MULTISCALE COCHLEAR BIOMECHANICAL MODELLING AND THE ENVIRONMENTAL AUDITORY RISK INDEX (EARI) AS QUANTITATIVE FORENSIC MARKERS OF ENVIRONMENTAL NOISE EXPOSURE

This repository contains the computational models, simulation outputs, and derived metrics associated with the study “Multiscale Cochlear Biomechanical Modelling and the Environmental Auditory Risk Index (EARI) as Quantitative Forensic Markers of Environmental Noise Exposure.”

Environmental noise is a frequent source of forensic disputes involving occupational exposure, neighbourhood conflicts, and environmental crimes. Despite robust epidemiological evidence linking noise exposure to auditory dysfunction, forensic assessments typically rely on sound pressure level records and subjective reports, with limited incorporation of inner-ear biomechanical or neurophysiological indicators.

To address this gap, this repository provides a multiscale in silico cochlear modelling framework implemented in MATLAB, integrating:

• A one-dimensional transmission-line model of basilar membrane mechanics;

• A three-dimensional finite-difference time-domain (FDTD) fluid–structure interaction model of cochlear hydromechanics;

• A neuromorphic auditory-perceptual pipeline, including ERB-spaced filterbanks, inner hair cell transduction, and stochastic auditory nerve spiking.

Simulations were conducted using harmonic sweeps and speech-like stimuli under two conditions: a quiet control environment (30 dB SPL) and a representative environmental noise exposure (85 dB SPL). The resulting outputs include basilar membrane displacement profiles, tonotopic response maps, cochleogram heatmaps, and auditory nerve spike rasters.

These outputs were normalised and integrated into a composite quantitative metric — the Environmental Auditory Risk Index (EARI) — designed to translate environmental sound-level evidence into physiologically grounded indicators of cochlear overload and neural distortion. The index classified the 85 dB exposure condition as high auditory risk relative to the control condition.

Overall, this repository supports reproducible forensic environmental acoustics, offering a mechanistic bridge between acoustic measurements and simulated inner-ear responses. The materials are intended for use by researchers, forensic experts, policymakers, and clinicians interested in objective auditory risk assessment, expert testimony, and preventive strategies for occupational and community noise control.