Cochlear implants: your bionic ears

If you are hearing-impaired and hearing aids are insufficient, you may want to consider cochlear implants.

• Unlike hearing aids, cochlear implants work not by amplifying sound but by directly stimulating the auditory nerve inside the inner ear through a surgically-implanted electronic device. They are often called "bionic ears" and the hearing they provide is not exactly normal, but more like the "sensation" of sound.
• Many people who use them, however, interpret sound well enough to converse on the phone.
• Provided the auditory nerve is still functioning, cochlear implants can make a huge difference to people with profound hearing impairment for whom hearing aid amplification is insufficient. They are increasingly being offered to adults as well as children.
• Implants can be life-changing. In adults, depending on the duration of deafness, they can help people return to work and a near-normal home life. Given early enough to children who are born deaf, they can enable them to develop good speech and language, and enjoy normal schooling.

• If you get little or no benefit from a hearing aid, you could consider an implant. The operation is carried out under general anaesthetic and usually involves two or three days in the hospital.
• The implant itself consists of electrodes inserted into the cochlea, which will be "switched on" at a later stage. In addition, a tiny receiver incorporating a magnet is inserted under the skin above and behind your ear — the magnet is to make sure that the external transmitter remains in place directly beside the implanted receiver.
• To use the implant, you need to wear a transmitter coil behind your ear along with a microphone and speech processor either behind the ear, like a hearing aid, or in a small box that can be clipped elsewhere, such as a waistband.
• The microphone picks up environmental sounds and converts them to electrical signals, which are sent via the processor to the transmitter. The electrodes in the implant detect these and stimulate the hair cells in the cochlea to send signals down the auditory nerve, as in natural hearing.
• When the device is switched on it can take a while for your brain to learn to interpret the signals as distinct sounds, but you will soon become aware of environmental noises, such as alarms and doorbells, and learn to distinguish between them.

• Although the quality of sound is not normal, implants bring your hearing sensitivity to normal levels.
• A great benefit is that you'll be able to tell immediately when someone is talking, which can help you to follow speech in conjunction with lip reading.
• It also enables you to "hear" how loudly you are speaking, which can be a great help in conversation. Some people get good enough sound quality to allow them to understand speech directly and have near-normal conversations as long as there's no background noise.