Hidden hearing loss (Photo: Colourbox)

New knowledge to help people with hidden hearing loss

Tuesday 16 Jan 18


Torsten Dau
Head of Sections, Professor
DTU Health Tech
+45 45 25 39 77
Exposure to loud noise in the environment is causing nerve damage in the ears of ever more people. New research will enable diagnosing and treating such hearing loss in future.

DTU is heading a new research project in collaboration with Harvard Medical School, among others. The purpose of the project is to highlight the growing problem of hearing loss caused by the loud noises to which we are exposed to in our daily lives—for example from traffic, construction sites, and music.

“It was previously thought that exposure to loud noise wasn’t harmful, but merely caused temporary hearing loss. However, scientists at Harvard Medical School have recently demonstrated that loud noise impacts, e.g. at rock concerts, can result in permanent impairment of our hearing,” explains Professor Torsten Dau, DTU Electrical Engineering, who is heading the new project.

Today, this type of hearing loss cannot be detected by an ordinary clinical hearing test, which is why it is referred to as a hidden hearing loss. The problem is growing—the WHO points out that 1.1 billion teenagers and young adults will be at risk of developing hearing loss or tinnitus in future because modern life is exposing us to too many loud noises on a daily basis.

Multidisciplinary approach ensures necessary synergies
The new research project will include several different research disciplines to create the necessary synergies to be able to create a breakthrough. Harvard Medical School will contribute their expertise about the physiology of the damaged ear, based among other things on animal testing. In Denmark, the Danish Research Centre of Magnetic Resonance (DRCMR) at Hvidovre Hospital will conduct MRI scans of the auditory nerve and auditory structures in the brain to gain knowledge about changes to the damaged cells.

"The new research project will include several different research disciplines to create the necessary synergies to be able to create a breakthrough"

DTU will combine the knowledge gained in this process with audiological and physiological measurements of persons exposed to noise in order to develop methods for diagnosing this particular type of hearing loss. DTU will also develop detailed models of the inner ear based on data from the various parts of the project to be used to predict where and how hearing loss happens.

“The initial challenge is to develop a method for measuring hidden hearing loss, which is not possible with the existing clinical hearing tests. To do this, we need greater insight into the brain’s sound perception. We don’t know why the damaged synapses in the ear make it difficult for the brain to decode speech in noisy environments, for example, while the person’s hearing is otherwise normal,” says Torsten Dau.

“Once we’ve found out how the brain reacts to the damage to the synapses in the ear, we’ll be able to develop a method for measuring hidden hearing loss at an early stage. And once a method for ensuring correct diagnosis by means of a test is in place, others will be able to develop medicine to mitigate the hearing loss,” says Torsten Dau.

Thus, the new research will potentially be hugely beneficial to the many people who will come to suffer from hidden hearing loss in the future, and indeed whose lives are already inhibited by this condition. 

The Novo Nordisk Foundation has granted EUR 2 million (DKK 15 million) to the project. The grant comes from the foundation’s Interdisciplinary Synergy Programme, which provides funding for innovative interdisciplinary research. The background for the programme is that many health-related challenges and issues cannot be resolved a through a traditional unidisciplinary approach.

Facts: Concealed hearing loss


Hidden hearing loss, adapted from C. Liberman, Scientific American, 2015