Value of flexible videolaryngoscopy in the study of laryngeal morphology and functions

Standardized laryngeal videostroboscopic rating: differences between untrained and trained male and female subjects, and effects of varying sound intensity, fundamental frequency, and age

To determine the influence of the factors gender, vocal training, sound intensity, pitch, and aging on vocal function, videolaryngostroboscopic images of 214 subjects, subdivided according to gender and status of vocal training, were evaluated by three judges with standardized rating scales, comprising aspects of laryngeal appearance (larynx/pharynx ratio; epiglottal shape; asymmetry arytenoid region; compensatory adjustments; thickness, width, length, and elasticity of vocal folds) and glottal functioning (amplitudes of excursion; duration, percentage, and type of vocal fold closure; phase differences; location of glottal chink). The video registrations were made while the subjects performed a set of phonatory tasks, comprising the utterance of the vowel /i/ at three levels of both fundamental frequency and sound intensity. Analysis of the rating scales showed generally sufficient agreement among judges. With the exception of more frequently observed complete closure and lateral phase differences of vocal fold excursions in trained subjects, no further differences were established between untrained and trained subjects. With an alpha level of p = 0.005, men differed from women with respect to laryngeal appearance (larynx/pharynx ratio, compensatory adjustments, and the presence of omega and deviant-shaped epiglottises), and their vocal folds were rated thicker in the vertical dimension, smaller in the lateral dimension, longer, and more tense, with smaller amplitudes of excursion during vibration. Glottal closure in male subjects was rated more complete, but briefer in duration. Significant effects of the factors pitch, sound intensity, and age on vocal fold appearance and glottal functioning were ascertained. Awareness of the influence of these factors, as well as the factor gender, on the rated scales is essential for an adequate evaluation of laryngostroboscopic images.

Characteristics of normal larynges under flexible fiberscopic and stroboscopic examination: an Australian perspective

The purpose of this study was to investigate the structure and function of larynges of 35 subjects with normal voices. Volunteers aged between 20 and 50 years with no history of voice disorders or laryngeal surgery, no current allergies, no formal voice training, and no hyperactive gag reflex were required to perform various vocal manoeuvres that were carried out under continuous and stroboscopic light. An assessment form was devised to record the condition and function of the larynx. The videotapes of the procedure were rated by experienced judges. The Australian Fiberscopic Profile was devised to record the relevant parameters under continuous light. Videostroboscopic ratings were carried out using the Bless protocol rating. High interjudge agreement was found across the two rating profiles.