1. Adjustable Wave Tube Stand for Acoustic Reflection Technique
Team Leader – Ryan Carroll
Communicator – Jeremy Glynn
BWIG – Andrew Bremer
BSAC – Ben Engel
Client – Erin Douglas CCC/SLP
Advisor – Professor Willis Tompkins Ph.D

2. Overview Background Information Proposal/Client Requirements
Design Alternatives by Component
Design Matrices
Future Work
Questions

3. Background Information
Acoustic Reflection Technique
Non-invasive assessment of vocal tract anatomy
Subjects exhale through wave tube
Microphone captures acoustic reflections of airway
System constructs plots of vocal tract area and distance from lips

4. Background Information
Why study the vocal tract?
To track anatomical changes during growth
To study speech changes/impediments
To study functional abnormalities of the pharynx
To better understand sleep disorders associated with the VT such as sleep apnea

5. Background Information
Goal of current study:
Compare accuracy of measurements from ART to measurements from imaging
Why not just use imaging?
Too expensive
Limits the range of subjects
Cannot be transported to the home
(Durtschi, 2007)

6. Background Information
Major problem with the current protocol
Wave tube device is not in a fixed position
Changes in wave tube position cause:
Change in VT volumes
Problems with repeatability between tests

7. Client Requirements Standard Alignment Large Range of Adjustment
Fine Adjustability
Easily Disinfected
Portability
Non-invasive to patient

8. Design Matrix Feature Ideas Interface Fastening Mechanism Velcro
Rubber Strap
Latch
Gripping Lining
Silicone
Foam
Rubber
Base Material
HDPE
Delryn
Aluminum
LDPE
Stand
Method of adjustment
Perforated tube /pin
Twist and Lock
Gear and track
Joints
Rigid
Adjustable

9. Fastening Mechanism Criteria Weight Velcro Rubber Strap Latch
Security of Wave Tube .4 7 9 5
Ease of Disinfecting .3 2 8
Ease of Manufacturing .2 3
Cost .1
Total
1.0
5.9
8.4
5.8

10. Gripping Lining Criteria Weight Silicone Foam Rubber
Ease of Disinfecting
.35 6 1 9
Relative Tackiness
.25 7
Durability 2
Cost
.15 5 8
Total
1.0
6.6
3.55
8.2

11. Base Material Criteria Weight HDPE Delrin Aluminum LDPE .45 8 5 3
Ease/Quality of Manufacturing
.25 6 4
Cost .3 2 9
Total
1.0
7.5
6.15
3.95
7.3

12. Method of Adjustment Criteria Weight Perforated tube / pin
Twist and Lock
Gear and track
Repeatability .3 10 8 6
Collapsibility .2 9 7
Ease of Use
Fineness of Adjustment 2
Total
1.0
6.4
8.8
7.2

13. Joints Criteria Weight Rigid Adjustable Ease of Use .2 9 6 Portability.4 3
Repeatability 8
Total
1.0
6.6
8.0

14. Future Work Obtain parts for interface construction
HDPE
Rubber gripping interface
Rubber Straps
Build working prototype
Machine base out of HDPE
Assemble all other parts

15. Future Work Patient testing and analysis
Modify Samson MB1 Mini Boom Stand
Place markings on stand for ease of use and reduction of variables between patients and studies
Replace interface with one compatible with wave tube
Patient testing and analysis

16. Questions?

17. References
Durtschi, R. (2007, June, 22). A Comparison of Measurements: Acoustic Reflective Technique vs. Medical Imaging. Retrieved October 13, 2007.
Hoffstein, V. (1991).The acoustic reflection technique for the non-invasive assesment of upper airway area . European Respiratory Journal. 4,
Kamal, I. (2004).Test-retest validity of acoustic pharyngometry. Otolaryngology - Head and Neck Surgery ,
Rubinstein, I (1987).Effect of mouthpiece, noseclips, and head position on airway measured by acoustic reflection technique. Journal of Applied Physiology. 63-4,
Samson Audio. Retrieved October 18, 2007, from MB1 Mini Boom Stand Web site:
Rubber and Foam Film. Retrieved October 11, 2007, from McMaster Web site:
Plastic Sheets, Bars, Strips and Cubes. Retrieved October 11, 2007 from McMaster Web site: