Acoustic characteristics of speech following uvulopalatopharyngoplasty.

Selective uvulopalatopharyngoplasty has resulted in the improved management of sleep apnea; however, the effect of the surgery on speech has not been systematically evaluated. In this study, the speaking fundamental frequency, reading rate, and first and second formants of the vowels of four patients were measured acoustically presurgically and postsurgically. The results indicate that the length of time needed to read a passage was reduced in all four patients 2 weeks following surgery compared to the presurgical duration. In addition, the second formant of nine vowels studied was lower postsurgically. No changes in speaking fundamental frequency were found in three of the four patients; in the fourth, the speaking fundamental frequency was lower by approximately one semitone. Based on the reduced reading rates from the presurgical to the postsurgical conditions, changes in respiratory parameters in addition to vocal tract parameters warrant assessment when evaluating the speech of individuals prior to and following uvulopalatopharyngoplasty.