There are some types of deafness which cannot be enhanced by wearing a normal hearing aid, that is a hearing aid which receives the sound via a microphone, amplifies it and then replays it into your ear. Luckily some of the people who suffer from these problems can be assisted in other ways.

One of these other methods is a cochlear implant. A cochlear implant device has to be surgically implanted into the ear. Cochlear implants do not amplify the sounds entering the ear, but instead they stimulate the functioning auditory nerves inside the cochlear. This is achieved by means of minute electrical impulses.

These cochlear units are very complicated and consist of quite a few tiny parts including a speech processor and a radio transmitter. As you can can imagine, this is rather an expensive operation and is still nor carried out routinely, not least because there are other options that can tried first.

The up-side is that most people who have had the operation have said that it was worth the money and that the results were fantastic. In fact, most patients said that their hearing was nearly as good as normal.

There is a vast improvement in hearing immediately after the operation, but hearing continues to get better for six months or more afterwards by means of tuning sessions and the body's natural adaptation. The results are a lot slower for children as it takes them longer to become accustomed to the electrical stimuli.

Various kinds of background noise can be a problem, but some of these issues can be tuned out, which is one of the reasons why it normally takes more than six months to get the unit attuned to you and your way of life.

For this reason the degree of success from having a cochlear implant depends largely on the patient. Some of the considerations playing an important part in the success of the implant are: how long, you have been deaf; how long you heard sounds before you became deaf; how well your brain remembers those sounds and the state of the cochlear and its auditory nerves

As mentioned above, the operation and tuning of a cochlear implant is costly. Of course, the final price tag depends on which doctor fitted the device and where he or she is located, but you could say that it will cost at least $50,000 and maybe twice that much. Fortunately, most health insurance schemes will pick up some of the costs, but the percentage they will pay varies a great deal.

The cochlear implant is the only device on offer at the moment to help sufferers with some types of permanent hearing disability - especially total deafness.

Until 2000, children could only have this operation if they were above the age of two years in the United States, but this age limit was then lowered to one year. Nearly two- thirds of those who have undergone a cochlear implant have been children and the majority of the children were between two and six years of age.