THEME – COMPETITORS COLLABORATE

A human touch to hearing aids

Three Danish companies jointly control almost half of the world market for hearing aids. Together they are financing an independent centre which conducts research into how we humans perceive sound.

By Morten Andersen

Professor Torsten Dau heads the Centre for Applied Hearing Research at the Technical University of Denmark (DTU). The centre is financed by the industry, DTU and the Danish state. The three main Danish hearing aid companies equally share the industry’s part of the bill.
Photo: Peter Clausen.

Three of the six companies that dominate the world market for hearing aids are Danish. Oticon, Widex and GN Resound jointly account for about 45 per cent of global sales.

“It is amazing that a small country can have such a significant impact on an industry,” says Professor Torsten Dau, who heads the Centre for Applied Hearing Research at the Technical University of Denmark (DTU).

“There are several explanations, but one of them is that the three Danish companies have been careful not to focus solely on the technical aspects All three are very interested in the softer side of the profession, which is about the human perception of sound.”

Torsten Dau is German. In 2003 he left his position at the University of Oldenburg to become professorial head of the then newly established Danish centre, which is financed by the industry, DTU and the state. Oticon, Widex and GN Resound equally share the industry’s part of the bill.

“It is outstanding that three companies, who are competitors on a day-to-day basis, have been able to agree on financing a centre like ours. That was certainly one of the main reasons why I could not say no to the position,” says Torsten Dau.

Pressurised to collaborate
There is also a lot of activity in this area in Torsten Dau’s homeland, Germany:

“But there is not anything like as close a contact with the industry as here. It is an amazingly favourable situation that you have three major companies in such a small area – and then they are even able to collaborate. Denmark also has a broader network of companies and institutions that are interested in acoustic technology. Companies such as Brüel & Kjær (sound measuring instruments etc.) and Bang & Olufsen are also contributing.”

Vice-president and research director Søren Westermann of Widex confirms that there is a good atmosphere between the three Danish manufacturers of hearing aids:

“It all started when the Danish hearing health service almost commanded us to collaborate, so that hearing centres had a better knowledge of the market when they were purchasing. But we quickly discovered that we had much joy of each other.”

Initially the three companies supported a major research project at DTU on how to improve the ability of hearing aids to help the hearing-impaired in noisy surroundings. Later the companies made a common programming platform, which hearing aid retailers use. The platform enables the user’s data and results from an audiological test to be read-in directly, after which the retailer can choose the best product, independently of the manufacturer. Today all retailers have the platform, just as all manufacturers worldwide have joined the system. Furthermore, the entire industry has shared patent monitoring – also a Danish initiative.

“So we three Danish companies have really shown that we are able to achieve results together, although we are competitors,” Søren Westermann concludes.

The user’s opinion is important
For many years the most important task for the companies was to make the hearing aids as small as possible. Today hearing aids are so small that they can sit right inside the ear canal. So now there is no point in making the hearing aids smaller. If you did that, you would have to put filling material into it, so that the hearing aid could fill out the ear canal. The focus has instead moved to how hearing aids can be made even better.

“In this area the Danish companies have a really strong position, because they have always been strongly oriented towards basic research. Of course, foreign companies are also conducting research, but they have traditionally focused on areas close to actual use,” says Professor Torsten Dau and elaborates:

“In addition to supporting the centre at DTU, the Danish companies each have their own audiological research departments where they make systematic efforts to map how users regard the new hearing aids. One thing is the measurable acoustic properties. Another is how people assess the quality.”

Attracting students from abroad
One should not think that the Centre for Applied Hearing Research directly contributes to the development of hearing aids, emphasises Torsten Dau:

“We would like to, but all the three Danish companies have development departments that carry out the task a lot better.”

So the distribution of roles is such that when some of the centre’s results can be used in new hearing aids, the three companies each hurry back to get them incorporated in a new product before their competitors. And competitors are not only to be understood as Danish ones.

“We are an independent research centre, so our results are published in the public domain. And we are also collaborating with companies outside Denmark,” says Torsten Dau.

“We are actually very internationally oriented. 60 per cent of our students are from abroad, and out of our current 11 PhD students, only three are Danish. It reflects how the Danish environment in audiological research and development is regarded as attractive internationally.”

It began in the 1950s

At the beginning of the 1950s, Denmark adopted two laws which would turn out to be of major significance for the development of hearing aids.

The first law, which was passed in 1950, established a Hard of Hearing Committee and hearing centres, where the deaf and hard of hearing could apply for help. The Hard of Hearing Committee consisted of just five members, of whom two were appointed by the Danish Association of the Hard of Hearing – they were in other words representatives of the users.

In 1951, another law introduced an insurance scheme, which made it cost-free to get a hearing aid.

At that time, there were three hearing aid manufacturers in Denmark. Oticon produced the first Danish hearing aid back in 1946.

The Hard of Hearing Committee and the hearing centres chose to maintain competition between the three manufacturers and so encourage them to produce increasingly good hearing aids.

Two of the companies, Oticon and Widex, still exist, while the third company, which was founded by factory owner Gerd Rosenstand and produced under the name of Danavox, was sold in 1977 to Store Nordiske Telegrafselskab (Great Nordic – or GN), and the company’s name today is GN Resound.

The cocktail party problem
An example of the form of sound perception that the three Danish companies and the centre at DTU are interested in, is colloquially called “the cocktail party problem”, where a hearing-impaired person is talking to another person in a room in which there are many different conversations going on and perhaps also other forms of sound. How does the hearing aid know which of the many competing sounds to focus on? The problem does not get any easier when the other person in the conversation occasionally stops speaking so that the sound being focused on disappears completely.

“It is a very tricky problem. You can take a large group of people who all have the same degree of hearing loss, and see that half of them have major difficulty, while the other half do not. We would very much like to explain what the difference is between the two groups. That would be the first step towards solving the problem,” says Professor Torsten Dau of DTU.

In contrast to most other sounds, human speech varies a lot both in frequency and amplitude. The research centre has developed a computer model of a virtual test person to model how this type of sound is perceived in rooms with different acoustic characteristics. A related project examines the connection between impaired hearing, problems of understanding speech against background noise, and the ability to determine the direction of sound as well as resolving it in relation to time and frequency.

The common foundation of the projects is that the inner ear is able to make an initial frequency analysis of the signal it receives, i.e. the signal is split into various parts, depending on the frequency. This division is maintained in the further processing: certain nerve cells in the brain are dedicated to handling the various frequencies. In addition, there are several other principles for processing the sound signal on its path into the brain – for example neurons that code various angles of sound reception by combining input from both ears. Other cells mainly react to particular energy fluctuation patterns, which are typical for speech signals. Lastly, the information is gathered according to the principles of radar technology, and a mechanism in the brain determines whether a certain sound is audible or has been masked by sources of noise.

The final objective is to develop software that can be put into a hearing aid so that the cocktail party problem is solved for people with certain forms of hearing loss.

Minimal – also in power consumption

Despite the fact that a modern hearing aid can contain more than 10 million transistors, its power consumption is only 0.5 milliwatt. In equivalent terms, a single TV set on standby uses as much power as 40,000 hearing aids.

Illustration Lars Chrois