We examined the vocal folds of seven patients (six severe and one moderate; six females and one male; aged 55–74 years; mean 64.7 years) with Reinke's edema using HSDI and videostroboscopy. The following characteristics were analyzed: glottic closure, mucosal-wave propagation, left–right asymmetry, phase shift, frequency difference, periodicity, and contact of the true vocal fold with the false vocal fold.
HSDI revealed complete glottic closure, anterior–posterior phase shift, and obvious contact of at least one side of the edematous true vocal fold with the ipsilateral false vocal fold in all patients. Mucosal-wave propagation increased in six patients and decreased in one. Left–right asymmetry was observed in six patients. Left–right phase shifts and left–right frequency differences were observed in four and two patients, respectively. The vibration was periodic in four patients, quasi-periodic in three, and aperiodic in none. Anterior–posterior frequency differences were not observed for any patient. The vocal-fold vibration always synchronized with strobolights in two patients, while the vibration occasionally and never synchronized in two and three patients, respectively. In one patient whose vibration occasionally synchronized, videostroboscopy could not reveal the slight left–right frequency difference of the vibration.
It was often difficult to observe vocal-fold vibration correctly in patients with severe Reinke's edema using videostroboscopy. However, HSDI was useful for examining these patients. Our results suggest that HSDI can be very useful for examining the vocal folds of patients with severe Reinke's edema.