro L, Jennifer T, Douglas GA. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. PLoS Med. 2009;7:1-6.	Jayatilake et al., 2015¹⁹19 Whiting PF, Rutjes AW, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155:529-36.	Leslie et al., 2004²⁰20 Macaskill PGC, Deeks J, Harbord R, Takwoingi Y. Chapter 10: Analysing and presenting results. In: Collaboration C, editor. Cochrane handbook for systematic reviews of diagnostic test accuracy version 1.0. England: Birmingham; 2010.
Domain 1: Patient selection	Was a consecutive or random sample of patients enrolled?	N	N	N
	Was a case-control design avoided?	N	N	N
	Did the study avoid inappropriate exclusions?	Y	Y	Y
	Could the selection of patients have introduced bias?	H	H	H
	Concerns regarding applicability: Are there concern that the included patients and settings do not match the review question?	L	L	L
Domain 2: Index test	Were the index test results interpreted without knowledge of the results of the reference standard?	U	U	U
	If a threshold was used, was it prespecified?	Y	Y	Y
	Could the conduct or interpretation of the index test have introduced bias?	U	U	L
	Concerns regarding applicability: Are there concerns that the index test, its conduct, or its interpretation differ from the review question?	L	L	L
Domain 3: Reference standard	Is the reference standard likely to correctly classify the target condition?	Y	Y	Y
	Were the reference standard results interpreted without knowledge of the results of the index test?	U	U	U
	Could the reference standard, its conduct, or its interpretation have introduced bias?	L	L	L
	Concerns regarding applicability: Are there concerns that the target condition as defined by the reference standard does not match the question?	L	L	L
Domain 4: Flow and timing	Was there an appropriate interval between index test(s) and reference standard?	Y	Y	Y
	Did all patients receive the same reference standard?	Y	Y	Y
	Were all patients included in the analysis?	Y	N	N
	Could the patient flow have introduced bias?	L	L	L

[1] * Corresponding author. E-mails:karinnavm@hotmail.com, karinna@cb.ufrn.br (K.V. Taveira).

Brasil

Brasil

Abstract

Introduction:

Objective:

Methods:

Results:

Conclusion: