Cochlear Implants

In this article we will explain what cochlear implants are, how they function, the benefit they can provide, how to go about getting them and future developments in the technology.

What Are They?

A cochlear implant is a small electronic instrument that enables both adults and children with significant hearing loss to pick up certain sounds. Although they can help the deaf to make out sounds like music, environmental noise and the human voice, they do not bring back normal hearing. There are two main parts to the implant. An external piece fits directly behind the ear and an internal piece is surgically implanted under the skin.

How Do They Work?

The most familiar electronic device available for the hard of hearing is the hearing aid. Whereas a hearing aid amplifies the sounds it picks up, cochlear implants operate on a completely different principle. They use the sound signals received to stimulate the auditory nerve itself. A microphone, which is placed behind the ear picks up external sounds and passes them along to a speech processor, which is also located behind the ear.

The processor translates the sounds which are then transmitted to the surgically implanted parts within the ear. This surgical process involves cutting a flap of skin behind the ear where a receiver/transmitter is placed and inserting a special electrode into the cochlea. The receiver then receives signals from the speech processor, converts the information into electronic impulses and transmits them to the electrodes placed in the inner ear.

These electrodes then provide the stimulus to the auditory nerve. Finally, the auditory nerve signals the brain in such a way that the signals are recognised as sound. However, users of cochlear implants must learn to interpret those sounds. Therapy typically follows cochlear implant surgery to help with the relearning process.

Who Can Use Them?

Not all people who are hearing impaired or suffering from hearing loss can benefit from cochlear implants. Those who for a variety of reasons have experienced deterioration of auditory nerve function would get no benefit from them. Remember, cochlear implants work by stimulating the auditory nerve itself.

Most experts agree that these implants are suitable for the severely hard of hearing – those who can detect sounds between 70 and 90 decibels – and for the profoundly deaf – those who can detect sounds of 90 decibels or above. Those who lost their hearing as adults can learn how to associate the brain signals they receive with sounds they recall from earlier in life. Young children generally need extensive therapy after implant surgery to achieve maximum benefit.

How to Get Them

There are Cochlear Implant Centres located around the country, many associated with the medical centres of large universities. The post operative phase of a cochlear implant can be much longer than other surgeries, requiring extensive therapy with speech pathologists, audiologists and so on. Some adults may be unwilling or unable to extend the effort required for success. Cochlear implants in children will require a great commitment of time and effort from parents and other family members. This is not a procedure to be taken lightly.

Future Developments

As with many electronic devices, the future improvements in implant technology involve increased miniaturisation. As parts become smaller, they can be made more powerful. For example, as the size of the electrodes implanted in the cochlear implant decreases, more can be used. Some predict that in the near future up to ten times more electrodes than we use today will be able to be implanted.