‘Better to hear you my dear’

US scientists have unveiled what they say could be the next generation of implants designed to offer hearing to the profoundly deaf. The new device described by the University of Michigan team fits directly to the auditory nerve.

The researchers claim it works better than cochlear implants, currently the leading technology. But the device has been tested only in animals, the Journal of the Association for Research in Otolaryngology reports.

'Exciting possibilities'

A UK researcher hailed the project as "potentially a brilliant idea". Cochlear implants have been in use since the mid-1980s, and are placed near to the nerve that carries sound impulses to the brain. However, they are still separated from the nerve by a bony wall and fluid, and users often find it hard to hear low-pitched sounds, which can make conversation difficult, especially in noisy environments.

The Michigan team has managed to place their tiny device inside the nerve itself in cats. Lead researcher Professor John Middlebrooks said testing showed the new device performed better over a wider range of frequencies, suggesting that users might be able to enjoy a far wider range of hearing.

They measured the cats' brain responses to sounds, and compared the results with those in cats given cochlear implants.

Professor Middlebrooks said: "The intimate contact of the array with the nerve fibres achieves more precise activation of fibres signalling specific frequencies, reduced electrical current requirements and dramatically reduced interference among electrodes when they are stimulated simultaneously."

He said his team would monitor how the auditory nerve coped with the implant over the next two years.

"If our work continues to go very well, we might begin human trials in no less than five years," he said. Dr Carl Verschuur, a lecturer in audiology at the University of Southampton's Institute of Sound and Vibration, said: "Potentially it's a brilliant idea.

"Although there could be some challenging technical issues with attaching the device to the nerve and keeping it there, it offers a solution to a lot of the problems with cochlear implants.

"There is a lot of distance between the cochlear implants and the nerve, so it is perfectly logical to do this. The fact they've managed to do this successfully in animals makes this an exciting study."

Brian James, from RNID, said: "Cochlear implants themselves have provided a revolution, and these implants - if successfully transferred to people - could offer further, major benefits."