Auditory Neuropathy (AN) – also known as Auditory Neuropathy Spectrum Disorder (ANSD) – is a type of hearing problem that involves the electrical signal passing from the ear to the brain.
Neural (nerve) function can be affected in a number of ways, but the common outcome is a disruption of the timing of the electrical impulses. This results in distortion of sound and listeners often report that they “can hear but can’t understand what is being said to them”.
The most common form of AN is present from birth and occurs as a result of trauma. Babies with breathing problems and/or severe jaundice are particularly at risk. Progressive forms of AN also exist, and these are often related to generalised neurologic diseases, such as Friedreich Ataxia and Charcot-Marie-tooth Disease, which affect a range of neural systems.
Associate Professor Gary Rance provides a basic overview about AN in the interview below. He is an audiologist, a full-time researcher and teacher at the University of Melbourne’s Department of Audiology & Speech Pathology. Click on the play button below to hear the interview.
Symptoms of Auditory Neuropathy
Disruption of the firing patterns in the hearing nerve makes the perception of complex signals, such as speech, difficult. Listening in background noise is particularly affected. Localisation skills, which is the ability to judge where sounds are coming from, may also be affected.
Diagnosing AN can initially be challenging, as people with the condition can have perfectly normal detection of sound.
As a result, tests that measure the function of the nerve and auditory pathways are required. These assessments are carried out routinely in babies, as part of Universal Newborn Hearing Screening programs, but are not standard in adult hearing tests.
In some cases, particularly in children who have the neonatal form of AN, the fitting of Hearing Aids can help by making sound and speech more audible. In other situations, Cochlear Implants can also provide some benefit by bypassing the regions in the auditory system that are damaged.