Effects of genioglossal muscle advancement on speech: an acoustic study of vowel sounds.
The effects of the genioglossal muscle advancement on phonetic quality of speech were studied analyzing the acoustic features of vowel sounds. The study group consisted of 5 men suffering from partial upper airway obstruction during sleep. To prevent tongue base collapse, genioglossal muscle advancement was made with chin osteotomy without hyoid myotomy and suspension. The speech material consisted of 8 vowels produced in sentence context repeated 10 times before the operation, and 10 days and 6 weeks after the operation. The acoustic features of vowels were analyzed. The operation had no significant effects on vowel quality. Only for 2 of the subjects the pitches changed systematically due to the operation. According to the acoustic analysis, genioglossal muscle advancement with chin osteotomy has no effects on vowel production. Some short-term changes were observed, but these changes were highly individual. The operation seems to have no potential to change vowel production.