Ultrasound Assessment of Tongue Characteristics in Adolescents With Obesity and Obstructive Sleep Disorders

Standardised Ultrasound Assessment of Tongue Characteristics in Adolescents With Obesity and Obstructive Sleep Disordered Breathing: a Research Protocol

Obstructive sleep-disordered breathing, including obstructive sleep apnea (OSA), represents a significant yet underdiagnosed condition in the pediatric population, particularly among adolescents with obesity. The tongue is a central anatomical contributor to upper airway collapsibility; however, its biomechanical properties have been investigated almost exclusively in adult populations, leaving a critical gap in knowledge regarding younger individuals.

This study aims to assess tongue biomechanical and echographic characteristics using quantitative ultrasound modalities - shear-wave elastography (SWE), acoustic attenuation, and echo intensity - in adolescents aged 12 to 18 years with obesity and obstructive sleep disorders. The study adopts a mixed design combining (1) an observational cross-sectional comparison between participants with obesity and OSDB and age- and sex-matched healthy controls at baseline, and (2) a prospective longitudinal cohort component evaluating changes in tongue ultrasound characteristics over the course of a 30-week multidisciplinary inpatient weight-loss program delivered as standard care at the Zeepreventorium (De Haan, Belgium). An additionnal methodological objective consists in determining intra-rater and inter-rater reliability of the ultrasound acquisition protocol providing a reproducible framework for future studies.

Study Overview

• Status: Not yet recruiting
• Conditions: Pediatric Obesity; Obstructive Sleep Disordered Breathing; Obesity & Overweight Sleep
• Intervention / Treatment: Device: Submental ultrasound

Detailed Description

Scientific Background and Rationale Amongst obstructive sleep disorders, Obstructive sleep apnea (OSA) is characterized by repetitive complete (apnea) or partial (hypopnea) collapse of the upper airway during sleep. Upper airway collapsibility in OSA results from the interaction of multiple contributing mechanisms, including craniofacial morphology (retrognathia, maxillary constriction, reduced posterior airway space), adenotonsillar hypertrophy - a predominant anatomical risk factor in the pediatric population -, obesity-related peripharyngeal fat deposition, neuromuscular control deficits of upper airway dilator muscles, and environmental exposures such as prenatal or passive tobacco smoke exposure, associated with increased upper airway inflammation and altered respiratory control.

Among the anatomical structures implicated in upper airway collapsibility, the tongue plays a central role as the largest muscular structure of the oropharynx. Morphological and biomechanical alterations (incl. increased volume, fat infiltration at the base, posterior positioning, and modified tissue stiffness) have been identified as relevant contributors to airway obstruction and are increasingly investigated as potential screening markers.

In the pediatric population, OSA remains substantially underdiagnosed. Access to polysomnography is limited, parents seldom spontaneously report nocturnal symptoms, and prevalence estimates vary widely in the literature (1.2% to over 60% in children with obesity), partly due to heterogeneous diagnostic criteria. This epidemiological uncertainty underscores the need for accessible, non-invasive tools capable of characterizing tongue biomechanical properties in younger populations - a gap that the present study directly addresses.

Ultrasound is non-invasive, non-ionizing, widely accessible, and well tolerated, including in adolescents. Existing studies applying these modalities to the tongue in OSA have been conducted exclusively in adult populations and report heterogeneous, sometimes contradictory findings. Methodological variability in acquisition parameters, probe positioning, and region-of-interest definition substantially limits reproducibility and inter-study comparability. No study to date has applied this multimodal quantitative ultrasound approach to adolescents with obesity and obstructive sleep-disordered breathing, nor examined the longitudinal trajectory of these parameters in response to a structured weight-loss intervention. The present study is therefore the first to address this population and this clinical question.

Tongue morphology and tongue fat in patients suffering from OSA have been assessed several times with ultrasound, a non-invasive, widely accessible imaging modality that provides real-time visualization of tissues and is generally well tolerated, with minimal to no associated discomfort. Ultrasound echo intensity has been validated with MRI to estimate tongue fat percentage. Advanced ultrasound modalities, such as shear wave elastography (SWE) and attenuation imaging (AI), provide quantitative measures of tissue stiffness and its attenuation properties, respectively Existing studies on tongue SWE and echo intensity (EI) have been conducted exclusively in adults and report heterogeneous, and sometimes contradictory, findings in patients suffering from OSA. Raw data in EI values would increase in the case of high lipidic impregnation or fibrous accumulation and decrease when the amount of muscle is higher, but the results are still variable depending on the location. Methodological variability in acquisition parameters, probe positioning, region-of-interest definition, and data analysis substantially limit reproducibility and comparability. Arbitrary region-of-interest sizing that does not account for individual tongue morphology may further introduce systematic bias.

Another gap in current research is the limited focus on younger populations. While studies have primarily targeted middle-aged and older adults due to the higher prevalence of OSA in these groups, the biomechanical properties of the tongue may differ significantly in younger individuals, due to growth and hormonal factors. In particular, heterogeneous distribution of elasticity values between anterior and posterior regions of the tongue indicate that there is a need for a better understanding The objectives of this study and anticipated new evidence are as follows below. Primary objective: to compare tongue biomechanical properties, assessed using shear-wave elastography and quantitative ultrasound, between children and adolescents with obesity and obstructive sleep disorders and age-matched healthy controls.

Secondary objectives: (1) to assess longitudinal changes in tongue echographic characteristics over the course of a 30-week multidisciplinary weight-loss program delivered as part of standard care and (2) to evaluate the influence of anthropometric parameters, sex, and pubertal status on these measurements.

Methodological objective: to determine the intra-rater and inter-rater reliability of ultrasound-based tongue measurements, thereby providing a reproducible framework for future clinical and comparative studies.

• Study Type: Interventional
• Enrollment (Estimated): 80
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Frederic Paillaugue, MSc PT; Phone Number: +32485952930; Email: frederic.paillaugue@vub.be

Study Locations

• Belgium
  • Brussels, Belgium, 1090
    • KidZ Health Castle - Universitair Ziekenhuis Brussel Brussels - Health Campus Avenue du Laerbeek 101 1090 Jette
    • Contact: Frederic Paillaugue, MSc PT; Phone Number: +32485952930; Email: frederic.paillaugue@vub.be
    • Contact: Inge Gies, MD; Phone Number: +324774111; Email: inge.gies@uzbrussel.be
    • Principal Investigator: Steven Provyn, Prof PhD
  • De Haan, Belgium, 8420
    • Zeepreventorium, Koninklijke Baan 5, 8420 De Haan
    • Contact: Frederic Paillaugue, MSc PT; Phone Number: +32485952930
    • Principal Investigator: Steven Provyn, Prof PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• Aged 12-18 years
• Already enrolled in Zeepreventorium weight-loss program as Standard Care Diagnosed Obstructive Sleep Apnea (AHI ≥ 1)1 or any Obstructive sleep disordered breathing detected by any of the specific sleep questionnaire (OSA-18, ESS, SSS-Ad, PDSS)

Exclusion Criteria:

• Any other orthopedic, traumatic, or rheumatologic condition affecting the cervicocephalic region
• Syndromic or neuromuscular disorders
• Cognitive impairment limiting compliance with study procedures
• Inability to provide informed consent
• Self-reported alcohol or recreational drug consumption within 48 hours preceding the experimental session

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Non-Randomized
• Interventional Model: Crossover Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Study group; Adolescents (12-18 y.o.) with obesity and sleep-disordered breathing, recruited at the Zeepreventorium de Haan and at the KidZ Health Castle UZ-VUB. The intervention will consist of a submental ultrasound examination - a pain-free, non-ionizing, and non-invasive imaging procedure - aimed at quantifying tongue biomechanical properties, complemented by the collection of descriptive and anthropometric measures including standing height, body weight, impedance analysis, and neck circumference.	Device: Submental ultrasound; Tongue ultrasound via a submental approach. This non-invasive, pain-free and non-radiating protocol will study both morphological and dynamic characteristics of the tongue. Ultrasonographic assessment will be performed with participants in a resting, supine position and ultrasound gel will be used to optimise submental probe contact.
Active Comparator: Control group; A control group of healthy participants (without obesity nor sleep disorders), matched for gender and age, will be recruited from among the researchers' acquaintances. The intervention will be the same, consisting of a submental ultrasound examination - a pain-free, non-ionizing, and non-invasive imaging procedure - aimed at quantifying tongue biomechanical properties, complemented by the collection of descriptive and anthropometric measures including standing height, body weight, impedance analysis, and neck circumference.	Device: Submental ultrasound; Tongue ultrasound via a submental approach. This non-invasive, pain-free and non-radiating protocol will study both morphological and dynamic characteristics of the tongue. Ultrasonographic assessment will be performed with participants in a resting, supine position and ultrasound gel will be used to optimise submental probe contact.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Tongue stiffness	Tongue stiffness is measured by shear-wave elastography and expressed in kPa.	at baseline and after 30-weeks weight loss program
Tongue thickness	Tongue thickness (expressed in cm) will be measured with ultrasound as the perpendicular distance from the deep fascia of the geniohyoid muscle to the highest lingual dorsum in the midsagittal plane	at baseline and after 30 weeks weight loss program
Echo Intensity	Echo intensity will be measured with ImageJ / Fiji software (ImageJ, US NIH, Bethesda, USA) and refers to the mean value of pixels of an area, based on a grey scale between 0 (black) and 255 (white)	at baseline and after a 30 weeks weight loss program
Acoustic Attenuation	Attenuation will be measured with ultrasound and depicts the quantitative measurement of ultrasound attenuation in tissues. It is expressed as an attenuation coefficient in dB/cm/MHz.	at baseline and after a 30 weeks weight loss program

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Intraclass correlation coefficient, ICC	Intraclass correlation coefficient will be used to assess intra and inter-rater reliability of ultrasound markersUltrasound reliability and repeatability of tongue measurements will be assessed with intraclass correlation coefficients (ICC), along with their 95% confidence intervals. Each ultrasound measurement (tongue size and morphological parameters, echo intensity, stiffness, tissue attenuation imaging, tissue scatter distribution imaging, and fat fraction) in sagittal and coronal planes will be performed twice in fifteen participants by the principal investigator, with a 24-hour interval between examinations.	Baseline
Weight	Weight will be measured with a Tanita scale and expressed in kg	baseline and after a 30 weeks weight loss program
Height	Height will be measured with a stadiometer and expressed in cm	Baseline and after a 30 weeks weight loss program
OSA-18 questionnaire	The OSA-18 is a disease-specific screening tool for early diagnosis of obstructive sleep apnea in children, and is used to evaluate the quality of life before and after treatment. The Obstructive Sleep Apnea - 18 questionnaire is specific to obstructive sleep apnea in children and will be used for correlation analysis. Quality of life is assessed using the Obstructive Sleep Apnea - 18 Quality of Life Survey (OSA-18), a validated questionnaire comprising 18 items. Total scores range from 18 to 126, with higher scores indicating poorer quality of life and greater disease impact, and lower scores reflecting better outcomes.	Baseline and after a 30-weeks weight loss program
Stanford Sleepiness Scale (for adolescents)	The Stanford Sleepiness Scale (SSS) is a single-item, momentary self-report scale assessing current level of alertness and sleepiness on a 7-point ordinal scale, ranging from 1 ("feeling active, vital, alert, or wide awake") to 7 ("no longer fighting sleep, sleep onset soon, having dream-like thoughts"). Originally developed by Hoddes et al. (1973), the scale captures state sleepiness at a given moment rather than habitual sleepiness patterns, making it particularly suitable for repeated within-session assessments. Its adaptation and use in adolescent populations has been documented in pediatric sleep research, where it complements trait-level instruments such as the ESS and PDSS.	Baseline and after a 30-weeks weight loss program
Pediatric Daytime Sleepiness Scale (PDSS)	The Pediatric Daytime Sleepiness Scale (PDSS) is an 8-item self-report questionnaire designed to assess daytime sleepiness in school-aged children and adolescents. Each item is rated on a 5-point Likert scale (0-4), yielding a total score ranging from 0 to 32, with higher scores indicating greater daytime sleepiness. The PDSS was developed and validated by Drake et al. (2003) and has demonstrated adequate internal consistency (Cronbach's α = 0.78) and convergent validity with objective sleep measures. It is specifically designed for pediatric populations and captures sleep-related daytime impairment across academic, behavioral, and social domains. A score ≥ 15 has been proposed as a clinically meaningful threshold for excessive daytime sleepiness in adolescents.	Baseline and after a 30-weeks weight loss program
Epworth Sleepiness Scale (ESS)	The Epworth Sleepiness Scale (ESS) is an 8-item self-report questionnaire assessing the propensity to fall asleep across eight everyday situations, rated on a 4-point Likert scale (0-3), yielding a total score ranging from 0 to 24. Higher scores reflect greater subjective daytime sleepiness. Originally developed and validated by Johns (1991) in adults, the ESS has been subsequently validated for use in adolescent populations and is among the most widely used instruments for screening excessive daytime sleepiness in clinical and research settings. A score > 10 is conventionally considered indicative of excessive daytime sleepiness.	Baseline and after a 30-weeks weight loss program
BMI Z-score	The body mass index Z-score (BMI Z-score, also referred to as BMI standard deviation score) is a age- and sex-standardized measure of body mass index (BMI, kg/m²) that expresses an individual's BMI relative to a reference population of the same age and sex. It is calculated as the deviation of an individual's BMI from the median BMI of the reference population, expressed in units of standard deviation. In pediatric populations, the BMI Z-score is the recommended metric for assessing adiposity and defining weight status categories, as raw BMI values are not directly comparable across age and sex groups due to physiological changes in body composition during growth. In the present study, BMI Z-scores will be calculated according to the World Health Organization (WHO) 2007 reference data for school-aged children and adolescents (5-19 years). Obesity is defined as a BMI Z-score > +2 SD, and overweight as a BMI Z-score between +1 SD and +2 SD above the age- and sex-specific median.	Baseline and after a 30-weeks weight loss program

Collaborators and Investigators

• Sponsor: Vrije Universiteit Brussel

Publications and helpful links

General Publications

• Brockmann, P., & Gozal, D. (2022). Neurocognitive Consequences in Children with Sleep Disordered Breathing: Who Is at Risk? Children, 9(9), 1278. https://doi.org/10.3390/children9091278 Chu, C.-A., Chen, Y.-J., Chang, K.-V., Wu, W.-T., & Özçakar, L. (2021). Reliability of Sonoelastography Measurement of Tongue Muscles and Its Application on Obstructive Sleep Apnea. Frontiers in Physiology, 12, 654667. https://doi.org/10.3389/fphys.2021.654667 da Silva Gusmão Cardoso, T., Pompéia, S., & Miranda, M. C. (2018). Cognitive and behavioral effects of obstructive sleep apnea syndrome in children: A systematic literature review. Sleep Medicine, 46, 46-55. https://doi.org/10.1016/j.sleep.2017.12.020 Gipson, K., Lu, M., & Kinane, T. B. (2019). Sleep-Disordered Breathing in Children. Pediatrics in Review, 40(1), 3-13. https://doi.org/10.1542/pir.2018-0142 Glicksman, A., Hadjiyannakis, S., Barrowman, N., Walker, S., Hoey, L., & Katz, S. L. (2017). Body Fat Distribution Ratios and Obstructive Sleep Apnea Severity in Youth With Obesity. Journal of Clinical Sleep Medicine: JCSM: Official Publication of the American Academy of Sleep Medicine, 13(4), 545-550. https://doi.org/10.5664/jcsm.6538 Halbower, A. C., Degaonkar, M., Barker, P. B., Earley, C. J., Marcus, C. L., Smith, P. L., Prahme, M. C., & Mahone, E. M. (2006). Childhood Obstructive Sleep Apnea Associates with Neuropsychological Deficits and Neuronal Brain Injury. PLoS Medicine, 3(8), e301. https://doi.org/10.1371/journal.pmed.0030301 Yu, J. L., Wiemken, A., Schultz, S. M., Keenan, B. T., Sehgal, C. M., & Schwab, R. J. (2022). A comparison of ultrasound echo intensity to magnetic resonance imaging as a metric for tongue fat evaluation. Sleep, 45(2), zsab295. https://doi.org/10.1093/sleep/zsab295

Study record dates

Study Major Dates

• Study Start (Estimated): September 1, 2026
• Primary Completion (Estimated): September 1, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: May 21, 2026
• First Submitted That Met QC Criteria: May 21, 2026
• First Posted (Actual): May 29, 2026

Study Record Updates

• Last Update Posted (Actual): May 29, 2026
• Last Update Submitted That Met QC Criteria: May 21, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Nutrition Disorders; Overnutrition; Body Weight; Overweight; Pathological Conditions, Signs and Symptoms; Nutritional and Metabolic Diseases; Signs and Symptoms; Obesity; Pediatric Obesity
• Other Study ID Numbers: 26137_EchoTongue

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED
• IPD Plan Description: Individual participant data (IPD) may not be shared publicly, given the sensitive nature of the data collected (health data from minors) and the applicable data protection requirements under the General Data Protection Regulation (GDPR, EU 2016/679). Pseudonymized data will be stored on the secure VUB research data platform (Pixiu) and accessible only to authorized members of the research team. Aggregate and summary data supporting the findings of this study will be made available upon reasonable request to the corresponding author, subject to ethical and institutional approval.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No