This is a retrospective case series study to develop a simple, standard, and more objective tool for speech intelligibility evaluation in Japanese patients following tongue reconstruction after a glossectomy for oral cancer.
Speech samples consisting of a single-sentence utterance plus counting 1 through 10, 5 consonant-vowel pairs (for /t/, /s/, /k/, /g/, /r/, and /p/ groups), and diadochokinesis were recorded by 10 native-Japanese speakers who underwent tongue reconstruction surgery. Five medical personnel rated their speech intelligibility using a visual analogue scale (VAS) for the sentence plus counting sample, and assigned a score of 0–3 for the consonant-vowel pairs and a score of 0 or more for diadochokinesis.
The VAS scores of all 5 raters were positively correlated with each other. The total correlation coefficient between the mean VAS score and total intelligibility score was highest for the consonant-vowel pairs of /t/, /k/, and /r/, indicating speech samples using these pairs best correlated with everyday speech.
On the basis of these findings, the test items for the newly developed evaluation tool, named the TKR Speech Test, were finalized as the /t/, /k/, and /r/ consonant-vowel pairs, each scored 0–3. The TKR Speech Test shows promise as a simple yet accurate tool for speech intelligibility evaluation in Japanese patients following tongue reconstruction surgery.