Laser projection imaging for measurement of pediatric voice

Authors

  • Rita R. Patel PhD CCC-SLP,

    Corresponding author
    1. Department of Rehabilitation Sciences, Division of Communication Sciences and DisordersUniversity of Kentucky, Lexington, Kentucky, U.S.A
    • University of Kentucky, 900 South Limestone, 120 D, Charles T. Wethington Building, Lexington, KY 40536-0200
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  • Kevin D. Donohue PhD,

    1. Department of Electrical and Computer EngineeringUniversity of Kentucky, Lexington, Kentucky, U.S.A
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  • Weston C. Johnson MS,

    1. Department of Electrical and Computer EngineeringUniversity of Kentucky, Lexington, Kentucky, U.S.A
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  • Sanford M. Archer MD

    1. Department of Surgery, Division of Otolaryngology Head and Neck Surgery, University of Kentucky, Lexington, Kentucky, U.S.A
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  • This research was supported by American Speech-Language and Hearing Foundation's New Investigator Research Grant and University of Kentucky, College of Health Sciences, Office of Research Grant, NIH/NIDCD R03DC011360-01. The authors have no other funding, financial relationships, or conflicts of interest to disclose.

Abstract

Objectives/Hypothesis:

The aim of the study was to present the development of a miniature laser projection endoscope and to quantify vocal fold length and vibratory amplitude of the pediatric glottis using high-speed digital imaging coupled with the laser endoscope.

Study Design:

For this prospective study, absolute measurement of entire vocal fold length, membranous length of the vocal fold, and vibratory amplitude during phonation were obtained in one child (9 years old), one adult male (36 years old), and one adult female (20 years old) with the use of high-speed digital imaging, coupled with a custom-developed laser projection endoscope.

Methods:

The laser projection system consists of a module slip-fit sleeve with two 3-mW 650-nm laser diodes in horizontal orientation separated by a distance of 5 mm. Calibration involved projecting the laser onto grid patterns at depths ranging from 6 to 10 cm and tilt angles of 15 to −5 degrees to obtain pixel-to-millimeter conversion templates. Measurements of vocal fold length and vibratory amplitude were extracted based on methods of image processing.

Results:

The system demonstrated a method for estimating vocal fold length and vibratory amplitude with a single laser point with high measurement precision. First measurements of vocal fold length (6.8 mm) and vibratory amplitude (0.25 mm) during phonation in a pediatric participant are reported.

Conclusions:

The proposed laser projection system can be used to obtain absolute length and vibratory measurements of the pediatric glottis. The projection system can be used with stroboscopy or high-speed digital imaging systems with a 70-degree rigid endoscope.

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