Phonologic and Acoustic Analysis of Speech Following Glossectomy and the Effect of Rehabilitation on Speech Outcomes

Purpose Changes in acoustic features in the perioperative phase for elucidating the mechanisms of articulation disorder and the effect of perioperative rehabilitation were studied prospectively. Materials and Methods Sixty-two patients with 62 tongue cancer were divided into a partial glossectomy group (n = 40) and a reconstruction group (n = 22). Acoustic characteristics were analyzed during the preoperative and postoperative periods and after rehabilitation using the first and second formants of the vowels /a/, /i/, and /u/; the triangular vowel space area (tVSA); and the slopes of formant transitions. Results In the 2 groups, decreases in the tVSA and formant slopes were found from the preoperative to the postoperative period, and the acoustic characteristics of the reconstruction group especially improved to preoperative values after rehabilitation. Analysis of the postoperative period showed that acoustic characteristics were altered at the site of surgical resection. Conclusion Changes of acoustic variables are related to excision size and site, suggesting the distinctive tongue portion for the articulation of each speech sound. Perioperative rehabilitation could activate the articulators and increase the range of movement of the remaining tongue, especially the preserved anterior tongue.