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Stochastic Noise Application for the Assessment of Medial Vestibular Nucleus Neuron Sensitivity In Vitro
Published on: August 28, 2019
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Noise-dose estimated with and without pre-cochlear amplification
Sarah K Grinn1, Colleen G Le Prell2
1Central Michigan University, Herbert H. and Grace A. Dow College of Health Professions, Mount Pleasant, Michigan 48859, USA.
The Journal of the Acoustical Society of America
|December 5, 2019
Summary
Individual differences in how the ear amplifies sound significantly impact noise-induced hearing loss (NIHL) risk. Understanding the transfer function of the open ear (TFOE) variability is key to personalized NIHL prevention.
Area of Science:
- Audiology
- Occupational Health
- Bioacoustics
Background:
- Natural ear canal resonance amplification varies greatly among individuals.
- Individual differences in pre-cochlear amplification, encompassing external and middle ear functions, are understudied concerning noise-induced hearing loss (NIHL).
- Current NIHL risk models do not account for individual variability in the transfer function of the open ear (TFOE).
Purpose of the Study:
- To document individual variability in the transfer function of the open ear (TFOE).
- To explore simple proxy metrics for estimating TFOE.
- To assess the impact of TFOE variability on estimated NIHL risk.
Main Methods:
- Forty-eight adult participants underwent otoscopy, tympanometry, pinna size measurement, and TFOE measurement.
- TFOE was measured directly, and proxy metrics like eardrum compliance were evaluated.
- NIHL risk was estimated using individual TFOE values in hypothetical free-field noise exposures.
Main Results:
- TFOE exhibited significant individual variability, ranging from 5 to 15 dB-A (mean 10 dB-A).
- This variability can substantially explain differences in NIHL susceptibility between individuals exposed to identical noise levels.
- Eardrum compliance showed a significant correlation with TFOE (p < 0.05) in this cohort.
Conclusions:
- Individual TFOE variability is a critical factor in understanding differential susceptibility to NIHL.
- Eardrum compliance may serve as a feasible proxy for estimating TFOE, particularly in adult female populations.
- Further research is needed to validate eardrum compliance as a TFOE proxy in diverse populations.
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