A 3D computational model framework of the stimulated peripheral auditory system

Authors: Yixuan Zhang1, Franklin Alvarez Cardinale2, Daniel Kipping1, Waldo Nogueira3

1Hannover Medical School
2Medizinische Hochschule Hannover
3Medical University Hannover, Cluster of Excellence Hearing4all

Background: Cochlear implants (CIs) stimulate the auditory nerve fibers (ANFs) inside the cochlea and partially restore hearing in people with sensorineural hearing loss by providing an audible sound percept. Computational models can be used to simulate both the electrical field pattern and spike generation in ANFs with electric and acoustic stimulation. This work combines 3D volume geometries with numerical simulation to investigate the underlying mechanisms of the electrically and acoustically stimulated auditory system.

Methods: A 3D computational modeling framework of the peripheral auditory system was created based on histological data at the Hannover Medical School. It consists of i) a 3D FEM model of the cochlea where the voltage distribution and current density can be estimated given a stimulation current; ii) a population of modeled ANFs that can be acoustically and electrically stimulated and can represent different neural health conditions; iii) a collection of algorithms that predict electrophysiological and behavioral responses of CI subjects from the neural activity of the ANF population.

Results and Conclusions: This modeling framework aims to improve our understanding of cochlear stimulation by electric and acoustic stimuli, with possible implications for the clinical fitting of CI patients and surgical procedures. Potential applications of this computational framework include the objective assessment of hearing thresholds through the resulting compound action potential (CAP) via either acoustic stimulation (aCAP) or electric pulses delivered through the CI (eCAP), neural health condition estimation, or prediction of perceptual tasks such as loudness perception or even as amplitude modulation detection and speech recognition.