The clinical application of acoustic analysis to evaluation of tongue position

Kaori Ishii, Kimiko Yamashita, Katsuhiko Saitoh, Satoshi Horihata, Kazutaka Kasai

Research output: Contribution to journalArticlepeer-review


Tongue thrust is a habit in which the tongue protrudes between the upper and lower anterior teeth and causes malocclusion. Oral myofunctional therapy (MFT) is used to eliminate the habit of tongue-thrust swallowing. In the present study, we investigated changes in the tongue position before and after MFT using acoustic analysis. Twelve patients with tongue thrust who underwent MFT were enrolled. The first formant (F1) and the second formant (F2) of the consonant /∫/ were analyzed. To revise individual differences, F1 and F2 were divided by the fourth formant (F’4) of the vowel /i/. As a result, F1/F’4 and F2/F’4 were significantly lower after MFT than before MFT. Our results suggest that the tongue moves superiorly and posteriorly after MFT, which restores normal swallowing in patients with the tongue thrust habit.

Original languageEnglish
Pages (from-to)1391-1394
Number of pages4
JournalICIC Express Letters, Part B: Applications
Issue number10
Publication statusPublished - 1 Oct 2017


  • Formant
  • Myofunctional therapy
  • Tongue position
  • Tongue thrust


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