The effects of lingual training: a systematic review with meta-analysis

Fonseca, Nathalya de Faria; Motta, Andréa Rodrigues; Freitas, Fernanda Campos de; Nonato, Mariana Rezende; Francelino, Elton Mendes; Furlan, Renata Maria Moreira Moraes

doi:10.1590/2317-1782/20232021324en

Nathalya de Faria Fonseca

developing the research project

selecting

collecting

analyzing data

writing the manuscript

Universidade Federal de Minas Gerais - UFMG - Belo Horizonte (MG), Brasil.

https://orcid.org/0000-0003-0349-0415

Andréa Rodrigues Motta

supervised the study

critically reviewed the article

Universidade Federal de Minas Gerais - UFMG - Belo Horizonte (MG), Brasil.

https://orcid.org/0000-0002-1582-3785

Fernanda Campos de Freitas

developing the research project

selecting

collecting

analyzing data

writing the manuscript

Universidade Federal de Minas Gerais - UFMG - Belo Horizonte (MG), Brasil.

https://orcid.org/0000-0001-9186-6288

Mariana Rezende Nonato

developing the research project

selecting

collecting

analyzing data

writing the manuscript

Universidade Federal de Minas Gerais - UFMG - Belo Horizonte (MG), Brasil.

https://orcid.org/0000-0002-3530-5715

Elton Mendes Francelino

analyze the data

write the manuscript

Universidade Federal da Bahia - UFBA - Salvador (BA), Brasil.

https://orcid.org/0000-0002-9172-7373

Renata Maria Moreira Moraes Furlan

supervised the study and critically reviewed the article

Universidade Federal de Minas Gerais - UFMG - Belo Horizonte (MG), Brasil.

https://orcid.org/0000-0001-7588-9316

Conflict of interests: nothing to declare.

Correspondence address: Andréa Rodrigues Motta Departamento de Fonoaudiologia, Faculdade de Medicina, Universidade Federal de Minas Gerais - UFMG Avenida Alfredo Balena, 190, Santa Efigênia, Belo Horizonte (MG), Brasil, CEP: 30130-100. E-mail: andreamotta19@gmail.com

Author contributions

NFF, FCF, and MRN were responsible for developing the research project, selecting, collecting, and analyzing data, and writing the manuscript; EMF helped analyze the data and write the manuscript; RMMMF and ARM supervised the study and critically reviewed the article.

Source	Search strategy
VHL (BBO and LILACS)	(tongue OR lengua OR língua OR lingual) AND (“Muscle Strength” OR “Fuerza Muscular” OR “Força Muscular” OR “Physical Endurance” OR “Resistencia Física” OR “Resistência Física” OR “Força da Língua” OR “Tongue Strength” AND (“Resistance Training” OR “Entrenamiento de Resistencia” OR “Treinamento de Resistência” OR “Exercise Therapy” OR “Terapia por Ejercicio” OR “Terapia por Exercício” OR “Exercício Terapêutico” OR “Exercício de Reabilitação” OR rehabilitation OR rehabilitación OR reabilitação OR habilitação OR exercise OR “Ejercicio Físico” OR “Exercício Físico”) AND (db:(“LILACS” OR “BBO”))
CINAHL	(tongue OR lingual) AND (“muscle strength” OR “physical endurance” OR “tongue strength”) AND (“resistance training” OR “exercise therapy” OR rehabilitation OR exercise)
Cochrane	(tongue OR lingual) AND (“muscle strength” OR “physical endurance” OR “tongue strength”) AND (“resistance training” OR “exercise therapy” OR rehabilitation OR exercise)
EMBASE	tongue AND “muscle strength” OR “endurance” OR “tongue strength” AND “resistance training” OR rehabilitation OR exercise
PubMed	(tongue [MeSH Terms] OR lingual) AND (“muscle strength” [MeSH Terms] OR “physical endurance” [MeSH Terms] OR “tongue strength”) AND (“resistance training” [MeSH Terms] OR “exercise therapy” [MeSH Terms] OR rehabilitation [MeSH Terms] OR exercise [MeSH Terms])
Scopus	(ALL(tongue) OR ALL(lingual)) AND (ALL(“muscle strength”) OR ALL(“physical endurance”) OR ALL (“tongue strength”)) AND (ALL(“resistance training”) OR ALL (“exercise therapy”) OR ALL(rehabilitation) OR ALL(exercise)
Web of Science	ALL=((tongue OR lingual) AND (“muscle strength” OR “physical endurance” OR “tongue strength”) AND (“resistance training” OR “exercise therapy” OR rehabilitation OR exercise))

Author (year of publication), country	Sample	Description of exercises	Treatment frequency and duration	Measuring method and outcomes assessed	Tongue pressure	Results
Park et al. (2015)(¹⁵15 Park JS, Kim HJ, Oh DH. Effect of tongue strength training using the Iowa Oral Performance Instrument in stroke patients with dysphagia. J Phys Ther Sci. 2015;27(12):3631-4. http://dx.doi.org/10.1589/jpts.27.3631. PMid:26834320. http://dx.doi.org/10.1589/jpts.27.3631... )	27 adults with post-stroke dysphagia.	-Tongue pressure against the palate using IOPI (tip and dorsum), maintaining 80% of 1 MR for 2 s.	10 series with 5 repetitions (anterior + posterior)/day, 5x/week, for 4 weeks,	-IOPI (maximum anterior and posterior pressure)	-Anterior pressure:	-Increase in the anterior portion in EG and CG.
South Korea	EG = 15 individuals, m = 67.3±10.6 years, 6 men (exercises + dysphagia therapy).		minimum 30-s intervals between repetitions.	-Videofluoroscopy	EG: 18.9±6.7 kPa (before) and 20.7±6.6 kPa (after);	-Increase in the posterior portion in EG.
	CG = 14 individuals, m = 65.8±11.5 years, 7 men (dysphagia therapy)				CG: 22±5.7 kPa (before) and 22.9±5.4 kPa (after).	-Improved oral phase of swallowing in EG and CG and pharyngeal phase of swallowing in EG.
					-Posterior pressure:
					EG: 16.2±4.7 kPa (before) and 18.5±4.1 kPa: (after);
					CG: 17.3±4.3 kPa (before) and 17.7±4.36 kPa (after).
Byeon	48 adults with post-stroke dysphagia.	-Tongue protrusion, tongue lifting, and tongue lowering.	Exercises performed for 30 minutes a day, 5x/week, for 3 weeks.	-IOPI (lifting pressure and protrusion pressure, lip pressure and cheek pressure)	-Anterior tongue pressure	-Increased anterior tongue lifting pressure in EG and CG.
(2016)(¹⁶16 Byeon H. Effect of orofacial myofunctional exercise on the improvement of dysphagia patients’ orofacial muscle strength and diadochokinetic rate. J Phys Ther Sci. 2016;28(9):2611-4. http://dx.doi.org/10.1589/jpts.28.2611. PMid:27799705. http://dx.doi.org/10.1589/jpts.28.2611... )	EG = 23 individuals, m = 62.5±6.5 years, 8 men (exercises + tactile thermal stimulation).	-Massage on the cheeks and neck, lip closure and protrusion, cheek inflation and sucking, and tongue protrusion, lifting, and lowering.		-Praat (diadochokinesia)	EG: 20.8±13.2 kPa (before) and 26.8±14.3 kPa (after)	-Improved diadochokinesia in EG.
South Korea	CG = 25 individuals, m = 64.1±7.1 years, 6 men (tactile thermal stimulation).				CG: 18.5±11.5 kPa (before) and 21.5±10.8 kPa (after).
Kim et al. (2017)(¹⁷17 Kim HD, Choi JB, Yoo SJ, Chang MY, Lee SW, Park JS. Tongue-to-palate resistance training improves tongue strength and oropharyngeal swallowing function in subacute stroke survivors with dysphagia. J Oral Rehabil. 2017;44(1):59-64. http://dx.doi.org/10.1111/joor.12461. PMid:27883209. http://dx.doi.org/10.1111/joor.12461... )	35 individuals with post-stroke dysphagia	-Tongue counter-resistance exercise against the palate (anterior and posterior region).	30x/day, 5x/week, for 4 weeks.	-IOPI (maximum anterior and posterior tongue pressure)	-Anterior pressure	-Increased anterior and posterior tongue pressure in EG in 4 weeks.
South Korea	EG1 = 18 individuals, m = 62.2±11 years, 11 men (tongue force exercises + traditional dysphagia therapy).			-Videofluoroscopy (functional swallowing assessment - Videofluoroscopic Dysphagia Scale and Rosenbek’s penetration-aspiration scale)	EG: 32.7±10.8 kPa (before) and 41.9±9.5 kPa (after);	-Increased anterior and posterior tongue pressure in relation to CG.
	CG = 17 individuals, m = 59.3±10.2, 8 men (traditional dysphagia therapy).				GC: 29.6±10.4 kPa (before) and 32.5±10.2 kPa (after).	-Improved oral and pharyngeal phases of swallowing in EG and CG.
					-Posterior pressure	-Improved oral and pharyngeal phases of swallowing EG in relation to CG.
					EG: 28.1±7.6 kPa (before) and 39.1±7.8 kPa (after)	-Improvement on the penetration-aspiration scale in EG and CG.
					CG: 26.6±9.1 kPa (before) and 31.4±9.7 kPa (after).
Byeon	21 individuals with post-stroke dysarthria	EG and CG: pressing the IOPI bulb against the palate, exerting 50%, 75%, and 100% of the maximum tongue force; 4 series with 5 repetitions.	30min/day, 5x/week, for 4 weeks.	-IOPI (maximum tongue pressure);	-Anterior pressure	-EG had greater maximum tongue force than CG.
(2018)(¹⁸18 Byeon H. Is the combined application of tongue pressure training and tongue base exercise more effective in improving the strength of tongue and lips in Korean patients with flaccid dysarthria? Indian J Public Health. 2018;9(11):1041-7. http://dx.doi.org/10.5958/0976-5506.2018.01594.2. http://dx.doi.org/10.5958/0976-5506.2018... )	EG = 10 individuals, m = 65.85±9.23 years (tongue pressure exercises + tongue exercises).	EG: (i) Lifting the tip of the tongue and sustaining it for 5 s; (ii) lifting the tip of the tongue against a spatula and sustaining it for 5 s; (iii) lateralizing the tongue and sustaining it for 5 s to the right and 5 s to the left.		-Percentage of correctly articulated consonants.	EG: 10.7±9.8 kPa (before) and 20.8±16.9 kPa (after);	-No differences were found in the percentage of correctly articulated consonants between EG and CG.
South Korea	CG = 11 individuals, m = 67.03±7.60 (tongue pressure exercises)	(iv) lateralizing the tongue against a spatula and sustaining it for 5 s to the right and 5 s to the left; (v) protruding the tongue for 5 s and protruding the tongue against a spatula for 5 s.			CG: 11.4±8.1 kPa (before) and 17.9±15.1 (after).
Hsiang et al. (2019)(²⁵25 Hsiang CC, Chen AW, Chen CH, Chen MK. Early postoperative oral exercise improves swallowing function among patients with oral cavity cancer: a randomized controlled trial. Ear Nose Throat J. 2019;98(6):E73-80. http://dx.doi.org/10.1177/0145561319839822. PMid:31088304. http://dx.doi.org/10.1177/01455613198398... )	50 adults with oral cavity and/or oropharyngeal cancer submitted to tumor resection surgery during a recent post-operational period (48 men, m = 56.2±8.8 years).	-Tongue, lip, and mandible mobility exercises: Sustaining maximum structure extension for 1-2 s, then relaxing.	Exercises performed 10x/session,	-Videofluoroscopy (Rosenbek’s penetration-aspiration scale and oral cavity and pharyngeal residues)	Not assessed	-Improvement on the penetration-aspiration scale in EG.
China	EG = 25 (exercises)	-Tongue resistance exercises: counter-resistance against a spatula for 5 s.	3 sessions/day, for 12 weeks.			-Decreased amounts of nectar, honey, and pudding consistency residues in EG.
	CG = 25 (changes in body posture and food consistency)
Park et al. (2019)(¹⁹19 Park HS, Oh DH, Yoon T, Park JS. Effect of effortful swallowing training on tongue strength and oropharyngeal swallowing function in stroke patients with dysphagia: a double-blind, randomized controlled trial. Int J Lang Commun Disord. 2019;54(3):479-84. http://dx.doi.org/10.1111/1460-6984.12453. PMid:30693627. http://dx.doi.org/10.1111/1460-6984.1245... )	24 adults with post-stroke dysphagia.	-Effortful swallowing training: pressing the tongue firmly against the palate while contracting the neck muscle and swallowing as strongly as possible.	Exercises performed 10x/session,	-IOPI (maximum anterior and posterior pressure)	-Anterior pressure:	-Increased anterior pressure in EG and CG.
South Korea	EG = 12 individuals, m = 66.5±9.5 years, 6 men (effortful swallowing + dysphagia therapy).		3 sessions/day, for 4 weeks.	-Videofluoroscopy (functional swallowing assessment - (Videofluoroscopic Dysphagia Scale)	EG: 20.8±4.3 kPa (before) and 27.6±4.3 kPa (after);	-Increased posterior pressure in EG and CG.
	CG = 12 individuals, m = 64.8±11.2 years, 5 men (dysphagia therapy)				CG: 21.2±5.8 kPa (before) and 23.1±5.4 kPa (after). -Posterior pressure:	-Improved oral and pharyngeal phases of swallowing in EG and CG.
					EG: 16.6±5.0 kPa (before) and 23.2±5.4 kPa (after);
					CG: 16.7±4.4 kPa (before) and 18.2±4.5 kPa (after).

Author (year of publication), country	Sample	Description of exercises	Treatment frequency and duration	Measuring method and outcomes assessed	Tongue pressure	Results
Author (year of publication), country	Sample	Description of exercises	Treatment frequency and duration	Measuring method and outcomes assessed	Tongue pressure	Results	Lazarus et al. (2003)(²³23 Lazarus C, Logemann JA, Huang CF, Rademaker AW. Effects of two types of tongue strengthening exercises in young normals. Folia Phoniatr Logop. 2003;55(4):199-205. http://dx.doi.org/10.1159/000071019. PMid:12802092. http://dx.doi.org/10.1159/000071019... ) United States	31 healthy individuals, m = 26 years.	-Pressing the tongue against a spatula or the IOPI bulb in the left and right directions, protrusion, and lifting, as strong as possible for 2 s.	10 repetitions, 5x/day, 5x/week, for 4 weeks.	-IOPI (maximum tongue pressure and resistance).	-Maximum anterior pressure:	-Increased maximum tongue pressure in EG1 and EG2.
EG1 = 10 individuals, 2 men (strength exercise using a spatula).	EG1: 63.9±2.2 kPa (before) and 72.1±2.1 kPa (after);	-Increased tongue resistance in EG1 and EG2.
EG2 = 10 individuals, 1 man (strength exercise using IOPI).	EG2: 64.8±3.0 kPa (before) and 74.0±2.4 kPa (after);	-Increased maximum tongue pressure when comparing the combined EG1 and EG2 results with CG.
CG = 10 individuals, 5 men (no intervention)	CG: 69.8±5.6 kPa (before) and 71.2±5.4 (after).
Clark (2012)(²⁴24 Clark HM. Specificity of training in the lingual musculature. J Speech Lang Hear Res. 2012;55(2):657-67. http://dx.doi.org/10.1044/1092-4388(2011/11-0045). PMid:22215031. http://dx.doi.org/10.1044/1092-4388(2011... )	25 individuals, m = 29.8 years; 3 men	EG1: pressing the tongue against the IOPI bulb on the palate with maximum strength.	1x/day, 3x/week, for 4 weeks	-IOPI (anterior tongue lifting pressure, resistance, power, and speed).	EG1: 65.8 kPa (before) and 82.6 kPa (after);	-Increased pressure in EG1, isotonic resistance in EG2, and power in EG3.
United States	EG1 = 5 individuals (strength training).	EG2: pressing against the IOPI bulb at 50% of the maximum strength as many times as possible (isotonic) and pressing the bulb at 50% of the maximum strength for as long as possible (isometric).			EG2: 65.6±15.2 kPa (before) and 73.0±18.4 kPa (after);	-Neither isometric resistance in EG2 nor speed in EG4 increased.
	EG2 = 5 individuals (resistance training).	EG3: repeating the phoneme /t/ as fast as possible, pushing the bulb at 5% of the maximum strength for 10 s.	EG1: 5 series of 5 repetitions.		EG3: 60.2±18.0 kPa (before) and 66.6±17.0 kPa (after);
	EG3 = 5 individuals (power training).	EG4: repeating the phoneme /t/ as fast as possible for 10 s.	EG2: 5 series with 5% of the maximum number of repetitions.		EG4: 72.8±14.7 kPa (before) and 80.4±20.1 kPa (after);
	EG4 = 5 individuals (speed training).		EG3: 5 series of 10 repetitions.		CG: 66.8±13.2 kPa (before) and 73.6±10.1 kPa (after).
	CG = 5 individuals (no intervention).		EG4: five 10-s series.
Park et al. (2019)(²⁰20 Park JS, Hwang NK, Kim HH, Choi JB, Chang MY, Jung YJ. Effects of lingual strength training on oropharyngeal muscles in South Korean adults. J Oral Rehabil. 2019;46(11):1036-41. http://dx.doi.org/10.1111/joor.12835. PMid:31206763. http://dx.doi.org/10.1111/joor.12835... )	30 healthy adults	-Tongue pressure against the palate with maximum strength (isotonic and isometric).	The isotonic exercise was performed 30x (2 s) and the isometric one 3x (10 s), 1x/day, 5x/week, for 6 weeks.	-IOPI (tongue pressure).	-Anterior pressure	-Increased tongue pressure in GE. -Increased tongue, mylohyoid, and digastric thickness in EG.
South Korea	EG = 15 individuals, m = 24.5±5.3 years, 8 men (exercise).			-Ultrasound (tongue, mylohyoid, and digastric thickness).	EG: 52.5±4.4 kPa (before) and 57.7±5.2 kPa (after);	-Increased tongue thickness in CG.
	CG = 15 individuals, m = 25.1±4.2 years, 7 men (no intervention).				CG: 53.8±3.0 kPa (before) and 54.7±1.95 kPa (after).

Author (year of publication), country	Sample	Description of the exercises	Treatment frequency and duration	Measuring method and outcomes assessed	Tongue pressure	Results
Van den Steen et al. (2019)(²⁶26 Van den Steen L, Vanderwegen J, Guns C, Elen R, De Bodt M, Van Nuffelen G. Tongue-strengthening exercises in healthy older adults: does exercise load matter? A randomized controlled trial. Dysphagia. 2019;34(3):315-24. http://dx.doi.org/10.1007/s00455-018-9940-5. PMid:30209561. http://dx.doi.org/10.1007/s00455-018-994... )	60 Older adults	-Pressing the IOPI bulb against the palate in the anterior and posterior positions:	60x anterior and 60x posterior, divided into 24 series of 5 repetitions with 30-s rest between them, for 3 non-consecutive days a week, for 8 weeks.	-IOPI (maximum anterior and posterior pressure) at the beginning of the study, after 4 and 8 weeks of training.	-Maximum anterior pressure:	-All three experimental groups had increased pressure in 4 weeks and 8 weeks.
Belgium	EG1 = 15 individuals, m = 79 years, 7 men	EG1: at 100% of 1 MR.			EG1: 36.9 ± 9.1 kPa (before) and 59.4±12.6 kPa (8 weeks)	-Greater maximum pressure in all EG than in CG.
	EG2 = 16 individuals, m = 81 years, 7 men	EG2: at 80% of 1 MR.			EG2: 34.1 ± 8.0 kPa (before) and 54.7±7.7 kPa (8 weeks)
	EG3 = 16 individuals, m = 77 years, 3 men	EG3: at 60% of 1 MR.			EG3: 35.3 ± 6.8 kPa (before) and 53.6±7.31 kPa (8 weeks)
	CG = 13 individuals	CG: pressing the IOPI bulb between the lips.			CG: 39.2 ± 9.9 kPa (before) and 44.5kPa± 11.7 (8 weeks)
					-Maximum posterior pressure:
					EG1: 30.2±8.3 kPa (before) and 52.7±12.3 kPa (8 weeks)
					EG2: 34.0±7.6 kPa (before) and 51.1±9.9 kPa (8 weeks)
					EG3: 32.8±4.4 kPa (before) and 50.3±8.1 kPa (8 weeks)
					CG: 34.6±8.7 kPa (before) and 38.9±12.3 kPa (8 weeks)
Park et al. (2019)(²¹21 Park JS, Lee SH, Jung SH, Choi JB, Jung YJ. Tongue strengthening exercise is effective in improving the oropharyngeal muscles associated with swallowing in community-dwelling older adults in South Korea: a randomized trial. Medicine. 2019;98(40):e17304. http://dx.doi.org/10.1097/MD.0000000000017304. PMid:31577721. http://dx.doi.org/10.1097/MD.00000000000... )	40 older adults.	-Pressing the tongue against the palate at 70% of 1 MR (isotonic and isometric).	The isotonic exercise was performed 30x and the isometric one 3x (30 s), 3x/day. The training duration was not specified.	-IOPI (tongue pressure)	-Anterior pressure:	-Increased tongue pressure in EG and tongue, mylohyoid, and digastric thickness.
South Korea	EG = 20 individuals, m = 69.5±4.3; 10 men (exercise);			-Ultrasound (tongue, mylohyoid, and digastric thickness).	EG: 37.1±3.5 kPa (before) and 43.9±4.9 kPa (after);	-Unchanged tongue pressure and thickness in CG.
	CG = 20 individuals, m = 68.4±3.9 years; 11 men (no intervention).				CG: 36.6±3.3 kPa (before) and 37.1±3.4 kPa (after).
Lee et al. (2020)(²²22 Lee KH, Jung ES, Choi YY. Effects of lingual exercises on oral muscle strength and salivary flow rate in elderly adults: a randomized clinical trial. Geriatr Gerontol Int. 2020;20(7):697-703. http://dx.doi.org/10.1111/ggi.13944. PMid:32489001. http://dx.doi.org/10.1111/ggi.13944... )	74 older adults (m = 75 years)	EG1: (i) Swallowing saliva without sticking the tongue out of the mouth; (ii) swallowing saliva strongly without sticking the tongue out of the mouth; (iii) swallowing saliva with about one third of the tongue out of the mouth; and (iv) swallowing saliva with about two thirds of the tongue out of the mouth. Three repetitions each.	3x/day, 3x/week for 8 weeks.	-IOPI (anterior and posterior tongue pressure and lip pressure)	-Anterior pressure:	-Increased anterior and posterior tongue pressure in EG1.
South Korea	EG1 = 30 individuals, 3 men (swallowing with tongue control).	EG2: pressing the IOPI bulb between the tongue and the hard palate. 30 repetitions.		-Salivary flow rate	EG1: 34.3±10.1 kPa (before) and 38.5±13.4 kPa (after):	-Increased anterior tongue pressure in EG2.
	EG2 = 22 individuals, 3 men (resistance training with tongue pressure).			-Score of the Oral Health Impact Profile-14.	EG2: 40.6±11.5 kPa (before) and 45.5±11.0 (after);	-Increased salivary flow rate in EG1 and EG2.
	CG = 22 individuals, 6 men (no intervention).				CG: 39.1±12.9 kPa (before) and 38.4±11.1 kPa (after).	-Absence of impact in Oral Health Impact Profile-14 in the groups.
					-Posterior pressure:
					EG1: 33.8±13.8 kPa (before) and 38.1±15.0 kPa (after);
					EG2: 41.4±11.2 kPa (before) and 45.1±9.7 (after);
					CG: 35.6±15.3 kPa (before) and 38.8±12.8 kPa (after).

Author (year of publication), country	Sample	Description of the exercises	Treatment frequency and duration	Measuring method and outcomes assessed	Tongue pressure	Results
Ieto et al. (2015)(¹³13 Ieto V, Kayamori F, Montes MI, Hirata RP, Gregório MG, Alencar AM, et al. Effects of oropharyngeal exercises on snoring: a randomized trial. Chest. 2015;148(3):683-91. http://dx.doi.org/10.1378/chest.14-2953. PMid:25950418. http://dx.doi.org/10.1378/chest.14-2953... )	39 individuals with primary snoring or mild to moderate obstructive sleep apnea.	-Pressing the tip of the tongue against the hard palate and sliding it backward.	20 repetitions of each exercise, 3x/day, for 3 months.	-Pittsburgh Sleep Quality Index.	Not assessed	-Improved sleep quality index in EG.
Brazil	EG = 19 individuals, m = 48±14 years, 11 men (oropharyngeal exercises + nasal rinsing).	-Sucking the tongue completely against the palate.		-Epworth Sleepiness Scale		-Improved personal sensation of the frequency of snoring in EG and CG.
	CG = 20 individuals, m = 45±13 years, 11 men (nasal dilator + nasal rinsing + breathing exercises)	-Lowering the tongue dorsum while keeping its tip in touch with the lower incisor.		-Snoring frequency and intensity sensation.		-Improved partner sensation of the frequency and intensity of snoring in EG.
		-Training with alternated bilateral mastication and swallowing with the tip of the tongue on the palate.		-Polysomnography		-Polysomnography with no significant changes.
		-Other exercises for the soft palate and buccinator.
Diaféria et al. (2017)(¹⁴14 Diaféria G, Santos-Silva R, Truksinas E, Haddad FLM, Santos R, Bommarito S, et al. Myofunctional therapy improves adherence to continuous positive airway pressure treatment. Sleep Breath. 2017;21(2):387-95. http://dx.doi.org/10.1007/s11325-016-1429-6. PMid:27913971. http://dx.doi.org/10.1007/s11325-016-142... )	100 individuals with obstructive sleep apnea, m = 48.1±11.2 years, all of them males	-Tongue exercises:	3x/day, 3x/week, for 20 minutes, for 3 months.	-Epworth Sleepiness Scale.	Not assessed	-Improved Epworth Scale in EG1, EG2, and EG3 at the end of the treatment and compared with CG.
Brazil	EG1= 27 individuals (myofunctional therapy).	(i) Brushing the upper and lateral parts of the tongue, with the tongue on the floor of the mouth (5x each movement); (ii) pressing the tip of the tongue against the palate and sliding it backward (20x);		-Polysomnography (obstructive sleep apnea index, number of nocturnal wakes, and peripheral oxygen saturation).		-Improved snoring intensity and frequency in EG1, EG2, and EG3 at the end of the treatment and compared with CG.
	EG2 = 27 individuals (CPAP).	(iii) sucking the tongue completely against the palate (20x); (iv) tongue rotation in the vestibule (10x clockwise and 10x counterclockwise); (v) lowering the tongue dorsum (20x).				-Improved polysomnography in EG2 and EG3 at the beginning of the treatment and compared with CG.
	EG3 = 22 individuals (CPAP + myofunctional therapy).	-Exercises for the soft palate and buccinator.				-Improved apnea index and number of wakes in EG1 compared with CG.
	CG = 24 individuals (placebo myofunctional therapy).	-Training with mastication, swallowing, suction, and breathing.

Author	Q1	Q2	Q3	Q4	Q5	Q6	Q7	Q8	Q9	Q10	Q11	Q12	Q13	TOTAL
Lazarus et al.(²³23 Lazarus C, Logemann JA, Huang CF, Rademaker AW. Effects of two types of tongue strengthening exercises in young normals. Folia Phoniatr Logop. 2003;55(4):199-205. http://dx.doi.org/10.1159/000071019. PMid:12802092. http://dx.doi.org/10.1159/000071019... )	Unclear	Unclear	Yes	No	NA	Unclear	Yes	No	Unclear	Yes	Yes	Yes	Yes	6
Clark(²⁴24 Clark HM. Specificity of training in the lingual musculature. J Speech Lang Hear Res. 2012;55(2):657-67. http://dx.doi.org/10.1044/1092-4388(2011/11-0045). PMid:22215031. http://dx.doi.org/10.1044/1092-4388(2011... )	Yes	Unclear	Yes	No	NA	Unclear	Yes	Yes	Yes	Yes	Yes	Yes	Yes	9
Ieto et al.(¹³13 Ieto V, Kayamori F, Montes MI, Hirata RP, Gregório MG, Alencar AM, et al. Effects of oropharyngeal exercises on snoring: a randomized trial. Chest. 2015;148(3):683-91. http://dx.doi.org/10.1378/chest.14-2953. PMid:25950418. http://dx.doi.org/10.1378/chest.14-2953... )	Unclear	Unclear	Yes	No	NA	Yes	Yes	Yes	Yes	Yes	Yes	Yes	Yes	9
Park et al.(¹⁵15 Park JS, Kim HJ, Oh DH. Effect of tongue strength training using the Iowa Oral Performance Instrument in stroke patients with dysphagia. J Phys Ther Sci. 2015;27(12):3631-4. http://dx.doi.org/10.1589/jpts.27.3631. PMid:26834320. http://dx.doi.org/10.1589/jpts.27.3631... )	Yes	Yes	Yes	No	NA	Yes	Yes	No	Unclear	Yes	Yes	Yes	Yes	9
Byeon(¹⁶16 Byeon H. Effect of orofacial myofunctional exercise on the improvement of dysphagia patients’ orofacial muscle strength and diadochokinetic rate. J Phys Ther Sci. 2016;28(9):2611-4. http://dx.doi.org/10.1589/jpts.28.2611. PMid:27799705. http://dx.doi.org/10.1589/jpts.28.2611... )	Yes	Unclear	Yes	No	NA	Unclear	Yes	No	Unclear	Yes	Yes	Yes	Yes	7
Diaféria et al.(¹⁴14 Diaféria G, Santos-Silva R, Truksinas E, Haddad FLM, Santos R, Bommarito S, et al. Myofunctional therapy improves adherence to continuous positive airway pressure treatment. Sleep Breath. 2017;21(2):387-95. http://dx.doi.org/10.1007/s11325-016-1429-6. PMid:27913971. http://dx.doi.org/10.1007/s11325-016-142... )	Unclear	Unclear	Yes	No	NA	Yes	No	Yes	No	Yes	No	Yes	Yes	6
Kim et al.(¹⁷17 Kim HD, Choi JB, Yoo SJ, Chang MY, Lee SW, Park JS. Tongue-to-palate resistance training improves tongue strength and oropharyngeal swallowing function in subacute stroke survivors with dysphagia. J Oral Rehabil. 2017;44(1):59-64. http://dx.doi.org/10.1111/joor.12461. PMid:27883209. http://dx.doi.org/10.1111/joor.12461... )	Yes	Unclear	Yes	No	NA	Unclear	Yes	Yes	Yes	Yes	Yes	Yes	Yes	9
Byeon(¹⁸18 Byeon H. Is the combined application of tongue pressure training and tongue base exercise more effective in improving the strength of tongue and lips in Korean patients with flaccid dysarthria? Indian J Public Health. 2018;9(11):1041-7. http://dx.doi.org/10.5958/0976-5506.2018.01594.2. http://dx.doi.org/10.5958/0976-5506.2018... )	Unclear	Unclear	Yes	No	NA	Unclear	Yes	No	Unclear	Yes	Yes	Yes	Yes	6
Van den Steen et al.(²⁶26 Van den Steen L, Vanderwegen J, Guns C, Elen R, De Bodt M, Van Nuffelen G. Tongue-strengthening exercises in healthy older adults: does exercise load matter? A randomized controlled trial. Dysphagia. 2019;34(3):315-24. http://dx.doi.org/10.1007/s00455-018-9940-5. PMid:30209561. http://dx.doi.org/10.1007/s00455-018-994... )	Unclear	Unclear	Yes	No	NA	Unclear	Yes	Yes	Yes	Yes	Yes	Yes	Yes	8
Hsiang et al.(²⁵25 Hsiang CC, Chen AW, Chen CH, Chen MK. Early postoperative oral exercise improves swallowing function among patients with oral cavity cancer: a randomized controlled trial. Ear Nose Throat J. 2019;98(6):E73-80. http://dx.doi.org/10.1177/0145561319839822. PMid:31088304. http://dx.doi.org/10.1177/01455613198398... )	Yes	Unclear	Yes	No	NA	Yes	Yes	Yes	Yes	Yes	No	Yes	Yes	9
Park et al.(¹⁹19 Park HS, Oh DH, Yoon T, Park JS. Effect of effortful swallowing training on tongue strength and oropharyngeal swallowing function in stroke patients with dysphagia: a double-blind, randomized controlled trial. Int J Lang Commun Disord. 2019;54(3):479-84. http://dx.doi.org/10.1111/1460-6984.12453. PMid:30693627. http://dx.doi.org/10.1111/1460-6984.1245... )	Yes	Yes	Yes	Yes	NA	Yes	Yes	Yes	No	Yes	Yes	Yes	Yes	11
Park et al.(²⁰20 Park JS, Hwang NK, Kim HH, Choi JB, Chang MY, Jung YJ. Effects of lingual strength training on oropharyngeal muscles in South Korean adults. J Oral Rehabil. 2019;46(11):1036-41. http://dx.doi.org/10.1111/joor.12835. PMid:31206763. http://dx.doi.org/10.1111/joor.12835... )	Yes	Unclear	Yes	No	NA	Yes	Yes	Unclear	Unclear	Yes	Yes	Yes	Yes	8
Park et al.(²¹21 Park JS, Lee SH, Jung SH, Choi JB, Jung YJ. Tongue strengthening exercise is effective in improving the oropharyngeal muscles associated with swallowing in community-dwelling older adults in South Korea: a randomized trial. Medicine. 2019;98(40):e17304. http://dx.doi.org/10.1097/MD.0000000000017304. PMid:31577721. http://dx.doi.org/10.1097/MD.00000000000... )	Unclear	Unclear	Yes	No	NA	Unclear	Yes	Yes	Yes	Yes	Yes	Yes	Yes	8
Lee et al.(²²22 Lee KH, Jung ES, Choi YY. Effects of lingual exercises on oral muscle strength and salivary flow rate in elderly adults: a randomized clinical trial. Geriatr Gerontol Int. 2020;20(7):697-703. http://dx.doi.org/10.1111/ggi.13944. PMid:32489001. http://dx.doi.org/10.1111/ggi.13944... )	Unclear	Unclear	Yes	No	NA	Unclear	Yes	Yes	No	Yes	Yes	Yes	Yes	7

Myotherapy exercises compared with the absence of exercises in individuals older than 18 years.
Assessment of the certainty							Number of patients		Effect		Certainty	Importance
Number of studies	Study design	Risk of bias	Inconsistency	Indirect evidence	Imprecision	Other considerations	Myotherapy exercises	Absence of exercises	Relative (95% CI)	Absolute (95% CI)	Certainty	Importance
Anterior tongue pressure (follow-up ranging from 3 to 8 weeks; assessed with IOPI)
11	Randomized clinical trials	Very severe^a a Studies with moderate and low methodological quality contribute to more than 50% of the weight in the meta-analysis for this outcome;	Not severe	Not severe	Not severe	None	252	227	-	DM 6.05 kPa higher (4.39 higher to 7.71 lower)	⨁⨁◯◯ Low	Myotherapy exercises increase anterior tongue pressure. However, the studies analyzed had methodological biases.
Posterior tongue pressure (follow-up ranging from 4 to 8 weeks; assessed with IOPI)
5	Randomized clinical trials	Not severe	Not severe	Severe^b b There was an absence of studies in adults assessing this outcome. All studies were conducted in older adults;	Severe^c c Few participants had this outcome assessed	None	137	126	-	DM 5.45 kPa higher (2.8 higher to 8.11 lower)	⨁⨁◯◯ Low	Myotherapy exercises increase posterior tongue pressure. However, the outcome was not assessed in adults, and there were few participants.

[1] Conflict of interests: nothing to declare.

Brasil

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The effects of lingual training: a systematic review with meta-analysis

ABSTRACT

Purpose

Research strategies

Selection criteria

Data analysis

Results

Conclusion