Coronal view ultrasound imaging of movement in different segments of the tongue during paced recital: findings from four normal speakers and a speaker with partial glossectomy.

The goal of this study was to quantitatively describe aspects of coronal tongue movement in different anatomical regions of the tongue. Four normal speakers and a speaker with partial glossectomy read four repetitions of a metronome-paced poem. Their tongue movement was recorded in four coronal planes using two-dimensional B-mode ultrasound imaging. Quantitative indicators of tongue function (total distance travelled and concavity) were calculated. In all participants, it was observed that the centre of the tongue travelled greater distances than the lateral free margins. The tongues of the female speakers F1 and F2 travelled greater distances than those of the males M1 and M2. The greatest distances travelled were observed in the speaker with partial glossectomy G. In three of the participants, the greatest cumulative distances were recorded for the anterior tongue (F1, M1, and G) and in the other two (F2 and M2) in the posterior tongue. The concavity measure illustrated that the posterior tongue showed consistent grooving during connected speech, in all speakers. Flatness or convexity of the tongue was mainly observed in the anterior tongue. The study provides the first quantitative description of coronal tongue movement in a complex speech passage. Future research will have to further examine the effects of gender and orofacial morphology on the coronal shape and movement of the tongue.