Hidden Hearing Loss

What is synaptopathy, and how can we diagnose it?

One of the current hot topics in hearing research, is how we diagnose hidden hearing loss, or synaptopathy, in people with hearing impairment.

What is synaptopathy?

Synaptopathy is a disease relating to the dysfunction of synapses, the part of the nervous system that makes sure our neurons can communicate with one another, effectively allowing signals to pass through to the brain from various parts of the body. If synapses are damaged or worn down, they will misfire – or quite simply not trigger – causing missed sensations, or, in the case of hearing, missed noise.

Developing a reliable tool

A typical hearing test will not offer you much insight into problematic synapses or hidden hearing loss in general, and so we need to develop new methods for diagnosing this kind of hearing impairment. 

There is currently no underlying theory as to how hidden hearing loss reveals itself. In this study, we hypothesize that short sounds in noisy environments can indicate an underlying hearing loss, that typical audiograms cannot diagnose. As an example, if you are in a noisy environment, and your synapses – due to wear and tear – cannot distinguish all the noises, parts of the sounds are filtered out.

More research is needed

In a joint research project with Enrique Lopez-Poveda, Peter Johannesen, Byanka Cagnacci Buzo of the University of Salamanca, and James Harte from the Interacoustics Research Unit at the Danish Technical University, we began digging into this very complex problem, to find a reliable way of diagnosing synaptopathy in hearing impairment. We created a customized audiogram, which would play shorter noises than a typical hearing test, and our hypothesis was that while everyone would see a small change compared to their regular audiogram, those suffering from hidden hearing loss would see a much larger change.

On February 11-15, Enrique, Peter and James will visit the ARO conference in Baltimore, to present the results of our study. If you are unable to attend the conference, we will share more information from the study once the conference concludes. We hope to see you there!