Teflon injection in 16 patients with paralytic dysphonia: perceptual and acoustic evaluations

Sixteen patients with paralytic dysphonia were treated with Teflon injection in the paralyzed vocal fold. Trained voice pathologists rated the pre- and postinjection voices on a 5-point scale for each 11 voice characteristics. Among these, aphonia, breathiness, and hypofunction diminished significantly after injection. The perceptual evaluation was correlated with acoustic data from long-time-average spectrum analysis, fundamental frequency distribution analysis, and waveform perturbation analysis. In this acoustic assessment, systematic changes were found in the long-time-average spectra, which agreed well with the perceptual data. In 12 of 16 patients the voice was both perceptually and acoustically improved after Teflon injection.