To assess, in patients undergoing glossectomy, the influence of the palatal augmentation prosthesis on the speech intelligibility and acoustic spectrographic characteristics of the formants of oral vowels in Brazilian Portuguese, specifically the first 3 formants (F1 [/a, e, u/], F2 [/o,ó, u/], and F3 [/a,ó/]).
Speech evaluation with and without a palatal augmentation prosthesis using blinded randomized listener judgments.
Tertiary referral center.
Thirty-six patients (33 men and 3 women) aged 30 to 80 (mean [SD], 53.9 [10.5]) years underwent glossectomy (14, total glossectomy; 12, total glossectomy and partial mandibulectomy; 6, hemiglossectomy; and 4, subtotal glossectomy) with use of the augmentation prosthesis for at least 3 months before inclusion in the study.
Main Outcome Measures
Spontaneous speech intelligibility (assessed by expert listeners using a 4-category scale) and spectrographic formants assessment.
We found a statistically significant improvement of spontaneous speech intelligibility and the average number of correctly identified syllables with the use of the prosthesis (P < .05). Statistically significant differences occurred for the F1 values of the vowels /a, e, u/; for F2 values, there was a significant difference of the vowels /o,ó, u/; and for F3 values, there was a significant difference of the vowels /a,ó/ (P < .001).
The palatal augmentation prosthesis improved the intelligibility of spontaneous speech and syllables for patients who underwent glossectomy. It also increased the F2 and F3 values for all vowels and the F1 values for the vowels /o,ó, u/. This effect brought the values of many vowel formants closer to normal.