Functionality of hearing aids: state-of-the-art and future model-based solutions

Abstract

A review about technical and perceptual factors in hearing aid technology, research and development is provided, covering current commercial solutions, underlying models of hearing loss for usage in hearing devices and emerging future technical solutions for hearing aid functionalities. A chain of techniques has provided incremental, but steady increases in user benefit, e.g. in the fields of hearing aid amplification, feedback suppression, dynamic compression, noise reduction and situation adaptation. The models describing the perceptual consequences of sensorineural hearing impairment describe the effects on the acoustical level, the neurosensory level and the cognitive level and provide the framework for compensatory (or even substitutional) functions of hearing aids in terms of the attenuation component, the distortion component and the neural component of the hearing loss. A major factor is the requirement of a strong individualisation of hearing aid solutions calling for an appropriate assessment of the different sensorineural components of a hearing loss, especially with respect to bilateral and binaural hearing aid solutions.

Key Words:

• Hearing loss
• models of hearing
• compensation strategies
• rehabilitation with hearing aids

Notes

Acknowledgements

Supported by BMBF project “model-based hearing solutions” FKZ 01EZ1127D. Additional support was provided by the Deutsche Forschungsgemeinschaft (Cluster of Excellence 1077 “Hearing4All”). The authors cordially thank all collaborators and partners for their continuing support.

Declaration of interest

BK received payments for invited talks from Sivantos and Sonova and for consulting GNReSound. The authors report no other potential conflict of interest. The authors alone are responsible for the content and writing of this article.

Notes

1. In a physical or communication theory sense, signal processing in the ear can be described by a chain of several signal processing stages that reflect the “effective” processing in the auditory system (which is primarily considered here) while not necessarily taking the actual biological implementation into account. Additionally, physiologic models (Sumner et al, 2002; Zilany et al, 2009, 2014) have gained interest, as they appear suited for a detailed simulation of peripheral hearing loss consequences including effects of a reduced number of available auditory-nerve fibres (Kujawa & Liberman, 2009; Furman et al, 2013) in connection with normal audiograms (concealed or “hidden” hearing loss). Since a direct application of such physiologic models to hearing aid processing and fitting is difficult, this class of models will not be considered here.