Introduction

The goal of amplification, who benefits, and the spectrum of devices — from a behind-the-ear hearing aid to a cochlear implant — that this atlas covers.

Why amplify

Hearing loss is one of the most common chronic conditions worldwide, and most of it is treatable with devices that are under-used: a large share of people who would benefit from a hearing aid do not have one[14]. Untreated hearing loss is not benign — it is associated with social isolation and, in older adults, with poorer cognitive trajectories, which strengthens the case for timely, effective amplification [15]. The aim is not merely to make sound louder, but to restore audibility of speech across frequencies while keeping loud sounds comfortable.

The amplification spectrum

Devices form a spectrum matched to the degree and type of loss. For most sensorineural losses, an air-conduction hearing aid is first line, and modern aids serve mild through to severe and many profound losses [1]. When a hearing aid cannot deliver enough benefit — or the ear cannot be aided conventionally — implantable options take over: bone-conduction devices for conductive or mixed losses and single-sided deafness[12], middle-ear implants, and, for severe-to-profound sensorineural loss with limited aided benefit, the cochlear implant [13].

How this atlas is organised

The first chapters build the hearing aid from the outside in — its styles and components, the signal processing that shapes sound, the prescription that sets the targets, and the verification that proves the fitting meets them. The final chapter steps beyond the hearing aid to the implantable spectrum. Use the Reading level control in the sidebar to switch between Foundation, Trainee and Clinician depth.