Frequently Asked Questions
Adapted from the British Cochlear Implant Group (BCIG)
What Is A Cochlear Implant?
A Cochlear Implant is a device designed to help severe to profoundly deaf individuals who gain little or no benefit from hearing aids. With their cochlear implant they gain awareness of environmental sounds, most can understand speech without lip-reading and some can use the telephone. The cochlear implant system converts acoustic sound waves into weak electric currents, which are delivered to the immediate vicinity of the auditory nerve in the inner ear or cochlea. The auditory nerve is stimulated by these electric currents and transmits nerve impulses to the brain, where they are understood as acoustic sensations.
According To My Doctor, I Suffer From Nerve Deafness. Does This Mean That The Hearing Or Auditory Nerve Is Destroyed?
No, the auditory nerve may still potentially function even in cases of nerve deafness; in most cases the auditory nerve is intact (or partially functional), but the hair cells in the cochlea are damaged or destroyed. Normally, when sound waves reach the ear they are converted into electric currents by tiny sensory hair cells. The auditory nerve responds to the electric current and passes it on to the brain. We experience this as “hearing”. If the hair cells are damaged, there is no mechanism to convert the sound waves into electric currents, and without electric current the nerve is not stimulated. As a result nothing can be heard.
In Other Words, Damage Or Destruction Of The Hair Cells In The Cochlear Can Result In Total Deafness, But The Auditory Nerve Can Still Be Fully Intact?
In principal, yes! In most cases, however, part of the nerve is in fact damaged.
How Can The Cochlear Implant Help?
The cochlear implant conveys weak electric stimuli to the vicinity of the auditory nerve. The electric stimulus activates the nerve, which then transmits a signal to the brain. The brain recognizes this signal and we experience this as “hearing”. The cochlear implant has the same function as the hair cells, in that it transforms sound into an electric current that stimulates the auditory nerve. Nevertheless, the result is not the same as normal hearing.
What Does The Internal Component Consist Of?
The inner component or implant package contains an induction coil and an electrode array. With surgery this implant package is implanted in the Temporal bone behind the ear. The electrode array is introduced into the inner ear (cochlea). An electric current across the electrode array activates the auditory nerve and the result is that you “hear”.
What Is The Purpose Of The External Component Of The Cochlear Implant?
The external part converts sound waves into electric signals. It consists of a microphone, a small speech processor and an external coil (see diagram of cochlear implant system). The microphone picks up the sound waves and transforms them into weak electric signals. The speech processor modifies these electric signals. They are then sent to the external coil via a cable. If the external coil is placed over the internal coil, signals will be transmitted through the intact skin to the implant and electrode array. In this way the auditory nerve is stimulated, which results in acoustic sensations.
How Large Is The Speech Processor?
The size of a high powered Hearing Aid
Where Is The External Coil Situated?
The external coil must be placed on the skin exactly over the internal coil in the implant package. If the two coils are not correctly aligned, the sound impressions will become quieter or vanish entirely. Correct positioning of the external coil is therefore essential.
How Can The External Coil Be Correctly Positioned?
The external coil contains a magnet that is attracted by a second magnet inside the implant package, which places it into the proper position on the skin.
Can The Speech Processor Be Removed At Night?
Yes, the speech processor can be removed at night. However, it should then be switched off, so as not to exhaust the battery. The speech processor may be worn through the night if desired – some users like to ‘keep in touch’ with the hearing world even when asleep.
Will An Implant Be A Hindrance In Activities Like Football, Swimming And Tennis, For Example?
Generally the implant itself is in no way restrictive. For some sports, such as swimming, the external part is removed beforehand, just as one would remove a hearing aid.. Some active sports or pastimes can be dangerous to the implant or external parts however, so please ask your clinic for advice on activities where there is the possibility of blows to the head.
Is It Possible That The Speech Processor May Need Repairing?
As in any electronic device, sometimes faults do occur. The manufacturer or CI clinic staff can repair the speech processor. Do not attempt to make repairs yourself.
Where Are These Repairs Carried Out?
Some minor repairs can be carried out at the hospital or clinic where the processor was obtained. For all major repairs the device must be returned to the manufacturer.
Is Hearing Absolutely Normal With A Cochlear Implant?
No. From individuals who could hear before they were deafened we know that the acoustic impressions from a cochlear implant differ from “normal hearing”. Users initially describe the sound characteristics with words like “mechanical”, “technical”, and “synthetic”. This perception changes over time, most users do not notice this artificial sound quality after a few weeks.
Does The User Have To Pay For The Repairs?
Children are not required to pay for repairs or upkeep of their speech processor until the age of 18 years. After 18 years all recipients must pay their own battery, spare parts, and repair costs. All recipients (children as well as adults) must have their speech processors insured against loss, theft, and non-accidental damage.
How Long Does It Take Before The User Derives The Maximum Benefit From A Cochlear Implant?
From research we know that the performance of individuals can be quite different. However, benefit starts immediately and for adults reaches a plateau at about 3 months after the initial tuning sessions. Although performance continues to improve, after this time the improvements are at a slower rate. It is fair to say that for many users performance continues to improve for several years. In children improvement may be at a slower pace. A lot of training is needed after implantation to help the child use the new ‘hearing’ he/she now has.
What Acoustic Signals Can Be Perceived With A Cochlear Implant?
With a cochlear implant most acoustic signals of medium and high intensity can be perceived as well as quieter sounds. Patients report that they can perceive footsteps, slamming of doors, sounds of engines, ringing of the telephone, barking of dogs, whistling of the kettle, rustling of leaves, the sound of a light switch being switched on and off, and so on.
Are Users Able To Understand What Is Being Said Without Looking At The Speaker?
A large number of users are able to understand speech without lip-reading. However, even in cases where this is not possible, there is some improvement in lip-reading with the implant.
Does The Cochlear Implant Facilitate Lip-Reading?
Yes, users are able to perceive characteristic sound patterns of speech. The addition of these impressions to the observation of movements of the mouth and face facilitates lip-reading. The degree of help for lip-reading depends on the patient’s practice in dealing with acoustic signals and speech.
I Am Told Sometimes That My Voice Is Either Too Loud Or Too Quiet In Certain Situations. Does The Cochlear Implant Help In Controlling The Loudness Of One’s Own Voice?
Yes. The cochlear implant enables the user to control the volume of his voice in two different ways.
Since the user can now perceive his own voice, he is able to tell if he is speaking loudly or quietly.The cochlear implant allows background noise to be “heard”. Most patients learn to adjust the volume of their voice to the volume of the background noise.
Are Users Able To Make A Telephone Call?
Many users are able to make telephone calls and understand familiar voices over the telephone. Some good performers are able to make normal telephone calls and even understand an unfamiliar speaker. However, not all users are able to use the phone.
Does The Cochlear Implant Help In Watching TV Or In Listening To The Radio?
For many users the cochlear implant does make watching TV easier – especially when you can also see the speaker’s face. The radio is more difficult as there are no visual cues available.
Can A User Listen To Music?
Some users are able to enjoy music. Some enjoy the sound of certain instruments (piano or guitar, for example) and certain voices. For others, the information transmitted by the implant may be insufficient to allow them to fully enjoy music.
Are There Any Unpleasant Sounds?
During the speech processor tuning the clinician will perform certain tests to find out when a patient experiences acoustic signals as being unpleasantly LOUD. The speech processor is then adjusted so that no acoustic signal reaches this point. There may be other sounds that are not found to be ‘pleasant’ due to their nature (e.g. baby crying) but these should not be uncomfortably loud.
Does The Cochlear Implant Influence Tinnitus?
Many users find that tinnitus decreases while their device is operating. Usually tinnitus decreases only on the implanted side, and for many users it remains reduced even when the speech processor is not switched on. Most users experience a lessening of tinnitus, in some cases it remains unchanged and there have been reports of rare cases where it is worse.
What Basic Risks Are Involved In Cochlear Implantation?
Apart from the risk due to anesthesia (as in every operation) the risks are the same as those connected with a middle ear operation as performed daily in an Ear, Nose and Throat clinic. Theoretically, the facial nerve might be damaged; given normal anatomical conditions, however, and with an experienced surgeon, this is highly improbable. Other conceivable risks are an intensification of tinnitus, disturbance of taste, and an enhanced feeling of dizziness.
Since When Have Cochlear Implants Been In Use?
The first experiment with electrical stimulation was undertaken in France in 1950. From the late 1970’s there have been an increasing number of cochlear implantation’s each year. The first truly commercial devices were available from the early 1980’s.
Do Those Who Have An Implant System Use It?
The great majority of Implantees use their processor regularly from morning to night.
What Can Children receiving a Cochlear Implant be expected to Achieve?
Since children are better able to utilize new information than adults, they can also be expected to benefit more from a cochlear implant. Very limited hearing can have a considerable influence on a child’s ability to learn to talk and on overall development. The speech of most children with cochlear implants is of better quality and more intelligible than their peers using acoustic hearing aids.
Are There Different Types Of Cochlear Implant?
Different implant programmes may work with different Cochlear Implant manufacturers. The Southern Cochlear Implant Programme works with 2 manufacturers, MED-EL (an Austrian company) and Cochlear Limited (an Australian company).We have an array of information (brochures, booklets and videos) about each. If you use the internet you may wish to visit each manufacturer’s website
From 1 July 2014 newly approved candidates implanted as part of our Minsitry of Health funded programme, both children and adults, will be provided Cochlear Limited devices. Patients who wish to fund their own implants may alternatively elect the MED-EL system.
Is There A Difference Between The Results Of Implantation In Adults And Children?
Children who are implanted at a very young age or adults who became deaf after learning to talk – i.e. with postlingual deafness – respond better to the implant than adults with congenital deafness (born deaf) or prelingual deafness. Although we do not yet know the entire effects of a cochlear implantation on children who were born deaf and implanted later in life, it can be hoped that acoustic sensations will enable these children to incorporate sounds into their lives, and that will be of general benefit to them.
How Can I Help My Child To Use The Cochlear Implant Profitably?
The best way of helping children to use their cochlear implant is to make hearing as interesting as possible for them. This requires a great deal of patience and training. They have to be shown how they can consciously use and evaluate the acoustic information that they receive from their cochlear implant.
What Other Requirements Have To Be Fulfilled Prior To An Implantation?
A medical examination is necessary to ensure that the patient is appropriate to undergo surgery. The patient is likely to have scans of their head to ensure that the cochlear implant array can be inserted. Many Audiological tests are also required to rule out the possibility that the patient could not benefit from a change in hearing aids or additional counseling.
Can The Patient Hear Immediately After The Operation?
No. Without the external coil and the speech processor the patient cannot hear. These components are fitted about 3 weeks after the operation, at the initial tuning session.
Why Is It Necessary To Wait 3-4Weeks After The Operation Before Beginning The Training?
A waiting period is necessary for the operative incision to heal completely. This usually takes 3-4 weeks. When the swelling has subsided, the initial fitting or programming of the processor can be done.
What Happens During The Basic Program?
The basic program consists of 3 phases:
- Adjustment of the device – the device is adjusted until the patient experiences sounds as pleasant.
- Audiological tests are necessary to check whether the adjustment is correct and to find out what the patient perceives, before training is begun.
Familiarization with the use of the device and aural training
How Important Is The Active Cooperation Of The Patient?
The patient’s readiness to experience new and more detailed acoustic impressions and his active cooperation in the training program are of decisive importance for the degree of success. The extent and the duration of the training differ from patient to patient.
Is It Beneficial If Someone Who Is Close To The Patient Takes Part In The Training Program?
If possible, yes. This person should be included in the training program so as to be able to help the patient with his exercises. Such a person should also know how to handle the processor.
How does a cochlear implant work?
Cochlear implants can reconnect those with hearing loss to the world of sound. They work differently to hearing aids, which amplify sound. A cochlear implant transforms speech and other sounds into electrical energy that is used to stimulate surviving auditory nerve fibres in the inner ear.
How a cochlear implant works:
- Speech processor captures then converts sound into a digital signal
- Digital signal is sent through the external coil to the internal implant
- Implant converts digital signal into electrical impulses which are sent along the electrode array, which is inserted inside the cochlea
- Electrodes stimulate the cochlea hearing nerve, bypassing damaged cells, sending impulses to the brain where they are interpreted as sound.