Overview of Otoacoustic Emissions

1. Overview of
Otoacoustic
Emissions
CSD 808 Fall 2014

2. History
First publication describing discovery of
otoacoustic emission phenomena in 1978.
Kemp, D. T. (1978). Stimulated acoustic emissions from within the human
auditory system. The Journal of the Acoustical Society of America, 64(5),
1386-1391.
First publication reporting clinical application of
otoacoustic emissions in 1983.
Johnsen, N. J., Bagi, P., & Elberling, C. (1983). Evoked acoustic emissions
from the human ear: III. Findings in neonates. Scandinavian audiology, 12
(1), 17-24.

3. History
OAEs did not become commonplace in clinical
settings until mid-1990s.
At present we have three CPT billing codes for
OAEs.
92558: Evoked otoacoustic emissions, screening (qualitative measurement of distortion
product or transient evoked otoacoustic emissions), automated analysis
92587: Distortion product evoked otoacoustic emissions, limited evaluation (to confirm
the presence or absence of hearing disorder, 3–6 frequencies) or transient evoked
otoacoustic emissions, with interpretation and report
92588: Distortion product evoked otoacoustic emissions, comprehensive diagnostic
evaluation (quantitative analysis of outer hair cell function by cochlear mapping, minimum
of 12 frequencies), with interpretation and report

4. History
Georg von Békésy
●in late 1940s, he described
traveling wave measured in
inner ear of human
cadavers
●awarded Nobel Prize in
Physiology/Medicine in 1961

5. History
Georg von Békésy - traveling wave

6. History
Georg von Békésy
However, frequency-
dependent response
properties of basilar
membrane insufficient in
accounting for
mammalian auditory
sensitivity and frequency-
resolving abilities.

7. History
Thomas Gold
●In 1948, he challenged von
Békésy's theories and posited an
active feedback system in the
cochlea
●His ideas were not given
credence until OAEs were
discovered in the 1970s
●Has a career as an accomplished
astrophysicist

8. History
David Kemp
●British physicist
●discovered OAEs in 1977
●In 1988, purchased patent rights
from British govt. and founded
Otodynamics which produced
the ILO88 OAE system

9. History - Early Clues to
OAEs
Auditory Microstructure

10. History

11. History
-Evolution of OAE as Clinical Tool-
•Newborn hearing screening was first clinical
application
•OAEs were objective and could fairly
accurately separate those with normal hearing
from those with peripheral auditory
dysfunction
•How did OAEs compare with earlier newborn
hearing screening techniques?

12. History
-Evolution of OAE as Clinical Tool-
Early success with OAEs have spawned
thousands of investigations. Are there
relationships between--
○ OAEs and tinnitus?
○ OAEs and hearing threshold?
○ OAEs and noise exposure?
○ OAEs and aging?
○ OAEs and ototoxic drug exposure?

13. Implications of the Active Cochlea
for Clinical Audiology
● The idea of site-of-lesion being broken down
into conductive, sensorineural, and
retrocochlear needs to be expanded
● A purely sensory transmissive loss is
consistent with absent OHCs whereby
detection thresholds are elevated, along
with recruitment, and frequency
discrimination is impaired

14. Implications of the Active Cochlea
for Clinical Audiology
● A purely sensory transductive loss is
consistent with normal OHCs but
concomitant IHC dysfunction resulting in an
elevated auditory nerve action potential
threshold
● How do we differentiate between sensory
transductive and retrocochlear losses?
● A pure sensory transductive loss is rare….
think Audtory Neuropathy Spectrum
Disorder

15. Intro to A&P in OAE
Measurement

16. OAE Equipment
laptop-based units

17. OAE Equipment
All in one handheld units

18. OAE Equipment
All in one handheld units