# ORIGINS OF PHYSIOLOGICAL MEASUREMENTS FROM THE EAR

> **NIH NIH R01** · WASHINGTON UNIVERSITY · 2020 · $324,063

## Abstract

Acoustic and electrical measurements from normal and diseased ears have many uses but their origins are not
fully understood. This work proposes to identify the origin of several objective auditory responses in ears with
and without hearing loss. Transient-evoked otoacoustic emissions (TEOAEs) are widely used to screen for
hearing loss in neonatal well-baby nurseries. Stimulus frequency otoacoustic emissions (SFOAEs) are widely
used as a non-invasive measurement to study cochlear mechanics. Despite progress, there is controversy on
where in the cochlea TEOAEs and SFOAEs originate. Aims 1 & 2 will definitively identify the origin along the
cochlea of TEOAEs and SFOAEs. Our novel approach is to progressively ablate responses along the cochlear
length by slowly injecting ototoxic pharmaceuticals into the cochlear apex. This will provide what no other
method has been able to do: remove emission contributions from an OAE’s characteristic frequency (CF) place
without removing any OAE components that originate far basal (an octave or more higher) of the CF place.
The work of Aim 1 & 2 will improve the interpretation of TEOAE-based screening protocols, and advance the
understanding of SFOAEs and what they tell us about cochlear tuning and the cochlear amplifier. Aim 3 will
study low-frequency sensorineural hearing loss in ears with endolymphatic hydrops. Low-frequency
sensorineural hearing loss and endolymphatic hydrops are hallmarks of Ménière’s disease that is the focus of
high scientific and clinical interest. Our approach uses a new technique that provides an objective measure of
low-frequency hearing: the Auditory Nerve Overlapped Waveform (ANOW). ANOW overcomes the longstanding
obstacle that conventional electrophysiologic measurements (e.g. otoacoustic emissions and
compound action potentials) do not work adequately below ~1 kHz where hearing loss in Ménière’s disease
occurs. ANOW can detect dysfunction from acute cochlear fluid manipulations that is not detected by
conventional measurements, suggesting that ANOW can detect the earliest stages of chronic endolymphatic
hydrops. Aim 3 will use ANOW to identify early stages of dysfunction from endolymphatic hydrops before the
pathology progresses and can be detected with conventional measures. The proposed studies will expand the
knowledge of the origins of physiologic measurements of otoacoustic emissions and hearing loss that is
needed to advance basic science studies of cochlear mechanics and clinical diagnosis of hearing loss.

## Key facts

- **NIH application ID:** 9831632
- **Project number:** 5R01DC014997-05
- **Recipient organization:** WASHINGTON UNIVERSITY
- **Principal Investigator:** Jeffery Lichtenhan
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $324,063
- **Award type:** 5
- **Project period:** 2016-01-01 → 2021-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9831632

## Citation

> US National Institutes of Health, RePORTER application 9831632, ORIGINS OF PHYSIOLOGICAL MEASUREMENTS FROM THE EAR (5R01DC014997-05). Retrieved via AI Analytics 2026-05-26 from https://api.ai-analytics.org/grant/nih/9831632. Licensed CC0.

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