An Acoustic and Radiologic Study on Voice Change after Tonsillectomy and Adenotonsillectomy

Lee, Jong Hwan; Koo, Gyo Jun; Koo, Han Eol; Kim, Yu Chan; Koo, Soo Kweon; Lee, Sang Hwa; Wang, Soo Guen; Kim, Hak Jin; Yang, Byung Gon

Abstract

BACKGROUND AND OBJECTIVES: Some patients who have undergone tonsillectomy complain of voice change, but few studies for the mechanism of voice change were found. To solve this problem, study of voice change after tonsillectomy and adenotonsillectomy was done.
MATERIALS AND METHODS
We analyzed voice change of 22 patients who underwent tonsillectomy and 15 patients who underwent adenotonsillectomy at CSL (computerized speech laboratory), St. Benedict Hospital. With the measured cross sectional area of vocal tract and its length from the glottis on MR images, we presented the change of cross sectional area schematically after tonsillectomy.
RESULTS
Acoustically, the frequencies of the second formant of /e/ and /i/ increased and that of the first formant of /u/ decreased significantly after tonsillectomy and the frequency of the second formant of /o/ and those of the second and third formants of /i/ and /u/ increased significantly after adenotonsillectomy. It was also showed acoustically that the formant bandwidths of /a/ and /hana/ after tonsillectomy and those of /e/ and /hana/ after adenotonsillectomy increased due to nasalization. Anatomically, it was showed that the cross sectional area of oropharyngeal cavity increased and coupling effect of vocal tract happened after tonsillectomy.
CONCLUSION
This study showed that acoustic characteristics and vocal tract shapes of the patients did change following tonsillectomy and adenotonsillectomy. It is imperative that we explain to patients about the postoperative voice change. Research should also be done to find ways to induce better voice changes following the operations.