By Bae Ji-sook
Being able to hear is an intricate process. What we call sound is actually vibrations detected by the ear and transmitted to nerve impulses that are perceived by the brain in the temporal lobe.
There are about 214,420 people registered with the Ministry for Health, welfare and Family Affairs with hearing or speaking disorders mainly stemming from problems around the ear.
About half of the patients have genetic factors. They were audibly impaired from birth. Many of them have problems with the snail-shaped cochlear in the inner-ear part.
About 1.5 to two out of 1,000 are born with a certain level of aural malfunction. "Women with thyroid disorders or diabetes are most likely to give birth to these babies. It is recessive heredity," Professor Chang Sun-o of the Seoul National University Hospital said.
For those who have problems in the ears exterior or eardrums, most often the result from an inflammation of the middle ear, replacing the eardrum with an artificial one is an effective procedure. For those with cochlear problems, conventional hearing aids have been proven less effective and more inconvenient.
Cochlear implants, an electronic device providing a sense of sound to a person, have rapidly become a good alternative.
"Many hearing aids last for less than 10 years. They are expensive. I can safely say that the implant is by far the safest and most cost-effective way to improve auditory ability at the moment," Chang said. Since the health ministry decided to expand the National Health Insurance coverage in 2008, the patients pay less than 25 percent of the fee.
The device has two parts: a small box that is used outside the body and an implant. The pieces contain a microphone, speech processor, transmitter, receiver and stimulator to replace the function of the cochlear.
When a person catches a sound, the device delivers the information by electronically stimulating the auditory sense and eventually the brain. The surgeons implant the interior device in the cochlear area and the patients should carry the exterior box to control and "decode" the senses.
Chang said within two weeks people can "sense" sounds. "It is a big improvement. They are able to detect sounds in the early stages, but it takes time for them to realize it."
Chang said the procedure is not suitable for people who had their auditory senses "destroyed."
Also, whether to use the device on newborns is drawing ongoing debate. Chang backs the early-stage surgery. "I say when a baby is over six months old, we can perform it. It will be better for him or her to start hearing things and speaking like their peers during childhood," he said.
Currently, international scientists are studying ways to improve the artificial cochlear so that it can be recharged while sleeping on a pillow-shaped recharger.
"Of course, that will take quite a long time," he said.
The surgery after-care is also important. The patients who have received the procedure should get hearing training for about a year. In specifically sensitive cases, the period could be longer.
Chang said the government should look at supporting such rehabilitation programs. "If you cannot get proper guidance on using the device, implantation is of less use," Chang said.
At the moment, Chang and several other SNU researchers are working on developing domestic cochlear implants. "We have finished making the sample, but I guess it will take another two to three years for us to present a perfectly safe device to people," he said.
Tips for Keeping Your Ears Healthy
Chang said listening to music through earphones or headphones doesn't cause hearing disorders as many believe. "I think it has more to do with a sudden loud sound such as a machine breaking down or construction materials falling on the ground that can be much more dangerous," he said.
He said the biggest factor for those who have hearing disabilities after birth is the inflammation in the middle ear. In order to prevent the illness, Chang stresses hygiene. "Always try to keep the ear clean," he said.
These days, hospitals and clinics provide free audibility tests of fetuses for pregnant women so that parents can be prepared if the baby comes out with hearing difficulties.
Some antibiotics or cancer treatment drugs can harm the aural ability, he warned. "Always consult your doctor," he said.
|Who is Chang Sun-o?|
Chang graduated from Seoul National University. He said he has performed about 1,000 cochlea implants here.
Having served as a department chief at the Bohun Hospital when he was 37, he has held several prestigious positions.
Chang also served as head of the Korean Audiological Society and the Korean Otologic Society.
Chang is a passionate researcher, who says he loves gathering and analyzing data during his free time.