Laryngeal Imaging

Rita R. Patel, Ph.D., CCC-SLP
Indiana University
Department of Speech, Language and Hearing Sciences
Bloomington, Indiana,
United States

Jan G. Švec , Ph.D.
Palacky University Olomouc
Faculty of Sciences, Department of Biophysics
Olomouc
Czech Republic


Visualization of the structure and function of the larynx through techniques of laryngeal imaging is key for appropriate evaluation and management of voice disorders. Laryngeal imaging is a broad area which comprises of various modalities including X-rays, Computerized Tomography, Magnetic Resonance Imaging, Ultrasound Imaging, Endoscopy, Stroboscopy, Videokymography, High-speed videoendoscopy, etc. In this Journal of Voice classics series of collection of articles on the topic of ‘Laryngeal Imaging’ we decided to focus only on various endoscopy based techniques used for viewing the vocal folds. Under this topic of ‘Laryngeal Imaging,’ we grouped the articles into two broad categories of (1) Laryngeal Endoscopy and Stroboscopy, and (2) Laryngeal High-Speed Videoendoscopy & Kymography. Each section begins with review article/s that provides a comprehensive historical perspective.

The first issue of the Journal of Voice appeared in 1987 and started to witness tremendous growth and expansion in the field of laryngeal imaging occurring in this era. The list of articles below is not a comprehensive list of all articles published on the topic of laryngeal imaging in the Journal of Voice from 1987 to 2017; however it represents selected list of articles in chronological order that the authors consider are ‘classics’ published in the Journal of Voice in the area of ‘Laryngeal Imaging.’ We decided to use a broader definition of a ‘classic’ rather than a large number of citations as this offers not only the widely cited articles, but also an overview of areas of research and expansion in technology in this area since 1987.*

The beginnings of laryngeal endoscopy and stroboscopy can be traced back to the 19th century when first experiences using these methods were gathered and the methods started to be used clinically. The 20th century saw innovation in terms of instrumentation (flashing light invention for stroboscopes, automated synchronization of stroboscopic flashes with vocal fold vibration, magnifying flexible and rigid scopes, video recordings, etc.). Since 1987 we can follow, through the Journal of Voice articles; further improvements of the instrumentation technology, notably miniaturization, applications of imaging modalities to various voice disorders, use of imaging as a biofeedback in voice therapy, development of evaluation protocols for rating laryngeal findings, etc. From the beginning of the 21st century we can notice efforts in advancing quantification of stroboscopic parameters, further improving intra- & inter-observer reliability of visual evaluation of laryngoscopic and stroboscopic findings, as well as the search for key vibratory features that relate to the overall quality of voice.

High-speed imaging of the larynx and of the vocal folds started in 1930s in United States at the Bell Telephone Labs using a specially developed and bulky cinematographic camera. A crucial step towards clinically usable systems was made in Japan around 1986, shortly before the launch of the Journal of Voice, when the first digital high-speed video camera was developed.

The topic of high-speed videoendoscopy and videokymography first began to appear in Journal of Voice in 1991 when the first article using this modality was published here, bringing information on the vibration of the vocal folds from an infraglottic view. In 1996, the Journal of Voice introduced to the world the alternative, more clinically-oriented high-speed imaging method of videokymography. In 1999 high-speed imaging paper was published investigating voice onset. After the turn of the century the high-speed video technology became more accessible and the number of articles exploring high-speed imaging technology begun to grow. Besides reporting on the improvements in high-speed imaging technology, the main topics of interest of these papers were devoted to accurately quantifying the vast amount of data captured by these modalities using various methods of image processing, providing normative data across age and different types of voice productions, application to various disorders, measuring vibratory onset and offset, quantifying the three-dimensional vibratory motion of the vocal folds, and evaluating the diagnostic potential of the high-speed imaging methods.

Enjoy the reading!

Rita R. Patel and Jan G. Švec

*The articles below have been cited at least 50 times in the Scopus database (as of February 2018).

Laryngeal Endoscopy and Stroboscopy,

 

Laryngeal High-Speed Videoendoscopy & Kymography

 

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