Home

Discovery of inner ear function may improve diagnosis of hearing impairment

10 October 2018

Eva Bergstedt

Results from a research study published in Nature Communications show how the inner ear processes speech, something that has until now been unknown. The authors of the report include researchers from Linköping University.

Ear of a small newborn child close-up. A little hair os visible too Photo credit IstockA collaboration between researchers in Sweden, Denmark, the US, the UK and India has now revealed how the inner ear processes speech. The discovery is an important addition to our understanding of how the inner ear and our sense of hearing function. The results have been presented in an article published in the scientific journal Nature Communications.

“The sound of speech has two components in the inner ear. One component consists of high frequency variations in the sound. The other component, known as the ‘envelope’, describes the outermost shape of the sound of speech”, says Anders Fridberger, professor of neuroscience at Linköping University, and one of two principal authors of the article.

Coding of speech-like sound


Anders Fridberger Photo credit Thor BalkhedThe envelope, which varies relatively slowly, can be considered as the overall structure of the speech signal. Researchers have previously shown that the envelope is most important for understanding what someone is saying.

“But until now we have not known how the inner ear decodes the envelope of the speech signals. This is the new result we are presenting”, says Anders Fridberger.

The inner ear produces tiny electrical currents whenever sound enters – it converts sound to electrical impulses. These are led through the auditory nerve to the brain. By placing small electrodes into the ear canal of experimental subjects, and placing electrodes close to the cochlea of patients who have undergone surgery, the researchers have been able to record the way in which the inner ear codes speech-like sound.

Characteristic electrical signals

LiU researchers in collaboration with an international research team are investigating how the inner ear functions. Photo credit Thor BalkhedThe results have led the researchers to the understanding that speech gives rise to a particular form of electrical signals sent to the brain. These signals differ from those that arise in response to other forms of sound.

“This is both remarkable and surprising”, says Anders Fridberger.

Understanding inner ear function

The discovery is an important addition to our understanding of how the inner ear functions. The inner ear is embedded in a large bony structure, which makes it difficult to access and study it. Thus, diagnosing the exact location of damage to the inner ear is currently difficult.

“We believe that our results will improve diagnostic procedures for various hearing impairments, something that is sorely needed. Much remains to be done, however”, cautions Anders Fridberger.

Nature Communications

Translation: George Farrants

 


Contact

Photo of Anders Fridberger

Anders Fridberger

Deputy Dean, Professor

Related research

New discovery on how the inner ear works

Researchers have found that the parts of the inner ear that process sounds such as speech and music seem to work differently than other parts of the inner ear. Researchers from Linköping University are part of the team behind the discovery.

Auditory neuroscience group

To study the function of these stereocilia, the research group has developed a new type of confocal microscope that makes it possible to directly observe sound-evoked motion.

Latest news from LiU

Alex Enrich Prast in Amazon forest.

Woody surfaces oftrees remove methane from the atmosphere

It is well-known that trees help the climate by taking carbon dioxide out of the atmosphere. But it is now clear that trees have another important role to play.
A person smiles.

LiU alumni help the industry save energy – and money

He left a high-paid job in the gas and oil industry in India for a master’s programme at LiU. Sajid Athikkay does not regret his U-turn. He now runs a company in Linköping that helps industries track and save energy.
A man in a suit holds a green plant in his hand.

LiU involved in a megastudy on climate behaviour

What is the best way to make people behave in a more climate-friendly way? Researchers at Linköping University and Karolinska Institutet have contributed to a worldwide study on this topic.

Tags