Research Proposal on investigating Laryngeal Ultrasonography as an Assessment Tool for Children with Voice Disorders

Visualizing voice disorder: real-time ultrasonographic evaluation of vocal functions

Research question: 

What is the difference in quantitative measurement of vocal fold structures and functions in children with and without voice disorders?

Background information:

Pediatric voice disorder is a common condition among school-aged children with a high prevalence of 11.6% (Carding et al., 2006). Voice problems may lead to impaired communication, adversely impacting the child’s quality of life in the aspects of social integration and self-esteem. Additionally, listeners tend to associate abnormal voice qualities with negative stereotypes and false estimates of personality traits (Ma & Yu, 2013). Therefore, early identification and intervention of voice disorder in children is of high importance.


Larynx examination is necessary for the diagnosis of voice disorder. Flexible nasolaryngoscopy is the current gold standard for evaluating vocal fold movement; however, operation of flexible nasolaryngoscopy is challenging on young children due to difficulty with cooperation, crying, extensive movement, secretions and obstructed supraglottic structures (Ongkasuwan et al., 2016). Given the non-invasive nature, laryngeal ultrasonography has been under investigation as an alternative of assessing vocal mobility in the pediatric population. Application of laryngeal ultrasonography is possible due to children’s absence of thyroid cartilage, thus allowing visualization of vocal folds (Ongkasuwan et al., 2016).



The use of laryngeal ultrasonography has been introduced since the 1970s, primarily applied in investigating fetal human upper respiratory anatomy; little research has been conducted on assessing vocal folds lesions (Spadola Bisetti et al., 2009). In recent literature, laryngeal ultrasonography has been adopted to identify vocal fold movement impairment (VFMI) with 90%-100% diagnostic accuracy, also found to be well-tolerated by young patients and highly accepted by their caregivers (Ongkasuwan et al., 2016). However, no research has been conducted on laryngeal ultrasonography in Hong Kong, resulting in a limited database of laryngeal ultrasound images for diagnostic purposes.



The prevalence of pediatric voice disorders and adverse impacts on one’s quality of life have been overlooked in Hong Kong, given inadequate research and a limited database on the technique laryngeal ultrasonography. The long waiting time for public speech therapy services (i.e., minimally one year) and unaffordability of private clinics result in delayed diagnosis and treatment for patients from low- or mid-income families. Noting that voice problems do not resolve spontaneously, the absence of early intervention may give rise to an unfavorable prognosis.


This research hopes to develop a database of laryngeal ultrasonography of children with and without voice disorders in Hong Kong, establishing a solid foundation to further investigate its accuracy and possibility as a formal assessment for laryngeal diseases in the future. Extending to the global perspective, database derived from this research can be applied cross-culturally to assess the application of laryngeal ultrasonography internationally, given that voice problems are a global issue regardless of language differences. The long-term goal of this research is to incorporate artificial intelligence into voice disorder diagnosis. Making use of deep learning and big data, computers will be set to automatically recognize patterns in laryngeal ultrasound images, thus make further predictions. Additionally, as voice problems frequently occur in school-aged children, it is aspired that laryngeal ultrasonography can be widely used by school-based speech therapists for screening purposes in the future once the technique becomes more well-developed, encouraging early intervention.



Laryngeal ultrasonography will be performed on participants in the supine position with the anterior neck well-extended; the probe will be angled superiorly from the hyoid level to the cricoid cartilage (Wang et al., 2011). For qualitative analysis, the symmetry of vocal fold movement will be recorded, as well as the mobility of right and left vocal folds individually, categorizing into no, partial, and full mobility (Ongkasuwan et al., 2016). For quantitative analysis of vocal fold mobility, the maximum glottic angle (MGA) and vocal fold-arytenoid angle (VAA) will be measured after a maximum inhalation task evaluated at a calm state (e.g., breathing, sleeping) (Wang et al., 2011). Another condition to be evaluated is a vocalizing state (e.g., crying, pronouncing /i/). For the positioning of participants, parents will stabilize infants’ heads or hold older children in their laps.



Laryngeal ultrasonography is not a substitute for a complete airway examination with limited ability to examine vocal fold margins and laryngeal closure patterns (Ongkasuwan et al., 2016). Additionally, the technique cannot be applied on older adults due to the calcification of thyroid cartilage, which impairs visualization of laryngeal structures. Some challenging conditions include limited access to the anterior neck, such as unable to extend the neck or presence of tracheostomy tubes that cannot be removed, making laryngeal ultrasonography infeasible. 


April 2022 - May 2022 

Literature review

Recruitment of participants

Obtaining ethical approval (As this research involves human participants, it is required to obtain ethical approval prior to any data collection from the Human Research Ethics Committee (HREC) for ethical clearance.)

June 2022 - July 2022

6-week data collection period

In collaboration with Dr. Wei-Ning Lee at the Lee Ultrasound Imaging Laboratory, HKU, participants will be recruited from Tseung Kwan O Hospital.

Consent will be obtained from parents prior to any data collection.

August 2022

Qualitative and quantitative data analysis

Reporting of research findings


Hong Kong



Carding, P. N., Roulstone, S., Northstone, K., & ALSPAC Study Team. (2006). The prevalence of childhood dysphonia: A cross-sectional study. Journal of Voice, 20(4), 623–630. 

Ma, E. P.-M., & Yu, C. H.-Y. (2013). Listeners' attitudes toward children with voice problems. Journal of Speech, Language, and Hearing Research, 56(5), 1409–1415. 

Ongkasuwan, J., Ocampo, E., & Tran, B. (2016). Laryngeal ultrasound and vocal fold movement in the Pediatric Cardiovascular Intensive Care Unit. The Laryngoscope, 127(1), 167–172. 

Spadola Bisetti, M., Segala, F., Zappia, F., Albera, R., Ottaviani, F., & Schindler, A. (2009). Non-invasive assessment of benign vocal folds lesions in children by means of ultrasonography. International Journal of Pediatric Otorhinolaryngology, 73(8), 1160–1162. 

Wang, L. M., Zhu, Q., Ma, T., Li, J. P., Hu, R., Rong, X. Y., Xu, W., & Wang, Z. C. (2011). Value of ultrasonography in diagnosis of pediatric vocal fold paralysis. International Journal of Pediatric Otorhinolaryngology, 75(9), 1186–1190.