Inner-hair-cell induced hearing loss: A biophysical modeling perspective

In recent years, experimental studies have demonstrated that malfunction of the inner-hair cells and their synapse to the auditory nerve is a significant hearing loss (HL) contributor. This study presents a detailed biophysical model of the inner-hair cells embedded in an end-to-end computational model of the auditory pathway with an acoustic signal as an input and prediction of human audiometric thresholds as an output. The contribution of the outer hair cells is included in the mechanical model of the cochlea. Different types of HL were simulated by changing mechanical and biochemical parameters of the inner and outer hair cells. The predicted thresholds yielded common audiograms of hearing impairment. Outer hair cell damage could only introduce threshold shifts at mid-high frequencies up to 40 dB. Inner hair cell damage affects low and high frequencies differently. All types of inner hair cell deficits yielded a maximum of 40 dB HL at low frequencies. Only a significant reduction in the number of cilia of the inner-hair cells yielded HL of up to 120 dB HL at high frequencies. Sloping audiograms can be explained by a combination of grad-ual change in the number of cilia of inner and outer hair cells along the cochlear partition from apex to base. (C) 2023 Acoustical Society of America. https://doi.org/10.1121/10.0017627

Automated summary

In recent years, experimental studies have shown that dysfunction of the inner-hair cells and their synapse to the auditory nerve is a significant contributor to hearing loss. This study presents a detailed biophysical model of the inner-hair cells in the auditory pathway, with the input as an acoustic signal and the output as the prediction of human audiometric thresholds. Different types of hearing loss were simulated by altering mechanical and biochemical parameters of the inner and outer hair cells. The results provide a common understanding of various hearing impairments.