A non-invasive, objective test of endolymphatic hydrops

Area of Science:

• Neuroscience
• Audiology
• Otoacoustic Emissions

Background:

• Auditory brainstem responses (ABRs) are established for measuring basilar membrane travelling wave velocity (TWV).
• Increased inner ear pressure, characteristic of endolymphatic hydrops, is hypothesized to increase basilar membrane stiffness and TWV.
• ABRs offer a potential objective method for diagnosing endolymphatic hydrops.

Purpose of the Study:

• To investigate the utility of ABRs in measuring TWV for diagnosing endolymphatic hydrops.
• To develop and clinically validate a rapid ABR-based test for assessing TWV abnormalities.

Main Methods:

• Measurement of TWV using ABRs in 10 normal-hearing subjects and 20 Meniere's disease patients.
• Development of a 15-30 minute clinical test involving masked ABRs and wave V latency differences.
• Clinical validation through glycerol dehydration tests and ongoing drug efficacy trials.

Main Results:

• Meniere's patients exhibited normal TWV across most frequencies, except for significantly elevated TWV at 5.7 kHz compared to controls.
• A short-duration clinical test for TWV measurement was developed and validated.
• The technique is being applied in longitudinal studies and drug efficacy trials for Meniere's disease.

Conclusions:

• Elevated TWV at 5.7 kHz in Meniere's patients suggests ABRs can objectively detect endolymphatic hydrops.
• The developed ABR-based test is a promising tool for clinical assessment and monitoring of Meniere's disease.
• Further research is ongoing to evaluate drug efficacy and disease progression using this technique.