Objectives of middle-ear research

Ear, nose and throat cartoon

© Joe Kohl

1. Motivation

2. Objectives

Plaster model of ear

3. Diagnosis



Noninvasive diagnosis, especially for screening of newborns

3.1 Current screening techniques

Sources of ABR waves

3.1.1 Auditory brainstem response

Sources in cochlea, auditory nerve and brainstem.

Measured using surface electrodes.

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
Distortion-product otoacoustic emissions

3.1.2 Otoacoustic emissions

Kemp, 1978

Due to non-linearities, mainly in outer hair cells of cochlea

3.1.3 Limitations

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

Large numbers of false positives
Input admittance of electrical circuit = I/V.

Possibility of differential diagnosis by acoustical input admittance of middle ear

but ...
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.

4. Treatment

4.1 Passive prostheses

Three types of prosthesis
Smith + Nephew prostheses

Smith + Nephew catalogue

Nitinol stapes prosthesis


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


There has been little systematic analysis of mechanical performance.

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

4.2 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)

4.3 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)

5. 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.

6. 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: 2016-11-02 18:22:26