# Tympanometric laser Doppler vibrometry measurements of middle ear function

> **NIH VA I21** · PORTLAND VA MEDICAL CENTER · 2020 · —

## Abstract

Laser Doppler vibrometry (LDV) is an emerging technology for assessing middle ear (ME) function that
detects the sound-induced velocity (Vu) of one of the ME bones, the malleus, over a wide frequency range
(300 to 6000 Hz) using a reflected laser beam. The PI seeks to develop LDV measures as a new research
area in line with his previous work in the assessment of ME function using wideband acoustic immittance (WAI)
measurements. Because LDV measures the movement of one of the ossicles, it is inherently sensitive to
ossicular chain disorders such as otosclerosis, and is thus a potentially useful diagnostic tool. LDV obtained at
ambient pressure in the ear canal has been shown to result in similar diagnostic sensitivity to WAI, but has
wide variability. The diagnostic capability of LDV may be enhanced by making measurements at
tympanometric peak pressure (TPP) rather than ambient pressure to control for the effects of varying middle-
ear pressure from test to retest and across subjects. This ME pressure related variability may mask underlying
ME disorders. Moreover, a comparison of Vu at TPP with tympanometric tail pressures (e.g. ±200 daPa) may
provide additional information about the ME status that previously has not been measured. This will be the first
study to evaluate the use of tympanometric (varying ear canal pressure) LDV measures for the assessment of
ME function. Aim 1 is to make the first repeated measures of Vu at TPP and tympanometric tail pressures in
control subjects with normal ME function using a custom ear speculum developed at the VA National Center
for Rehabilitative Auditory Research (NCRAR). These test-retest differences will be compared with
measurements obtained at ambient pressure by fitting a hierarchical Gaussian process regression model to
these data, as well as comparing the data to published test-retest differences for Vu at ambient pressure. Aim
2, using the data from Aim 1, will establish reference limits as a function of frequency for ambient pressure,
TPP, ±100 daPa, and ±200 daPa, and for tympanometric peak-to-tail differences for ±100 daPa and ±200
daPa. In Aim 3 the reference limits established in Aim 2 will be applied to the Vu data obtained from 10
subjects with a diagnosis of otosclerosis for ambient pressure and pressurized measures. A Bayesian
hierarchical regression model will be used to compare mean differences in Vu between the control group and
the otosclerosis group at each of the 9 stimulus frequencies in each test condition.
 Subjects will be recruited using the NCRAR data repository, through approved flyers posted in the VA
Portland Health Care System (VAPORHCS) and handouts provided to patients from audiologists or
otolaryngologists in VAPORHCS clinics. Enrollment in the study is for two study visits for both control subjects
and those with otosclerosis: The first visit involves hearing evaluation and tympanometry as well as
measurements of LDV for both ears at ambient pressure, tympanometric peak ...

## Key facts

- **NIH application ID:** 9922131
- **Project number:** 5I21RX003182-02
- **Recipient organization:** PORTLAND VA MEDICAL CENTER
- **Principal Investigator:** Martin Patrick Feeney
- **Activity code:** I21 (R01, R21, SBIR, etc.)
- **Funding institute:** VA
- **Fiscal year:** 2020
- **Award amount:** —
- **Award type:** 5
- **Project period:** 2019-06-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9922131

## Citation

> US National Institutes of Health, RePORTER application 9922131, Tympanometric laser Doppler vibrometry measurements of middle ear function (5I21RX003182-02). Retrieved via AI Analytics 2026-05-22 from https://api.ai-analytics.org/grant/nih/9922131. Licensed CC0.

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