Getting sound results

From: Washington Times - Washington,DC,USA - Apr 24, 2007

By Christian Toto
THE WASHINGTON TIMES
April 24, 2007

Five years ago, Christopher T. Sutton wasn't a suitable candidate for a cochlear implant, a device that simulates sound for people who are deaf or suffer from severe hearing loss.

In November, Mr. Sutton received a cochlear implant.

"A majority of people who don't think they're candidates are now," says Mr. Sutton, education and marketing coordinator with the Bethesda-based Hearing Loss Association of America.

He can speak on the telephone and understand what the caller is telling him better than he once could.

"I'm starting to hear sounds I never heard before," Mr. Sutton says, adding that he once communicated chiefly through digital means such as e-mail.

The first wave of cochlear implants enabled deaf people to hear a facsimile of the world around them, but technological advances over the past five years have made the devices easier to use and far better at reproducing sound.

A cochlear implant has two distinct parts. One is inserted surgically in cochlea, the inner-ear organ responsible for hearing. An outer piece, which collects outside sounds and transmits them to the inner piece, connects to the recipient's head via a magnet behind the ear.

The devices work by directly stimulating the auditory nerve, unlike hearing aids, which simply amplify sounds.

About 22,000 adults and nearly 15,000 children in the United States have implants, according to 2005 data compiled by the Food and Drug Administration.

Not everyone responds favorably to the implants. Some grow frustrated with the device, while others fail to properly train themselves how to use them.

Saul Strieb, an audiologist with the Washington Hospital Center's Hearing and Speech Center in Northwest, says he sees more cochlear patients in his office than in the past and more surgeons are interested in the technology.

One clear improvement regarding the devices is that many implants are waterproof.

"That's a big benefit, especially for children," Mr. Strieb says. "Water doesn't damage the processors like they would in the past."

The latest implants also enable users to change their settings depending on the social situation. If an implant recipient is talking one on one with a pal, the device could be tweaked to maximize hearing levels. If he or she is in a room with lots of extraneous noise, the implant can be adjusted accordingly.

"The sound people perceive from it is individual. It depends on what processing setting they use," Mr. Strieb says.

Kim Jackson, vice president of clinical and sales for North America with Med-El Corp., one of several cochlear-implant manufacturers, says enhancements to the cochlear implant are making its benefits available to more people.

Today, the hard of hearing can opt for a cochlear implant instead of a hearing aid, while profoundly deaf people might get two implants, not just one.

"We can appeal to a different patient population," Ms. Jackson says.

Traditional cochlear implant surgery destroys whatever residual hearing remains in a patient, but Ms. Jackson says researchers are working on ways to implant the devices without doing permanent damage.

One of the company's newest devices relies on electric-acoustic stimulation, or EAS. The system combines a hearing aid with a cochlear implant in the same ear. The hearing aid amplifies lower frequencies while the cochlear implant supplies the higher frequencies.

Ms. Jackson says her company's researchers are looking into improving the speed of how cochlear implants work.

People with healthy hearing process sound stimulation simultaneously, she says. By comparison, cochlear implants process sound sequentially. First, sounds are picked up by a microphone in the outer component of the implant device. Then the processor converts those sounds into a specialized code that eventually is sent to the internal implant. The implant, according to Ms. Jackson, interprets the code and sends electrical impulses to implanted electrodes.

In the past, when cochlear developers tried to stimulate the auditory nerve at the same time, the patient might receive noisy sound because of the channel interaction occurring.

Ms. Jackson says her company is trying to make such simultaneous sound processing possible for more realistic results.

Tony Arnold, vice president of marketing for the cochlear implant manufacturer Advanced Bionics in Valencia, Calif., compares the advances in cochlear technology to the rise of HD imagery in television.

The digital signals delivered to the brain via cochlear technology once worked at a rate of 5,000 to 7,000 pulses per second. The latest models send up to 80,000 pulses per second, Mr. Arnold says. That allows for better sound detail, he explains.

Frequency resolution is also on the rise, he says, using television images for clarification.

While older cochlear models could deliver between 16 and 22 "colors," the newest implants serve up 120 spectral bands of sound.

The latter is aimed at letting implant recipients hear music in a way that's much more like natural hearing, he says.

Mr. Arnold says future advances aim to reduce the size of the implants and improve the results from bilateral implantation.

Such implant cases used to be relatively rare, but today they are a "small but modest" part of the cochlear market and growing rapidly.

"Our eyes are meant to work as a pair," he says. "The brain expects the ears to work together, too."

One issue remains regarding cochlear implants, and it has nothing to do with technology.

Mr. Sutton is a Gallaudet University graduate and says some deaf people consider cochlear implants an affront to deaf culture.

"People are starting to accept it more gradually," he says. "There's still a small division that does not want to accept it. ... They say, 'It's ruining our culture. It's going to destroy deaf culture and [sign] language.'

"The deaf community has come a long way over the years and are learning to accept the technology more as they see how positively it has impacted those who have it," he says.

Gallaudet University, however, did not respond to numerous requests for comment in time for publication.

Mr. Sutton says he understands those who are hesitant and in opposition to the technology, but he gently disagrees about the technology's impact. Further, he says, with the decrease in diseases such as rubella, which can cause deafness, the number of people born deaf will continue to fall. That, in a way, is more of a threat to the culture than cochlear implants.

And even the best cochlear implants have a limit.

"I'm deaf until I put my batteries in," he says.

© 2007 The Washington Times, LLC.