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Wideband tympanometry patterns in relation to intracranial pressure
Sandra Gonzalez Torrecilla1, Paul Avan2
1Neurosensory Biophysics Laboratory, University Clermont Auvergne, France.
Hearing Research
|July 23, 2021
Summary
Wideband tympanometry can noninvasively measure intracranial pressure (ICP) by analyzing middle-ear mechanics. This method uses ear absorbance measurements to estimate ICP, potentially offering a new diagnostic tool.
Area of Science:
- Otoacoustic Emissions
- Auditory Physiology
- Medical Instrumentation
Background:
- Conventional tympanometry uses a single frequency, limiting middle-ear analysis.
- Wideband tympanometry (WBT) offers a more comprehensive assessment of middle-ear mechanics.
- Intracranial pressure (ICP) influences middle-ear system mechanics, particularly the stapes-annular ligament.
Purpose of the Study:
- To investigate the sensitivity of WBT to changes in middle-ear stiffness related to ICP.
- To explore the potential of WBT for noninvasive ICP monitoring.
- To establish a relationship between WBT parameters and ICP.
Main Methods:
- Sixty-eight ears were tested using a commercial WBT device (0.25–3 kHz).
- Measurements were taken in various body postures (upright, supine, head-down) to alter ICP.
- Ear canal pressure and energy absorbance were recorded, and tympanometric peak pressure (TPP) was determined.
Main Results:
- TPP varied with posture, becoming more positive in supine (+19 daPa) and head-down (+27 daPa) positions.
- WBT energy absorbance plots shifted along the pressure axis with TPP, indicating ICP effects.
- A relationship ICP ≈ 15 TPP was proposed, linking ICP to TPP under quasi-static conditions.
Conclusions:
- Wideband tympanometry effectively reflects changes in middle-ear mechanics due to ICP variations.
- The middle ear, analyzed via WBT, may function as a 'precision scale' for noninvasive ICP assessment.
- This technique holds promise for developing novel, noninvasive methods for monitoring intracranial pressure.
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