Overview of Otoacoustic EmissionsCSD 808 Fall 2014

HistoryFirst 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.

HistoryOAEs 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

HistoryGeorg von Békésy

●in late 1940s, he described traveling wave measured in inner ear of human cadavers

●awarded Nobel Prize in Physiology/Medicine in 1961

HistoryGeorg von Békésy - traveling wave

HistoryGeorg von Békésy

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

HistoryThomas 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

HistoryDavid Kemp

●British physicist

●discovered OAEs in 1977

●In 1988, purchased patent rights from British govt. and founded Otodynamics which produced the ILO88 OAE system

History - Early Clues to OAEsAuditory Microstructure

History

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?

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?

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

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

Intro to A&P in OAE Measurement

OAE Equipment

laptop-based units

OAE Equipment

All in one handheld units

OAE Equipment

All in one handheld units