IS THE TONGUE IS MORE THAN A DENTAL OBSTACLE?

1. IS THE TONGUE IS MORE THAN A DENTAL OBSTACLE? Maureen Stone, Ph.D. Department of OCBS and Orthodontics University of Maryland Dental School Baltimore This research was supported in part by grant DC02561 from the National Institute of Deafness and Other Disorders

2. Goals of Tongue Measurement • Visualize, represent, and predict the complex movements of speech and swallowing.

3. Goals of Tongue Measurement • Visualize, represent, and predict the complex movements of speech and swallowing. • Gain insight into motor control strategies used in speech production and swallowing.

4. Goals of Tongue Measurement • Visualize, represent, and predict the complex movements of speech and swallowing. • Gain insight into motor control strategies used in speech production and swallowing. • Quantify functionally important features of speech gestures.

5. Mel Blanc is the voice of numerous cartoon characters

6. HEAD AND TRANSDUCER SUPPORT SYSTEM (HATS)

7. front back upper surface “It ran a lot” Midsagittal Slice

8. left right upper surface Coronal Slice 1: most anterior

9. Coronal Slice 2

10. Coronal Slice 3

11. Coronal Slice 4

12. Coronal Slice 5: most posterior

13. back front “It ran a lot.” 3D upper surface of tongue.

14. Ultrasound Data Analysis • The midsagittal surface contour was extracted for each frame of each repetition. • An identical number of frames were chosen for all upright and supine repetitions for each word and speaker. This was important for subsequent processing.

15. /o/ /l/ /s/ /A/ front front time time back back Time-motion ‘waterfall’ display of tongue contours “Golly” “Oslo” • time=33 ms between contours. Subject 1, supine /i/ /l/ /A/ /g/ Length (x) Length ()

16. Continuous Swallowing

17. Two Projects • Effect of Anterior Open Bite on Swallowing Mike Noorani, Orthodontics Resident MS Thesis, 2003 • Effect of Mouth Breathing on Tongue Position Shahram Fazilat, 2nd year Dental Student Summer Project, 2002

18. Study 1. Effect of Anterior Open Bite (AOB) on Swallowing Pattern

19. Swallowing is stereotypic and partially reflexive. Large boluses are swallowed more rapidly than small. EPG swallowing patterns are similar for both bolus sizes. (AOB) will have the same effect as a large bolus. Ultrasound swallowing patterns will be similar for both bolus sizes. Known Information Hypotheses

20. Recording Procedures • Open bite was simulated with bite blocks placed between the first molars. • Swallowing was measured for bolus sizes of dry, 5, 10, and 20 ml. • Bite conditions were unrestrained (U), 5mm and 10mm. • Midsagittal ultrasound was collected measured and displayed as a connected waterfall display.

21. Effect of Bite Block Size20 ml water Unrestrained vs. 10 mm Block

22. 3 2 Height Time 1 BACK_ _ _ _ _ _ _ _ _ _FRONT Midsagittal tongue deformation mimics bolus movement. • At first, the bolus depresses the anterior tongue (red). • The bolus is transported backward. • The tongue elevates A-to-P as the bolus is squeezed backward. Unrestrained– 20 ml Blue = high, Red = low regions

23. Unrestrained 10 mm BB Height Height Time Time Time Pos_ _ _ _ _ _ _ _ _ _ _Ant The biteblock caused a more anterior tongue initially (blue), a lower depression during propulsion (yellow), and a more anterior final closure (blue).

24. unrestrained 10 mm BB time The overlay shows the tongue to be anterior and inferior in the BB case. The initial and final closures were more anterior in BB than unrestrained (red arrows). Perhaps the subject could only reach a more anterior (and lower) part of the palate.

25. Effect of Bolus Size:Unrestrained Jaw 5ml vs 20 ml water

26. The patterns are very similar. 20ml 5ml The larger bolus depresses more deeply in the front around the bolus (red). Also the tongue elevates more rapidly to achieve maximum closure.

27. tongue palate contact 5 ml 20 ml time Swallowing patterns were similar for 2 bolus sizes. The 20 ml bolus begins with greater anterior tongue lowering, but both swallows end in the same place, with full palate contact. Thus pattern differences werere primarily scalar.

28. Study 2. Effect of Mouth Breathing on Tongue Position

29. Methods • Tasks • Breathe normally for one minute (NO). • Breathe with nose clamped for one minute (NC). • Breathe with nose clamped and tongue held forward for one minute (NCANT). • Measurements • Ultrasound images of midsagittal tongue contour. • Contour measured as x,y coordinates. • Displayed in Excel.

30. NO NC NCANT Mouth Breathing Results • Subjects 1 and 2 were similar. • NC caused tongue lowering. • NCANT caused anterior tongue position. • Subject 3 was different. • NC caused backward tongue rotation. • NCANT caused anterior tongue root. • All opened their airways more in NCANT than NC.

31. Conclusions • Tongue motion is complex in three dimensions. • Tongue segments are uncorrelated due the tongue’s anisotropic muscle architecture. • Cf: It ran a lot movie . • Study Results • AOB caused anterior (inferior) tongue-palate contact. • Bolus size did not affect swallow pattern; effects were scalar. • Subjects’ responses to blocked airway was variable (N=3).

32. Harmonica Courtesy of Dr. Henry T. Bahnson, MD and Dr James F. Antaki, PhD Department of Surgery at the University of Pittsburgh School of Medicine 1990-1991