Stroboscopy--a pertinent laryngological examination.

When observing the vocal fold movements in their laryngoscopic examination, most laryngologists seem to be trained to consider only the gross respiratory movements of the folds, i.e. abduction and adduction. these movements constitute an essential part of the vitally important valve function of the larynx, preventing aspiration and providing parts of the mechanisms for normal swallowing, coughing, and straining. The second important function of the larynx is to serve as a transducer of aerodynamic to acoustic energy; the voice function. Probably for reasons of tradition, the examination of the voice function is generally left to the speech pathologists, who can make an auditory perceptual evaluation of the voice qualities, possibly supplemented by electro-acoustic analyses. By focussing also on the small vibratory movements of the vocal folds during phonation, using laryngeal stroboscopy, the laryngologist can contribute considerably to the diagnosis of voice disorders. For the laryngeal surgeon stroboscopy should be of particular interest, as it is a useful tool for early detection of (cancerous) invasion and for the evaluation of laryngeal paresis. This paper describes the clinical procedure of laryngeal stroboscopy, based on some introductory remarks on vocal anatomy and function.