Normal strobovideolaryngoscopy: variability in healthy singers.

Strobovideolaryngoscopy has proven essential to accurate diagnosis of voice disorders. Clinical interpretation of stroboscopic images usually follows a standard assessment protocol. Features analyzed typically include symmetry of amplitude, symmetry of phase, regularity of periodicity, amplitudes and wave forms of individual vocal folds, presence or absence of adynamic segments, and other features. Speed and smoothness of abduction and adduction are also assessed. In order for stroboscopic data to be used meaningfully in a clinical setting, it is essential for the laryngologist to recognize the range of normal variability of these parameters. This may be particularly important when trying to establish diagnoses for subtle voice disorders in professional voice users. This study investigates strobovideolaryngoscopic findings in a population of normal professional singers without voice complaints. "Abnormal" strobovideolaryngoscopic findings occur in this asymptomatic population of "volunteers." These abnormalities might have been misinterpreted as causing voice complaints if seen for the first time when the singer sought medical care for a voice problem. Physicians must be aware of the range of laryngeal behavior that may be found among normal subjects and must be cautious when interpreting strobovideolaryngoscopic findings. This study also highlights the importance of obtaining "normal" baseline strobovideolaryngoscopic evaluations on professional voice users. The review of strobovideolaryngoscopy performed upon 65 healthy, asymptomatic professional singers revealed an incidence of 58% "abnormal" findings as six clinical entities.