Acoustic Analysis of Autologous Fat Injection versus Thyroplasty in the Same Patient

We objectively measured the acoustic effects of treatment of unilateral vocal fold paralysis by injection of autologous fat and by polytetrafluoroethylene thyroplasty, in the same patient. To our knowledge, this is the first report comparing the two techniques by using the patient's normal voice as the control. The voice of a male patient was recorded before and after onset of unilateral vocal fold paralysis, after treatment with autologous fat, and after polytetrafluoroethylene thyroplasty. Acoustic analysis was performed on a long-term average spectrum of text and on the MDVP (Kay Elemetrics) evaluation of the vowel /a/. Jitter and shimmer were not normalized, but they improved to a greater extent after fat injection. The cepstral peak prominence, spectral skewness, and long-term average spectrum returned to preparalytic values after both treatments, but improved to a greater extent after fat injection. This study showed that both techniques can return the voice to preparalytic values. Spectral measurements best reflected the voice improvement. Further prospective studies in a larger number of patients will be necessary to confirm these results and to determine the long-term objective voice outcome obtained with these techniques.