2. Simulation of a Cochlear Model as a Descriptive Tool for Normal and Abnormal Auditory Functioning Miriam Furst-Yust Azaria Cohen, Vered Weisz, Noam Elbaum, Yaniv Halmut, Dan Mecrantz, Oren Bahat, and Udi shtalrid Dept. of Electrical Engineering-Systems Tel Aviv University

3. Clinical Audiometric Tests Audiograms Speech Discrimination Tests Otoacoustic Emissions

4. Audiometric Diagnosis Conductive or Sensorineural Hearing Loss Cochlear or Retrocochlear Hearing Loss Inner Hair Cells or Outer Hair Cells Loss ? The amount of Outer hair Cell Loss ?

5. Can a Cochlear model help in Audiometric Diagnosis ?

6. The Ear

7. Traveling Waves Tonotopic map of the Cochlea

8. Basilar Membrane Motion + Outer Hair Cells Amplification Outer Hair Cell

9. Cochlear Model One dimensional model Based on fluid dynamics

10. Outer Hair Cell Model Electromotile model OHC adds to basilar membrane pressure

11. Middle Ear Model Oval window Piston based model Outer earMiddle ear microphone Incudostapedial joint TM

12. Cochlear Model Equations Non Linear OHC motility Non Linear Basilar Membrane Motion OHC Index

13. Boundary & Initial Conditions Otoacoustic Emissions

14. Cochlear Representations of Tones Cochlear representation

15. Cochlear Representation of Chirp INPUT OUTPUT Input Signal : Chirp 1-3 KHz Normal Cochlea OHC Loss

16. Cochlear Representation of a click Stapes Apex Stimulus 100u s Healthy CochleaOHC Loss

17. Representation of a word Input Signal: The word “SHEN” INPUT OUTPUT Normal Cochlea OHC Loss

18. Cochlear Representation of a Noisy Word Input Signal: The word “SHEN” with Noise INPUT OUTPUT Normal Cochlea OHC Loss

19. Otoacoustic Emission

20. Introducing cochlear “ roughness ”

21. Model Prediction: Excitation Patterns Normal Cochlea No Active Outer Hair Cells Damaged Cochlea

22. Estimated Audiograms Normal OHC activity Partial damaged OHC No OHC activity

23. Estimated Audiograms

24. Simulated Audiograms Partial OHC activity with “roughness” Normal OHC activity with “roughness”

25. Damaged cochlear response

26. Partial OHC Loss Measured Audiogram Model Prediction

27. Non Linear Properties

28. Equal Loudness Countours

29. Non Linear Respomse טון בודד – פילטרים D=2.3cm CF=488Hz D=1.8cm CF=1074Hz

30. Basilar Membrane Gain

31. Response to Two Tones: Combination Tones TimeFrequency Input = 2kHz + 2.44kHz; Equal level Healthy Cochlea