Bionic Ear creator wins eminent

Bionic Ear creator wins eminent medal
– and files more patents

Media briefing 11 am, Thursday 27 July 2006

An award and new patents mark the next steps for Australia’s Bionic Ear.

The patents focus around techniques to preserve, enhance and utilise any remaining auditory hair cells. They will contribute to a future bionic ear giving greater clarity, music appreciation, and help for people with partial hearing loss, according to the Bionic Ear’s inventor, Graeme Clark who will receive the Ian Wark Medal at a lecture and dinner to be held in his honour in Melbourne today.

“The creation of the Bionic Ear – over twenty years ago – was a scientific and commercial triumph,” says Professor Kurt Lambeck, President of the Australian Academy of Science.

“Today, seventy per cent of the world’s cochlear implants are made by one company, Cochlear Ltd, using Clark’s invention. But that’s not enough for Clark. He is helping the next generation of researchers to take the next step forward to a better bionic ear. And that’s illustrated by the latest patents filed by him and his team.”

“The medal recognises scientific contributions to the prosperity of Australia – Graeme Clark was an obvious choice,” says Lambeck.

Two patents have been filed which Clark hopes will lead to the cochlear implant of the future. The patents should not only allow profoundly deaf people to hear with greater clarity than ever before, but even to appreciate music, Clark says.

“Gone will be the days when a cochlear implant involved destruction of any residual hearing.”

The two patents derive from recent work at The Bionic Ear Institute in collaboration with Melbourne, and Monash Universities and St Vincent’s Hospital, Melbourne.

The patents focus around techniques to preserve, enhance and utilise any of the auditory hair cells retained by people requiring bionic ears. The patents suggest ways in which these remaining fragile hair cells can be:

stimulated to enhance quality of hearing – by mechanical and electrical stimulation
protected during bionic ear implantation - by driving a steerable electrode into the inner ear

The patents may also lead to spin-offs in other areas of nerve regeneration.

The Ian Wark Medal and Lecture honours the contributions to Australian science and industry by the late Sir Ian Wark, CMG, CBE, FAA, FTSE. The award recognises contributions to the prosperity of Australia where such prosperity is attained through the advancement of scientific knowledge or its application, or both.

For more information on the Wark medal visit Australian Academy of Science website www.science.org.au/awards/wark.htm

More about the latest work

The hair cells of the inner ear act in the same way a pick-up in an old record player or crystal radio. As the fine hairs move back and forth in response to the vibrations of sound, their compression and expansion generates an electric charge in the body of the hair cell. Damage to or loss of the delicate hair cells is a significant cause of deafness. A cochlear implant is essentially an electronic substitute. Like a tiny microphone it picks up sound waves and turns them into electrical impulses which are used to stimulate the auditory nerve cells directly.

The patent lodged this week by the University of Melbourne is the one likely to be developed the soonest. It is for a two-part device which firstly uses electrical signal to mechanically excite residual hair cells, and secondly pairs it with electrical stimulation of nerves directly as in a normal cochlear implant. For lower frequency sounds one part of the device would vibrate the basilar membrane from which the remaining hair cells grow, thus stimulating them in a normal fashion. At higher frequencies the device would rely on directing electrical impulses into the nerve.

“The idea is to coordinate the two forms of stimulation under the control of one system,” Prof Clark says. “It should improve the clarity of hearing in a noisy environment, and could even lead to musical appreciation.” With the right industrial partner, Prof Clark believes such a product could be ready within a couple of years.

In the medium term, four or five years down the road, Prof Clark believes we will see bionic devices which are easier to implant, and are able to be steered into position. These implants will make use of the properties of shape memory alloys, and they are the subject of the second patent, lodged in association with Monash University on the back of research funded by the Institute of Engineers, Australia.

Alloys of nickel and titanium, such as nitinol, can initially be moulded into a particular shape. They can then be mechanically bent into another form. But, with the passage of a small electric current, they will move back into the original shape. In the case of the “steerable” electrode, the idea would be to mould a bionic ear electrode bundle into a shape that would closely conform to the exact part of the inner ear where it should sit. The device could then be bent into a form that is easy to insert and implant. Only when it reaches its final site would it be snapped back to its original shape and fitted.

Monash engineers have been developing three-dimensional models of the inner ear, to allow the shape and trajectory of such a device to be calculated, as well as the stresses and forces on the delicate inner ear structures. In practice, surgeons would customise the model for individual patients using magnetic resonance imaging (MRI) scans. During implantation insertion of the bionic device could be under computer control, and there may even be inbuilt sensors providing feedback on positioning.

Both patents fit together—making use of existing hair cells, better control of implantation to avoid damaging hair cells, and better contact with electrodes. “In five years we should have a much better product,” Clark says.