Related Experiment Video
Updated: Apr 23, 2026
Modified Experimental Conditions for Noise-Induced Hearing Loss in Mice and Assessment of Hearing Function and Outer Hair Cell Damage
Published on: February 10, 2023
Prolonged noise exposure-induced auditory threshold shifts in rats
Guang-Di Chen1, Brandon Decker1, Vijaya Prakash Krishnan Muthaiah1
1Center for Hearing and Deafness, State University of New York at Buffalo, 137 Cary Hall, 3435 Main Street, Buffalo, NY 14214, USA.
This study establishes a predictive model for noise-induced hearing loss (NIHL) in rats, detailing threshold shifts and auditory brainstem response reductions following noise exposure. Findings reveal permanent hearing deficits and cochlear damage in rats, with critical noise levels comparable to humans.
Area of Science:
- Auditory Neuroscience
- Toxicology
- Occupational Health
Background:
- Noise-induced hearing loss (NIHL) is a significant health concern.
- Predictive models for NIHL asymptotic threshold shift (ATS) exist for some species but not rats.
- Rats are widely used in noise exposure research, necessitating species-specific ATS models.
Purpose of the Study:
- To develop predictive equations for noise-induced hearing loss in rats.
- To quantify the compound threshold shift (CTS) and auditory brainstem response (ABR) changes in rats exposed to noise.
- To establish critical noise levels for hearing damage in rats.
Main Methods:
- Rats were exposed to narrowband noise (16-20 kHz) for 5 weeks, with sound pressure levels increasing weekly from 80 to 104 dB SPL.
- Auditory brainstem responses (ABR) were recorded before, during, and after noise exposure.
- Threshold shifts and ABR peak amplitudes were analyzed to determine noise-induced hearing loss.
Main Results:
- Compound threshold shift (CTS) increased with noise level (NL) at 1.82 dB per dB above a critical level (C) of 77.2 dB SPL: CTS = 1.82(NL-77.2).
- Auditory brainstem response (ABR) peak amplitude reduction was 3.1% per dB above a critical level (C) of 76.9 dB SPL: %ABR Reduction = 3.1%(NL-76.9).
- Permanent threshold shifts of 30-40 dB and significant hair cell loss were observed post-exposure.
Conclusions:
- The rat model demonstrates a compound threshold shift (CTS) that increases with noise level, similar to humans and chinchillas.
- The critical noise level for hearing damage in rats is comparable to humans but higher than in chinchillas.
- This study provides the first predictive equations for noise-induced hearing loss in rats, crucial for future research.
