Eye-opening research offers a vision for the future of audiology

By Kathy Costa, Senior Product Manager, Oticon Inc.

Romantics claim that they can tell if you are in love by simply looking into your eyes. Researchers at the Eriksholm Research Centre, part of Oticon, and the VU University Medical Center in Amsterdam didn’t attempt to validate the “look of love” hypothesis. But they did discover something in the eyes that can support hearing aid technology with the potential to improve the lives of the millions of people worldwide who experience hearing loss.

How hard does your brain work to listen?

Hearing in noise is one of the biggest problems for people who are hard of hearing. Luckily, hearing aid technology has made impressive advances to improve this by removing the noise and focusing on the speaker. A standard measurement of how well you hear with your hearing aids is speech intelligibility - the ability to understand words spoken in a sentence. With advanced technology hearing aids, speech understanding for many people is in the 95% to 100% range so that even with a hearing loss you are able to hear what is being said by the person in front if you focus on this particular person.

Even with advanced hearing aid technology, however, life in the real world is a challenge. We all know how difficult it can be to hear all conversations around a dinner table or just at a small table in a noisy restaurant. If you have a hearing loss, it’s even harder. Your brain is working hard to process what is being said, and it’s actually working very hard even if you can understand all words.  The listening effort required to keep up with the conversation can be exhausting.
Is there a way to assess how hard your brain has to work to understand speech in different environments such as around the dinner table? And could that knowledge measure and support optimizing the newest hearing technology?

An eye-opening discovery

To answer those questions, Eriksholm and VU University Medical Center researchers embarked on an EU-funded project built on the expertise in pupillometry of Dr. Sophia E. Kramer of the VU University Medical Center.  Pupillometry is a well-recognized way to measure pupil dilation. The work on pupillometry and cognitive load began with the work of the Noble-prize winning researcher, Daniel Kahneman back in 1973. Today, a body of evidence has shown that pupil size reflects changes in mental effort. The more challenging the task, the larger the pupil.
The researchers have made an eye-opening discovery: When we pay attention to sound, the muscles in the eyes contract and release based on listening effort. A valuable new way to assess strain on the brain’s processing power when trying to understand speech has been identified! Using pupillometry, researchers can now measure the effort people exert to understand what is being said in a variety of real world listening environments. 

 Easier on the brain

The research findings are already impacting the world of audiology. Oticon is the first hearing aid manufacturer to use pulliometry to measure how the innovative technologies in new Oticon Opn™ help to reduce cognitive load on the brain. This has especially been shown in a background noise where distracting conversation by several speakers is present. Oticon researchers looked carefully into the eyes of Opn™ wearers.  What they saw - 20% less listening effort* when trying to understand speech while others are speaking – makes Oticon Opn™ the first hearing aid proven to make it easier for the brain.
They may not have found the signs of love that the romantics did, but researchers did see less effort for hard of hearing people in listening situations very similar to those found when enjoying dinner with loved ones!

*compared to Oticon’s until then most advanced hearing aid Alta2 Pro