Secondary Logo

Share this article on:

Current approaches to instrumental assessment of swallowing in children

Dharmarathna, Isurua; Miles, Annaa; Allen, Jacqui E.b,c

Current Opinion in Otolaryngology & Head and Neck Surgery: December 2018 - Volume 26 - Issue 6 - p 349–355
doi: 10.1097/MOO.0000000000000492
LARYNGOLOGY AND BRONCHOESOPHAGOLOGY: Edited by Jacqui E. Allen

Purpose of the review This article reviews recent developments in the instrumental assessment of swallowing in children with a specific focus on research published between January 2017 and June 2018.

Recent findings Instrumental swallowing assessments reported in the time period included: videofluoroscopic study of swallowing, digital cervical auscultation, dynamic ultrasound, high-resolution impedance manometry, nasal airflow thermistry and respiratory inductance plethysmography. Several studies were found exploring tools to objectively quantify videofluoroscopic study of swallowing data; swallowing from the mouth through to stomach was addressed including approaches to analysing mastication as well as evaluating oesophageal motility disorders.

Summary Even though a vast range of instrumentation were studied, lack of clarity on clinical feasibility and objective measures that facilitate medical decision-making in practice mean further research is required to provide guidance on implementation. Promising novel approaches to aid the quantification of swallowing physiology from the mouth, pharynx and through to the oesophagus are emerging.

aSpeech Science

bDepartment of Surgery, The University of Auckland

cWaitemata District Health Board, Auckland, New Zealand

Correspondence to Isuru Dharmarathna, BSc, Speech Science, School of Psychology, Tamaki Campus, The University of Auckland, Private Bag 92019, Auckland, New Zealand. Tel: +64 9 923 8177; fax: +64 9 373 7902; e-mail: pdha800@aucklanduni.ac.nz

Back to Top | Article Outline

INTRODUCTION

With the development of medical and surgical advances in treating premature and fragile infants, prevalence of paediatric swallow disorders has increased [1]. Paediatric dysphagia is associated with acute and long-term health complications (respiratory, nutritional and psychosocial), which may persist into adulthood. Consequences of swallowing impairments can be reduced by early detection and effective intervention [2]. Clinical feeding assessment (CFA) is the initial tool used to identify risk of disordered swallowing in children [1]. Although ideal for many critical observational parameters, CFA has poor validity and reliability in documenting pharyngo-oesophageal physiology and identifying aspiration when compared to instrumental assessments [3,4]. Duncan et al. [5▪] postulate that ‘incompetent CFA’ delays diagnosis and appropriate management in children, pointing to its failure to correctly identify 61% of children who were positive for aspiration on videofluoroscopic study of swallowing (VFSS). These concerns have led researchers to focus on developing more reliable and objective instrumental measures of swallowing in children in the recent past. However, clinical applicability of these innovative methods, such as quantifying physiological deviations from typical swallowing development, is still in progress [6,7].

The instrumental assessments investigating oral, pharyngeal and oesophageal phases of swallowing can be classified broadly as: visual imaging, pressure-flow or impedance measures and respiratory/acoustic measures (Fig. 1).

FIGURE 1

FIGURE 1

Box 1

Box 1

Back to Top | Article Outline

VISUAL IMAGING

Videofluoroscopic study of swallowing

VFSS is considered the gold standard clinical assessment of swallowing in both children and adults, with the advantage that it directly visualizes all phases of swallowing [8]. Despite its availability and popularity, interpretation of VFSS findings, in many cases, remains largely subjective [9]. In the last 2 years, a number of studies have challenged subjective interpretation of VFSS findings.

The widely used Penetration-Aspiration Scale [10] is applied to videofluoroscopic imaging studies to grade airway violation during swallowing. It was critically reviewed by Steele and Grace-Martin [11] in terms of its clinical and research use. The Penetration-Aspiration Scale is used across the lifespan in VFSS [12] and has also been adapted for functional endoscopic evaluation of swallowing (FEES) [12–15]. The authors question using the scale as ‘ordinal’ in research data analysis and make suggestions for alternative ways to code or interpret the scale.

By establishing quantitative timing and displacement VFSS measures for healthy adults, Leonard et al. [16] and Kendall et al. [17] have shown its great clinical potential for improving accuracy of physiological diagnostics to aid decision-making in swallowing management. In the United States, Lee et al. [9] reported subjective measures of hyoid elevation, pharyngeal constriction ratio and pharyngo-oesophageal segment opening to be highly inconsistent among raters with accuracy ranging from 45 to 72%, compared with objective measures of adult VFSS. Further, they emphasize the importance of objective analysis of VFSS measures to standardize its interpretation, by revealing moderate overall inter-rater reliability of subjective VFSS measures. Meanwhile, in New Zealand, The University of Auckland Swallowing Laboratory explored competency development in obtaining objective measures of adult VFSS [18]. They found that speech and language therapists could learn and rate objective VFSS measures within a feasible time frame, irrespective of their level of experience, which is promising for its potential to offer reproducible objective measures for specific standardized care [18]. These findings are relevant and likely to be transferable to paediatric populations.

Objective quantifiable VFSS measures of children have been widely explored in the research arena in the recent past. In 2015, Gosa et al. [19] explored 15 objective temporal and physiologic measures of VFSS in children and found them all to be reliably measured. Henderson et al. [20] explored the feasibility of obtaining objective measures of timing and displacement in a paediatric VFSS clinic. They found that feasible and reproducible measures could be obtained by adopting a protocol, recording at an increased frame rate for short bursts, which overall did not increase radiation dose or exposure time. Sales et al. [21▪▪]describe a quantitative and qualitative temporal analysis of oropharyngeal swallowing in children with Down syndrome. Six qualitative binary parameters with two quantitative parameters were described in oral and pharyngeal phases of swallowing. Qualitative measures (oral incoordination, labial sphincter sealing incompetence, oral residue, posterior oral spillage, laryngo-tracheal penetration and laryngo-tracheal aspiration) were marked ‘binary’, as either present or absent, whereas pharyngeal transit time and total oral transit time were analyzed using a specific software [21▪▪]. This study is identified as the first to analyze objective temporal measures of swallowing in children with Down syndrome, recommending further studies with larger samples for quantitative analysis of swallowing in this clinical population.

Hyoid displacement plays an important role in airway protection during swallowing. Reduced hyoid displacement is associated with increased risk of residue and aspiration in adults [22]. However, it has not been studied extensively in paediatrics. In a multicentre collaboration, Riley et al. [23▪▪] explored feasibility of measuring positioning and displacement of hyoid bone during swallowing in paediatric VFSS. They found visibility of hyoid bone increased with age, and was rarely visible in infants less than 9 months. This preliminary study is the first to explore objective hyoid measurements in children and leads to opportunities for further understanding of the role of the hyoid in the developing child.

Further work is required assessing training requirements and reliability of quantitative VFSS measures in children as well as building an understanding of swallowing physiological patterns across ages, severity profiles and cause (Fig. 2).

FIGURE 2

FIGURE 2

Back to Top | Article Outline

Modified barium swallow impairment profile

In 2018, Lefton-Greif et al. [24▪▪] reported the Modified Barium Swallow Impairment Profile (MBSImP) for bottle-fed children. The MBSImP [25] is a standardized tool for systematic interpretation of adult VFSS images. The paediatric version of the MBSImP includes components of bolus flow and physiologic movements of oropharyngeal structures during swallowing, which were identified by clinical experts, as essential for functional, efficient and well-tolerated swallowing in bottle-fed infants. MBSImP was used as the conceptual assessment tool to identify and quantify swallowing impairment. The authors tested inter-rater reliability, achieving 80% reliability by all the raters after completing three training–testing sessions. MBSImP for bottle-fed children offers clinicians working in paediatric dysphagia, a reliable systematic observation and criterion-based scoring of the swallowing mechanism.

Back to Top | Article Outline

Ultrasound

Ultrasound, with the advantage of not exposing infants to ionizing radiation, has future potential as a noninvasive method of assessing swallowing physiology. In 2017, Remijn et al. [26] studied the oral stage of swallowing in children, aiming to describe the process of mastication. They explored the feasibility of the Mastication Observation and Evaluation tool, using dynamic ultrasound and 3D kinematic measures of masticatory skills in children with cerebral palsy, compared with typically developing children. The researchers first introduced this tool in 2014 [27], and then explored the measurement of mandibular movements in adults in 2016. In this most recent study, they used video-recorded ultrasound to measure horizontal and vertical movements of tongue and 3D kinematics to measure horizontal, vertical and anterior mandibular movements. Both 3D kinematics and ultrasound measures were capable of successfully differentiating disordered from healthy mastication in terms of frequency and timing of movements and duration of chewing cycles. The authors conclude that these objective ultrasound measures of tongue movements and timing measures could complement the Mastication Observation and Evaluation findings clinically. However, the need for specialized equipment and intensive training to administer and interpret ultrasound findings may restrict its practical clinical use among speech and language therapists [28▪].

Back to Top | Article Outline

PRESSURE FLOW AND IMPEDANCE

Manometry is a valid measure of pharyngeal and oesophageal pressures across time during swallowing. In adults, manometry measures are beneficial in planning surgical interventions, such as candidacy for cricopharyngeal myotomy [29]. High-resolution pharyngo-oesophageal manometry with impedance has gained popularity in the last decade, providing vital information on bolus pressure and flow in pharyngeal and oesophageal phases of swallowing.

Back to Top | Article Outline

Oesophageal manometry

This year, Singendonk et al. [30▪]trialled a novel approach by combining pressure and impedance measures to evaluate oesophageal motility in children with achalasia. In this study, high-resolution oesophageal manometry was administered to children with achalasia and children without an oesophageal motility disorder using a standardized protocol. Measures included three oesophageal junction parameters: integrated relaxation pressure (IRP), bolus flow time (BFT) and bolus presence time (BPT). In achalasia, significantly lower BPT and BFT values were reported, compared with children without motility disorders. No significant differences were observed in BPT and BFT of treated and untreated groups of achalasia, suggesting that children may still exhibit persisting symptoms postdilatation therapy. In this study, selected oesophageal junction parameters successfully indicate oesophageal dysmotility in children with achalasia and it could be developed further for diagnosing a range of motility disorders as well as guiding decision-making and measuring efficacy of treatments (Fig. 3).

FIGURE 3

FIGURE 3

Back to Top | Article Outline

Pharyngeal manometry

Pharyngeal manometry is a ‘hot topic’ across the lifespan. In 2018, Hasenstab et al. [31]studied how maturation affects respiratory, pharyngeal and oesophageal aerodigestive rhythms during multiple pharyngeal swallow sequences. Preterm infants were studied longitudinally (for 4 weeks) to determine the effect on maturation and pharyngeal stimulus volume on multiple swallow response rhythms and respiratory characteristics. Pharyngo-oesophageal manometry results were analyzed to identify and describe pharyngeal swallow responses (PSR), by calculating frequency of multiple PSR for each participant. Further, multiple PSR were analyzed to calculate the number of pharyngeal peaks, pharyngeal frequency and stability. They report decreases in the number of pharyngeal peaks and pharyngeal peak duration, as infants advance in maturation. These findings expand our understanding of how preterm infants achieve stability in swallowing over the time, while maintaining airway protection. Pharyngeal manometry is likely to be seen more often in paediatric swallowing assessment in coming years.

Back to Top | Article Outline

RESPIRATORY MEASURES

It is well known that airway protection during swallowing is essential for survival. Neurological maturation and development is complex and therefore coordination of breathing, sucking and swallowing in preterm infants has been extensively studied [32]. Hasenstab et al. [31]used respiratory inductance plethysmography and nasal airflow thermistor readings alongside their manometry measures. Respiratory measures included: prevalence of deglutition apnoea, duration of deglutition apnoea, respiratory response latency, respiratory response duration and total respiratory rhythm change duration. Duration of deglutition apnoea significantly decreased with maturation. Moreover, their findings reflect similarity in findings of the literature, by suggesting that maturation modifies respiratory adaptive behaviours [33,34]. Authors acknowledge this study to be the first to investigate respiratory and pharyngeal characteristics of PSR patterns in neonates. This may add to our understanding of swallowing–respiration coordination in premature infants. The feasibility of using airflow measures in the clinic to guide management decisions is yet to be established.

Back to Top | Article Outline

ACOUSTIC MEASURES

Acceptance of cervical auscultation as an instrumental assessment is controversial. Some researchers question the correlation between cervical auscultation sounds and physiology of swallowing [28▪]. Yet, objective acoustic measures for children have been widely studied and standardized over the years [35–37]. In 2013, Frakking et al. [36] proved its potential as a diagnostic test to identify risk of oropharyngeal aspiration in children. However, they acknowledge that clinical significance of acoustic swallowing measures could be limited, if not related to perceptual parameters in interpreting swallowing sounds. Taking their research further, Frakking et al. [38]aimed to develop normative data of acoustic and perceptual profiles of swallow sounds for 4–36 months old children using digital cervical auscultation. They studied healthy children aged 4–36 months, who are within the transitional feeding period, as significant changes to anatomical maturity of oropharynx take place during this period [39]. Swallowing-related laryngeal movements were video recorded and an acoustic software was used to analyze the correlating auditory feedback of the swallow sound. Three acoustic parameters were analyzed for food and liquid consistencies: swallow duration, peak frequency and peak intensity/amplitude. They found the mean duration of swallows was less than 1 s for all food consistencies in children, whereas thin fluids marked the highest peak frequency and peak amplitude mean. A significant positive correlation was reported between peak amplitudes and age; the swallow sounds become louder as children get older. This study adds the largest collection of normative data to the previously developed normative data for different paediatric age groups [35,40]. However, the study fails to provide reliability ratings or to compare the acoustic measures with physiological measures of swallowing to see which swallow sound represents which physiological event during swallowing in children. The authors suggest considering mean swallow duration (<1 s) as a marker to identify healthy swallowing in children. This approach may drive future research directions, as it is noninvasive and less costly compared to existing instrumentations. Accessibility and ease of administration are advantages for clinical use.

Back to Top | Article Outline

FUTURE DIRECTIONS FOR INSTRUMENTAL ASSESSMENTS OF SWALLOWING

Standardizing quantitative and objective measures remains a priority in the field of paediatric instrumental swallowing assessment. Research should focus on clinically feasible, objective, quantitative reporting of physiological components of swallowing to facilitate medical and surgical decision-making for children with complaints of dysphagia. Considering the importance of VFSS as the gold standard visual-imaging assessment method and its technological development in the recent past, it is unacceptable to expose children to radiation only to confirm presence of aspiration. Rather, it should guide clinicians’ understanding of the underlying anatomical and physiological manifestations causing swallow dysfunction and aspiration. Establishing standard objective VFSS measures across developmental ages and different causes of swallowing should be a priority. As a nonradiological, yet invasive procedure, manometry with impedance has great potential to describe pharyngeal and oesophageal phases of swallowing, in terms of motility and pressure flow. FEES, another nonionizing invasive procedure, provides important information on pharyngo-laryngeal structure and function of airway protection during swallowing [28▪]. Even though no published scientific articles were found during the reviewed time period, it may prove worthwhile combining FEES with respiratory measures to describe swallowing–breathing coordination in young children. Development of specific and holistic management approaches for children, including novel noninvasive instrumental swallowing assessment, is needed.

Back to Top | Article Outline

CONCLUSION

The breadth of research into instrumental assessment of children is vast with a wide range of instrumental tools under investigation. Yet, there remains a lack of clarity on clinical feasibility and objective measures which facilitate medical decision-making in practice. Novel approaches to aid the quantification of swallowing physiology from the mouth, pharynx through to the oesophagus are emerging. Quantitative measures of VFSS, high-resolution manometry with impedance and ultrasound hold merit in the clinical setting.

Back to Top | Article Outline

Acknowledgements

We would like to thank Lisa McCall, Registered Nurse in the Gastroenterology Unit at Women's & Children's Hospital, Adelaide for Fig. 3.

Back to Top | Article Outline

Financial support and sponsorship

None.

Back to Top | Article Outline

Conflicts of interest

There are no conflicts of interest.

Back to Top | Article Outline

REFERENCES AND RECOMMENDED READING

Papers of particular interest, published within the annual period of review, have been highlighted as:

  • ▪ of special interest
  • ▪▪ of outstanding interest
Back to Top | Article Outline

REFERENCES

1. Arvedson JC. Assessment of pediatric dysphagia and feeding disorders: clinical and instrumental approaches. Dev Disabil Res Rev 2008; 14:118–127.
2. Khoshoo V, Ross G, Kelly B, et al. Benefits of thickened feeds in previously healthy infants with respiratory syncytial viral bronchiolitis. Pediatr Pulmonol 2001; 31:301–302.
3. Splaingard ML, Hutchins B, Sulton LD, Chaudhuri G. Aspiration in rehabilitation patients: videofluoroscopy vs bedside clinical assessment. Arch Phys Med Rehabil 1988; 69:637–640.
4. McCullogh GH, Wertz RT, Rosenbek JC. Sensitivity and specificity of clinical/bedside examination signs for detecting aspiration in adults subsequent to stroke. J Commun Disord 2001; 34:55–72.
5▪. Duncan DR, Larson K, Hester L, et al. The clinical feeding evaluation has poor reliability in the assessment of pediatric swallow function and causes delays in the diagnosis of aspiration. Gastroenterology 2017; 152:S708–S709.

The article reports findings concerning the extensive use of clinical feeding assessments to diagnose dysphagia in children. Further, it discusses how accuracy varies among clinicians in interpreting CFA findings.

6. Arvedson J, Rogers B, Buck G, et al. Silent aspiration prominent in children with dysphagia. Int J Pediatr Otorhinolaryngol 1994; 28:173–181.
7. Kim J, Oh B-M, Kim JY, et al. Validation of the videofluoroscopic dysphagia scale in various etiologies. Dysphagia 2014; 29:438–443.
8. Logemann JA. Behavioral management for oropharyngeal dysphagia. Folia Phoniatr Logop 1999; 51:199–212.
9. Lee JW, Randall DR, Evangelista LM, et al. Subjective assessment of videofluoroscopic swallow studies. Otolaryngol Head Neck Surg 2017; 156:901–905.
10. Rosenbek JC, Robbins JA, Roecker EB, et al. A penetration aspiration scale. Dysphagia 1996; 11:93–98.
11. Steele CM, Grace-Martin K. Reflections on clinical and statistical use of the penetration-aspiration scale. Dysphagia 2017; 32:601–616.
12. Kelly AM, Drinnan MJ, Leslie P. Assessing penetration and aspiration: how do videofluoroscopy and fiberoptic endoscopic evaluation of swallowing compare? Laryngoscope 2007; 117:1723–1727.
13. Colodny N. Interjudge and intrajudge reliabilities in fiberoptic endoscopic evaluation of swallowing (FEES) using the penetration-aspiration scale: a replication study. Dysphagia 2002; 17:308–315.
14. Rao N, Brady SL, Chaudhuri G, et al. Gold standard: analysis of the videofluoroscopic and fiberoptic endoscopic swallow examinations. J Appl Res Clin Exp Ther 2003; 3:89–96.
15. Butler SG, Stuart A, Case LD, et al. Effects of liquid type, delivery method, and bolus volume on penetration-aspiration scores in healthy older adults during flexible endoscopic evaluation of swallowing. Ann Otol Rhinol Laryngol 2011; 120:288–295.
16. Leonard RJ, Kendall KA, McKenzie S, et al. Structural displacements in normal swallowing: a videofluoroscopic study. Dysphagia 2000; 15:146–152.
17. Kendall KA, McKenzie S, Leonard RJ, et al. Timing of events in normal swallowing: a videofluoroscopic study. Dysphagia 2000; 15:74–83.
18. Nordin NA, Miles A, Allen J. Measuring competency development in objective evaluation of videofluoroscopic swallowing studies. Dysphagia 2017; 32:427–436.
19. Gosa MM, Suiter DM, Kahane JC. Reliability for identification of a select set of temporal and physiologic features of infant swallows. Am J Otolaryngol 2015; 30:365–372.
20. Henderson M, Miles A, Holgate V, et al. Application and verification of quantitative objective videofluoroscopic swallowing measures in a pediatric population with dysphagia. J Pediatr 2016; 178:200–205.
21▪▪. Sales AV, Giacheti CM, Cola PC, Silva RG. Qualitative and quantitative analysis of oropharyngeal swallowing in Down syndrome. CoDAS 2017; 29:e20170005.

The article reports both quantitative and qualitative measures of swallowing in children with Down syndrome. With a small sample size, the study focuses on measuring two timing measures of oropharyngeal swallowing quantitatively, whereas qualitatively analysing presence and frequency of six qualitative oropharyngeal swallowing parameters.

22. Choi KH, Ryu JS, Kim MY, et al. Kinematic analysis of dysphagia: significant parameters of aspiration related to bolus viscosity. Dysphagia 2011; 26:392–398.
23▪▪. Riley A, Miles A, Steele CM. An exploratory study of hyoid visibility, position and swallowing-related displacement in a pediatric population. Dysphagia 2018; In review.

This exploratory study investigates feasibility of visualising hyoid bone displacement during swallowing in a group of children ranging from newborns to 21 years old. This reports how hyoid bone displacement was clearly and reliably visualized in VFSS of children more than 9 months old.

24▪▪. Lefton-Greif MA, McGrattan KE, Carson KA, et al. First steps towards development of an instrument for the reproducible quantification of oropharyngeal swallow physiology in bottle-fed children. Dysphagia 2018; 33:76–82.

The study reports the process of developing a standard protocol to obtain criterion-based interpretation of oropharyngeal swallowing physiology in bottle-fed children using VFSS, with inter-rater reliability testing.

25. Martin-Harris B, Brodsky MB, Michel Y, et al. MBS measurement tool for swallow impairment – MBSImp: establishing a standard. Dysphagia 2008; 23:392–405.
26. Remijn L, Groen BE, Speyer R, et al. Can mastication in children with cerebral palsy be analyzed by clinical observation, dynamic ultrasound and 3D kinematics? J Electromyogr Kinesiol 2017; 32:22–29.
27. Remijn L, Speyer R, Groen BE, et al. Validity and reliability of the Mastication Observation and Evaluation (MOE) instrument. Res Dev Disabil 2014; 35:1551–1561.
28▪. Arvedson JC, Lefton-Greif MA. Instrumental assessment of pediatric dysphagia. Semin Speech Lang 2017; 38:135–146.

This review discusses commonly used instrumental assessments such as VFSS, FEES in paediatric swallowing management and provides updates for clinicians.

29. Leonard R, Kendall K. Dysphagia assessment and treatment planning: a team approach. 3rd ed.San Diego: Plural Publishing; 2013.
30▪. Singendonk MM, Omari TI, Rommel N, et al. Novel pressure-impedance parameters for evaluating esophageal function in pediatric achalasia. J Pediatr Gastroenterol Nutr 2018; 66:37–42.

This study investigates oesophageal motility dysfunction in children with achalasia, using oesophageal manometry. It reports significantly lower BPT and BFT in children with achalasia, indicating the potential of manometry as an objective diagnostic tool in identifying motility disorders in children

31. Hasenstab KA, Sitaram S, Lang IM, et al. Maturation modulates pharyngeal-stimulus provoked pharyngeal and respiratory rhythms in human infants. Dysphagia 2018; 33:63–75.
32. Goldfield EC, Smith V. Preterm infant swallowing and respiration coordination during oral feeding: relationship to dysphagia and aspiration. Curr Pediatr Rev 2010; 6:143–150.
33. Jadcherla SR, Gupta A, Stoner E, et al. Pharyngeal swallowing: defining pharyngeal and upper esophageal sphincter relationships in human neonates. J Pediatr 2007; 151:597–603.
34. Jadcherla SR, Shubert TR, Gulati IK, et al. Upper and lower esophageal sphincter kinetics are modified during maturation: effect of pharyngeal stimulus in premature infants. Pediatr Res 2015; 77:99–106.
35. Vice FL, Heinz JM, Giuriati G, et al. Cervical auscultation of suckle feeding in newborn infants. Dev Med Child Neurol 1990; 32:760–768.
36. Frakking TT, Chang AB, O’Grady KAF, et al. Cervical auscultation in the diagnosis of oropharyngeal aspiration in children: a study protocol for a randomised controlled trial. Trials 2013; 14:377.
37. Frakking TT, Chang AB, O’Grady KF, et al. Aspirating and nonaspirating sounds in children: a pilot study. Ann Otol Rhinol Laryngol 2016; 125:1001–1009.
38. Frakking TT, Chang AB, O’Grady KAF, et al. Acoustic and perceptual profiles of swallowing sounds in children: normative data for 4-36 months from a cross-sectional study cohort. Dysphagia 2017; 32:261–270.
39. Hall KD. Paediatric dysphagia resource guide. Boston: Delmar Cengage Learning; 2001.
40. Almeida ST, Ferlin EL, Parente MA, Goldani HA. Assessment of swallowing sounds by digital cervical auscultation in children. Ann Otol Rhinol Laryngol 2008; 117:253–258.
Keywords:

deglutition disorders; dysphagia; instrumental assessment; manometry; paediatric feeding; videofluoroscopic study of swallowing

Copyright © 2018 Wolters Kluwer Health, Inc. All rights reserved.