Bees as inspiration for better hearing implants

A familiar scenario: you’re at a party and everyone is talking at the same time. It takes effort to filter out the voice of the person you’re talking to. It’s quite the feat for people with perfect hearing, so imagine what it’s like for people who are hearing-impaired. This cocktail party effect is a problem that current hearing aids and implants cannot solve yet. Neuroscientist Martijn Agterberg wants to change this and is largely inspired by bees. He is competing in the NWO Venture Challenge with his start-up BeephoniX

Sound localisation

People with fully-functioning hearing are able to precisely estimate where a sound is coming from, even with their eyes closed. Sound coming from the right enters the right ear first, and the left ear later. The difference in time is registered by our brain, which allows us to determine where the sound is coming from. This is very difficult for people who use hearing aids or implants, because the current systems are not able to localise sound. This makes it difficult for people with a hearing aid to engage in conversations in a busy environment: they aren’t able to hear where each sound is coming from.


On a team day, neuroscientist Martijn Agterberg attended a presentation of beekeeper Marius Woensdrecht where he realised that bees are probably able to locate sound. Agterberg: “Marius talked about bees being able to hear. I asked where the ears are located. They turned out to be located on antennas that the bees can move. I thought: ‘That has a reason, maybe it’s a mechanism to locate sound’.”

The distance between bees’ ears is so small that they cannot deduce where the sound is coming from using a difference in time. And bees don’t have the nicely shaped auricle that humans have, which helps us analyse whether sound is coming from above or below. Apparently, bees locate sounds in a different way than humans. Agterberg theorised that bees are able to move their ears to determine where sounds are coming from. In 2020, Agterberg was given the chance to study this with a NWO Open Mind grant.

“I promptly found an article by Harvard researchers written in 2019. The article itself is about the Drosophila, a fruit fly. By moving its ears, the Drosophila generates its own Doppler-effect. They are able to scan for this and determine where the sound is coming from. Brilliant but very simple at the same time.”

Hearing implants: 5 to 10 times better

The idea for applying this to a better hearing implant can quickly: if the directional sensitivity of the implants can be improved, the quality of hearing can be improved for hearing-impaired people. Agterberg: “By using a directivity sensor in the microphone in implants, you could potentially be able to better determine where the sound is coming from with one implant only, and process the sound much more efficiently in the sound processor. This allows people to keep up with conversations in surroundings with a lot of background noise. With an improved sound processor, you’re able to better understand speech in complex listening situations than when you’re listening with two implants.” Agterberg built a prototype with a NWO Take-off grant and it worked: the prototype has a so-called ‘beam shaper’ that’s 5 to 10 times better, making the prototype 5 to 10 times better than the current hearing implants.

Prof. Mylanus van de afdeling KNO van het RadboudUMC en Dr. Martijn Agterberg
Prof. Mylanus van de afdeling KNO van het RadboudUMC en Dr. Martijn Agterberg

Agterberg built a prototype with a NWO Take-off grant and it worked: the prototype has a so-called ‘beam shaper’ that’s 5 to 10 times better, making the prototype 5 to 10 times better than the current hearing implants.

Agterberg: “There is an enormous market for hearing aids, it is expected that one out of four people will suffer from hearing loss in 2030, partly due to the increase of the number of old people. Globally, this will result in a turnover of €18 trillion with regards to the purchase of hearing aids/implants. In principle, we’ll focus on the middle ear implants. That’s quite a niche. If our product does well on that market, we can expand to cochlear implants and hearing aids. And we also see opportunities for our product outside of the hearing industry, for example at the Ministry of Defence, for applications in for example leak detection in high risk industries, in the music industry, but also safety earphones.” More than enough reasons to take the step to the market.

Venture Challenge

Colleagues of Mercator Launch pointed out the Venture Challenge to Agterberg. In that challenge, beginning academic entrepreneurs will get ten weeks of professional support in drawing up a solid business case to bring their scientific invention to the market. At the end of the programme, the participants pitch their plans to a panel of experienced entrepreneurs and investors, who also choose a winner of the €25,000 voucher.

“By now I have a patent and a prototype that is working very well, due to the Mercator Launch and a very involved team consisting of Klaas-Jan Kakebeeke, Patrick Wijnings and Marc van Dorth. We hope to make BeephoniX an Ltd in December. “We have a very solid business plan because of the Venture Challenge.”

More than enough ambition

There is more than enough ambition left for the future, both with regards to the research and perfecting the prototype. “The first step to take is making the prototype smaller. Right now, the prototype is 12 centimetres. We hope to reduce this to 2 centimetres by 2025, so it can be built into the processor of a hearing implant.

I also want to study how bees move their ears. Is that movement asymmetrical? Is sound localisation possible because of the processing of multisensory information? Right now, we use one moving microphone in our prototype. But what happens if we use two microphones, and what if they move asymmetrically, like bees’ antennas? We might be able to improve hearing aids and implants even more!” By now, this research has started. Two students are working on the research under the supervision of Martin Lankheet (WUR) and Richard van Wezel. The bees that are used for this research are provided by the Bee House in Wageningen.

The pitches for the NWO Venture Challenge autumn 2022 took place on 17 November 2022.