New Hope for People Who Have Hearing Problems

Symphony No. 9 music by Ludwig van Beethoven was clearly audible. Although not clear as the original voice, recorded music through a new microphone that plugs into the middle ear of human corpse that had the sound of the whole show.

Microphones planted in the cochlea in the ear hearing-impaired patients is not new. Cochlear implants have restored hearing approximately 220 thousand deaf people.

Darrin Young, an electrical engineer at
the University of Utah, has developed a tiny
prototype microphone that would be
implanted in the middle ear. (Picture from:  
http://www.eurekalert.org/)

But the microphone and radio transmitter that hearing aids are still outside the body, ears stuck out. Not only creating a social stigma for users, reliability of the instrument is also a problem because it hinders the patient to swim.

Now an engineers team of University of Utah, the United States, successfully developed a prototype of a small microphone that can be implanted in the middle ear. Thanks to this innovation, no one will know if the patient is hearing-impaired using hearing aids. Patients also can swim without worrying about broken microphone.

Cochlear implant recently successfully tested on four bodies of human ear canal. The results of this study was published in the journal Transactions on Biomedical Engineering, published the Institute of Electrical and Electronics Engineers,

The prototype implants, measuring 2.5 x 6.2 millimeters and weighs 25 milligrams. The prototype, which is only about the size of the rubber-eraser on a pencil might still be improved in some parts. Size, for example, still have to be reduced again. Young wants the microphone was cut to only about 2 x 2 millimeters.

Similarly, the ability to detect sounds softer and lower pitched must also be increased. "So the test on a human life may still have to wait three more years," said the study's lead author, Darrin J. Young, a professor of Electrical and Computer Engineering at the University of Utah and the Utah Science Technology and Research Initiative.

The microphone includes an accelerometer and silicon chip that detect vibrations and convert them to electronic signals sent to electrodes in the inner ear's cochlea. (Picture from: http://news.cnet.com/)

Research shows that the incoming sound can be transmitted most efficiently to the microphone when the incus, one of the three hearing bones in the middle ear, removed by surgery. To plant an implant that requires such an operation, researchers must first bagged the approval from the U.S. Food and Drug Administration.

Cochlear implant prototype was created by Young with Mark Zurcher and Wen Ko, a former colleague in the Department of Electrical Engineering at Case Western Reserve University in Cleveland. Young also involve the ENT doctors, Maroun Semaan and Cliff Megerian from University Hospitals Case Medical Center.

Although yet to be repaired and will be tested on patients next three years, this tool will transform the lives of hearing-impaired in the world. Based on data from the U.S. National Institutes of Health, nearly 220 thousand people with severe hearing loss and deafness around the world have received cochlear implants. One third of them live in America and two-fifths of the recipient's device is the children.

In the conventional cochlear implants, there are three main parts are worn externally behind the ear, the microphone for capturing sound, word processors, and radio transmitter coil

Internal ear implant. (Picture from: 
 KORAN TEMPO 3887)

Under the skin behind the ear radio receiver and stimulator implanted to convert voice signals into electrical impulses, are transmitted via cable to between four and 16 electrodes that penetrate to the cochlea in the inner ear and stimulates the auditory nerve so that the patient can hear.

"Unfortunately when it was still connected to something outside the head," said Young. "Imagine a child who wore a microphone behind the ear. That causes problems in a variety of activities. Swimming is a major problem. He was also uncomfortable wearing the implant if you have to wear a helmet."

For adults, the use of hearing aids no longer issue an inconvenience, but the social perception of them. "Wearing of this tool shows that you are disabled and that is the reason why many people do not want to wear it," says Young, "they are concerned about the negative image."

In addition to the negative image of the conventional use of cochlear implants, patients have the risk of equipment damage. "If there is a cable from the microphone connected to the coil, the cable may be broken," he said.

One day, Young said, a microphone is likely to replace conventional hearing aids, especially for patients whose bone degraded his hearing and could not accept either of the sound with conventional hearing aids. *** [UNIVERSITY OF UTAH | TJANDRA DEWI | KORAN TEMPO 3887]

Differences in Cochlear Implants and Inner Ear Microphone

The voice usually moves into the ear canal and makes the eardrum vibrate. On what is known as the umbo, the eardrum is connected in a series of three tiny bones, the malleus, incus, and stapes or the hammer, anvil, and stirrup.

The bones were vibrating. Stapes or stirrup touches the cochlea, the inner chamber in fluid-filled ears. On the membrane of hair cells in the cochlea moves that trigger the release of neuro-transmitter chemicals that carry voice signals to the brain.

At the hearing-impaired person who becomes a candidate of cochlear implants, hair cells do not work for various reasons, ranging birth defects, drug side effects, excessive exposure to loud noise, to a certain virus infections.

In the cochlear implant, a microphone, signal processor and transmitter coil used outside of the head sends the internal receiver stimulator, which is embedded in the bone beneath the skin. This sends a signal to the stimulator electrodes are implanted in the cochlea to stimulate the auditory nerve. At this hearing aid, ear canal, eardrum and hearing bones jump.

In contrast to the implants, all external components into the body planted by Young. Sound moves through the ear canal to the eardrum, which vibrates like a normal ear. However, the umbo placed a sensor called an accelerometer to detect vibrations.

This implant devices still require batteries recharge. Patients can use the charger to recharge when sleeping at night. "These batteries can supply enough power for the implant to operate between one to several days," said Young. *** [UNIVERSITY OF UTAH | KORAN TEMPO 3887]
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