A person wearing a cochlear implant continues to have restricted hearing. The cochlear implant may improve the perception of speech and sounds, but some very soft sounds remain inaudible. The cochlear implant makes it possible to hear soft sounds, but analysis of these is not the same as with normal hearing. Therefore, a person wearing a cochlear implant has more difficulty understanding speech than a person with normal hearing. In fact, understanding speech in a noisy environment remains difficult even with the cochlear implant and the perception of music is altered.

The perception of sounds with a cochlear implant differs from a hearing aid (more acute, echo, muffed, metallic).
The hearing aid amplifies sounds while the cochlear implant codes them (like a computer) and transmits electrical impulses to the auditory nerve. This is why the brain needs time and auditory training to interpret this new auditory information.

 

Selection criteria evolve according to technological developments and results obtained by cochlear implant users. A cochlear implant can now become an option for individuals who are not completely deaf but whose understanding of speech is significantly affected. An assessment of hearing abilities is essential in determining if a cochlear implant will be of greater benefit to a person than his/her hearing aid.

One can receive a cochlear implant at any age, if the person has a functional oral language . Most importantly, the person must meet the eligibility criteria with regard to receiving a cochlear implant and must be able to undergo surgery.
 

The cochlea is fully formed at birth and does not grow. Nonetheless, the cochlear implant is an electronic device and as such, will need to be replaced at least once during a person’s lifetime.

This is a day surgery that requires general anesthesia. It lasts about 2 hours. 

The internal components are covered with a bio-compatible material (which does not lead to rejection) and the electrodes are made with a special rust-proof metal.

As long as they are not wearing the external device or as long as they are using a proper bathing accessory, cochlear implant users can take a shower, swim and practice most water sports (making sure to respect the time limits recommended by the surgeon following the surgery).  There are restrictions with regard to scuba diving due to variations in water pressure. Participation in all other sporting activities is permitted, although it may be necessary at times to wear a protective helmet.

As soon as the cochlear implant is activated the day after the surgery, the person can hear sounds. However, speech may remain unclear without lipreading. Speech comprehension will improve with the adjustments made during the intensive initial programming period, auditory training and time.

Most adults with a cochlear implant are able to follow a conversation over the phone with a person they are familiar with; but the ease with which they hear may vary. Some may understand a conversation with a stranger while for others, telephone conversations may be very limited, if not impossible. Telephone skills are directly related to the ability to understand speech through hearing only.

Certain limitations to one’s hearing remain, especially when it comes to understanding speech in a noisy environment. People report that they have more difficulty following a conversation in noisy situations than in silence. They must then use more visual cues (lipreading, natural gestures) and communication strategies to understand. The programming may be adjusted to facilitate hearing in a noisy situation; nonetheless, communication remains difficult.

Most cochlear implant users continue to rely on subtitles to complete auditory information. You must bear in mind that background noise or music broadcast during a show, as well as a lack of any possibility of lipreading, can interfere with the understanding of what is said. A sound transmission system may make listening to television easier.

As with television, it may be difficult to understand what is said. Some movie theatres provide transmission systems than can be hooked up to the cochlear implant. 

Even though the cochlear implant provides better hearing, adult speech patterns developed over the years remain hard to change.

The insertion of electrodes in the cochlea usually destroys residual hearing. It is therefore usually no longer possible to use a hearing aid in the ear with a cochlear implant.

Variances in cochlear implant performance were noted in this regard.  Some cochlear implant users enjoy listening to music, while for others the music appears as set of noises. On the other hand, some may identify musical instruments or keep pace, but are unable to recognize the lyrics of a song. Others may recognize words and/or complete sentences of a known and sometimes even unknown song.

Cochlear implant users are no more susceptible to headaches than the rest of the population. However, they must pay a greater level of attention and concentration to auditory information; their level of fatigue may be greater at the end of the day and thus lead to more headaches.

In this regard, one must take into account that these are typically difficult listening conditions : the presence of background noise, several actors who sometimes speak all at once, variable lighting and varying access to lipreading.

Even though the cochlear implant improves comprehension of speech, the environment in which meetings are held may become a hindrance to communication : people speaking all at once or jumping frequently from subject to another, lack of opportunities for lipreading, etc. Therefore, it is important to use appropriate communication strategies and foster good group management.

The ease with which you will understand table talk may vary according to the number of diners, the lighting, the presence of background noise, the opportunities for lipreading and the flow of conversation (people not talking all at once). It is important for the cochlear implant user and his/her parties to adopt appropriate communication strategies.

It depends on the child’s overall development, the level of his/her hearing abilities and the progress of language acquisition. This aspect will be discussed with parents during speech therapy follow-up.

Many factors come into play : the age when the cochlear implant was received, individual potential, the level of hearing and language abilities, and the educational environment. Children with a cochlear implant may have different needs with regard to their schooling (e.g. interpreter, academic advisor, etc.). Most will use an FM system in class.

Very young children with a cochlear implant have a very good chance of developping speech abilities.  They will however normally demonstrate a delay in language acquisition with varying degrees of severity.

It is more difficult to predict the benefits of a cochlear implant for these users.  The results are likely to be more limited, notably because of the long duration of their deafness.  The lack of stimulation of the auditory nerve and brain is among the hypotheses that may explain the weaker implant performance observed in these individuals. 

In general, these adults have more difficulty understanding speech without lipreading.  After several weeks of rehabilitation, they can normally understand simple sentences if spoken slowly.  The use of the telephone may remain difficult or even impossible, and be limited to short conversations with a familiar person.  In exceptional cases, a person belonging to this category may experience hearing performance comparable to the ones experienced by adults who became deaf.

With regard to communication, it is important to point out that the use of a cochlear implant brings about little change to one’s level of speech and language.  Although the person benefits from improved access to speech sounds, articulation habits developed over several years are difficult and perhaps impossible to change.  Despite the motivation and determination observed among many adults, it is unfortunately rare to observe improvements in speech production.  For most people, the cochlear implant will facilitate conversation with the support of lipreading. 

Because accomodating to the new auditory information is often more difficult for this group of individuals, they often require more rehabilitation time.

No one can predict when a revolutionary technique or drug may be discovered. However, current research suggests that it’s unlikely we’ll ever be able to sufficiently regrow the hair cells in the inner ear to restore functional hearing in cases of profound deafness. Moreover, not stimulating the central auditory pathways (brain) for several years will compromise the potential results expected following late cochlear implantation or any possible hair cell regeneration.

Following IFR, most adults are able to understand words and/or sentences with their hearing only (without seeing the lips of the people they are speaking with) in a calm environment. However, the percentage of words and/or sentences recognized, as well as the degree of ease with which they can do so varies from one person to another.  It is difficult to predict the maximal level that can be attained, as several factors must be considered (duration of deafness, pre-implant hearing abilities, etc.). 

It should be noted, however, that cochlear implant performance is influenced by the sound environment.  Indeed, when people find themselves in a noisy environment or in a group (ex: restaurant, family dinner ...), they often have more difficulty understanding speech.  

Most people who receive a cochlear implant experience a significant improvement in their ability to follow conversations with the support of lipreading.  Daily exchanges are also greatly facilitated as they require much less effort. 

With a cochlear implant, people are able to hear (sometimes at the beginning without knowing what it is) low intensity sounds (ex. ticking of a clock, birds, refrigerator humming).  However, a few weeks may be necessary before being able to recognize sounds emanating from the environment (identify what was heard).  

According to several adults, sound with a cochlear implant is different than that heard with a hearing aid or with a normal ear.  For some people, sounds may seem metallic, muffled or sharp, and for others, it comes close to the actual sound.  The appreciation of sounds will evolve over time.  At the beginning of the programming, some people may find sound to be unpleasant, but will get used to it afterwards. Children with a significant degree of deafness since birth have nothing to compare the sounds they are hearing with, as they only experienced limited benefits provided by hearing aids.  It will be for them their way of hearing.

Some people may understand words and/or sentences without lipreading or subtitles. However, as soon as there is background noise or music in a television program, speech becomes much more difficult to understand.  Moreover, it is very arduous to understand translated television programs because one cannot use lipreading.  Consequently, most people resort to assistive listening devices (system that sends television sounds directly to the implant) and/or close captioning (subtitling) to watch television. 

Adjusting to the new auditory information provided by the cochlear implant requires work and perseverance.  However, the benefits gained vary greatly from one person to another and depend on certain characteristics (duration and degree of deafness, use of hearing aids, language level, etc.).  Generally, the more the profound deafness is of short duration, the more the results obtained with the cochlear implant are interesting and appear rapidly.  As such, a person with short duration deafness can refer more easily to his or her auditory memory to make sense of the new sounds heard with the cochlear implant.