Videostroboscopy for the Larynx
Videostroboscopy fulfills several important requirements of a complete voice examination. It provides useful, real-time information concerning the nature of vibration, an image to detect vocal pathology, and a permanent video record of the examination. As important as any of these aspects, stroboscopy substantially improves the sensitivity of subtle laryngeal diagnoses over techniques, such as rigid or flexible transnasal laryngoscopy, with continuous light sources.
A videostrobe unit consists of a stroboscopic unit (light source and microphone), a video camera, an endoscope, and a video recorder. Stroboscopy can be performed by using either rigid or flexible endoscopes; each has its own benefits and drawbacks.
Although flexible endoscopy is ideal for observing unaltered laryngeal behavior from various angles and for viewing the glottis through a narrow supraglottic aperture, it suffers from the low intensity of light carried through the long fiberoptic bundle to the tip of the narrow endoscope. With standard endoscopes, the light bouncing off objects being observed must then travel the length of the endoscope back to a camera or the operator's eye to be detected.
Rigid transoral endoscopy produces a magnified bright image ideal for stroboscopy but requires holding of the patient's tongue throughout the examination, which distorts the natural phonatory posture of the pharynx and larynx. Moreover, the patient must have suitable anatomy and the physical tolerance to allow the clinician to visualize the entire glottis.