Objectives of middle-ear research


Ear, nose and throat cartoon

© Joe Kohl

1. Motivation


2. Objectives

Plaster model of ear

3. Hearing loss

Newborn

 

3.1 Newborns


3.2 Adults

4. Screening and diagnostic techniques

Audiogram

4.1 Audiogram


Sources of ABR waves

4.2 Auditory brainstem response

Probst R, Grevers G & Iro H (2006) Basic otolaryngology: A step-by-step learning guide, Thieme, New York, NY
Auditory brainstem response

Threshold determination requires judgement about when waves disappear

Olubunmi V. Akinpelu, McGill University, 2013
OAE diagram
Diagram of OAE measurement

4.3 Otoacoustic emissions


Distortion-product otoacoustic emissions

Comparison of distortion-product amplitude to noise level

4.3.1 Limitations

Automated OAE and ABR screening can detect hearing loss,
but they cannot effectively distinguish between

Large numbers of false positives

4.4 Acoustical input admittance

Input admittance of electrical circuit = I/V

4.5 Tympanometry

Tympanometer
Diagram of a tympanometer

Addition of static pressures

but ...

After Cull (1989): The Sourcebook of medical illustration, Parthenon, Carnforth, xxiii+481 pp.
Infant tympanograms
Tympanograms from 156-day-old infant for three frequencies Right ear (top) was normal, left ear (bottom) had middle-ear effusions and failed hearing screening test
Dark lines = susceptance, light lines = conductance
Units for horizontal axes (static pressure) = daPa, vertical axes = mmho


5. Treatment

5.1 Passive prostheses

Three types of prosthesis

Repair or replacement of the eardrum and ossicles

After Cull (1989): The Sourcebook of medical illustration, Parthenon, Carnforth, xxiii+481 pp.

Smith + Nephew prostheses

Smith + Nephew catalogue

Many different designs


Nitinol stapes prosthesis

www.kurzmed.com

Potential technology is increasingly sophisticated:


Park MS & Min HK (2000): Laser soldering and welding for ossicular reconstruction: an in vitro test. Otolaryngol Head & Neck Surg 122(6): 803-807


but

There has been little systematic analysis of mechanical performance

E.g.,
Slater PW, Rizer FM, Schuring AG & Lippy WH (1997): Practical use of total and partial ossicular replacement prostheses in ossiculoplasty. Laryngoscope 107: 1193-1198
Stupp CH, Dalchow C, Grun D, Stupp HF & Wustrow J (1999): Titan-Prothesen im Mittelohr. 3-Jahres-Erfahrungsbericht. Laryngo- Rhino- Otologie 78(6): 299-303

5.2 Passive external devices

F. C. Rein, ca. 1810

2005-2009 Washington University School of Medicine, Bernard Becker Medical Library

See also The History of Hearing Aids (IEEE, 2013)

5.3 Hearing aids and implants


1940’s 2005-2009 Washington University School of Medicine, Bernard Becker Medical Library

Design and evaluation of active devices

See also The History of Hearing Aids (IEEE, 2013)

6. Inner ear

Diagram of ear

Characterization of stimulus to inner ear

For interpretation of cochlear experiments

Often, the input to the cochlea is characterized by measuring

but the actual cochlear input is determined by the middle ear

After Cull (1989): The Sourcebook of medical illustration, Parthenon, Carnforth, xxiii+481 pp.

7. Teaching

Inner and middle ear

Davis3d project

Teaching of middle-ear anatomy and surgical techniques:

Can teach using



BMDE-501 Modelling middle-ear mechanics

R. Funnell
Last modified: 2018-11-04 22:51:33