Changes in voice characteristics after uvulopalatopharyngoplasty.

Previous reports have warned that tonsillectomy or uvulopalatopharyngoplasty (UPPP) may alter patients' speech by increasing the amount of nasal resonance as well as by changing voice timbre due to enlargement of the vocal tract. However, very few objective investigations, excluding nasality problems, have been carried out. We studied eight patients who underwent surgery for UPPP and recorded pre- and postoperative speech. The speech samples were then rated by seven experienced listeners, and acoustic spectra of two long vowels,/a/ and /e/, were analyzed using a computer program (MacSpeech Lab II). The listeners were unable to make a distinction between pre- and postoperative voice samples in the recordings studied. Acoustic analysis showed that the fundamental frequency as well as the first and second formants remained essentially unchanged. Present findings show that UPPP should not have a significant effect on voice characteristics as long as excessive nasality is not produced.