Analysis of Changes in Nasal Formant, Spectra and Resonant Volume in Rhinosinus after Endoscopic Sinus Surgery

Kim, Chang Su; Kong, Soo Keun; Lee, Hyun Sun; Cho, Kyu Sup; Wang, Soo Geun; Roh, Hwan Jung

Abstract

BACKGROUND AND OBJECTIVES: There have been some reports about acoustic analysis of nasality changes after endoscopic sinus surgery (ESS), but no studies on the relationship between acoustic and volumetric changes of rhinosinus. The aims of this study were to measure and follow the postoperative course of nasal formant and spectral changes of nasal consonants and vowels, to evaluate the relationship between these acoustic and volumetric changes of rhinosinus, and to estimate the effect of rhinosinus as a nasal tract on nasal resonance after operation. MATERIAL AND METHODS: The changes of formants and spectral pattern were evaluated in 30 patients before ESS, and one, three and 12 months after ESS. Axial CT planes of 10 patients taken before and one month after the surgery were used for measuring the resonant volume of rhinosinus.
RESULTS
The first formant was decreased when ESS was carried out one month after the surgery. However, it almost recovered to the preoperative level within 3 postoperative months. Twelve months after the surgery, the first formant did not show statistically significant differences compared to those of the preoperative state and the postoperative 1 month. The increment of resonant volume in rhinosinus was not correlated with the degree of decrement of the first formant one month after the surgery.
CONCLUSION
Having a proper nasal cavity and the sinuses are important for nasality since hypernasality observed in the postoperative 1 month is thought to be caused by significantly increased resonant volume of the nasal tract. Compensatory control of velopharyngeal port as well as the resonant volume of the nasal tract are important factors to changes in nasality.