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Cochlear Implants - Implantable Hearing Solution For The Hearing Impaired!

Aster Cmi Hospital 94% (657 ratings)
MBBS & M.S General Surgery
General Surgeon, Bangalore  •  26 years experience
Cochlear Implants - Implantable Hearing Solution For The Hearing Impaired!

A cochlear implant is a small electronic device that can help improve the hearing of people with severe, irreversible hearing loss. Although a cochlear implant does not restore normal hearing, it can allow a person to hear and understand more speech than was possible with a hearing aid.  For a child, this could mean an opportunity to develop listening and speech skills and the potential to attend school with hearing peers. For adults, a cochlear implant could reduce social isolation and improve communication.   

The Implant 
The cochlear implant is a device that is placed in the inner ear.   The implant system has three primary parts:  

  1. Microphone and Transmitter —The headpiece and transmitter is worn above the ear to pick up sounds. These sounds are sent to a speech processor.  
  2. Speech Processor — A speech processor is worn externally, behind the ear like a hearing aid, to convert sound into a digital code that is transmitted to an implanted stimulator.  
  3. Implanted Stimulator — The implanted stimulator is a small component placed under the skin behind the ear. It receives a digital code from the speech processor and sends it to the auditory or hearing nerve. 

The brain interprets this signal and it is recognized as sound.  The small headpiece and transmitter is held in place by a magnet coupled the implanted stimulator, under the skin.  

The Evaluation  
Tests are done to determine if a child is a candidate for a cochlear implantation. Patients are selected based on medical and hearing histories and test results as well as findings.  The evaluation, which differs slightly for children and adults, includes the following:  * 

  1. Medical Evaluation — Conducted by the cochlear implant surgeon who will take the medical history, examine your ears and explain the surgical process.
  2. CT Scan of the Temporal bone and MRI Brain and Cochlear imaging - This computerized tomography (CT) scan allows the surgeon to evaluate the ear's internal structure, recommend which ear to implant and may provide information as to the cause of deafness.
  3. Audiological Evaluation — This evaluation involves a hearing test to confirm the type and degree of hearing loss, hearing aid evaluation to assess the benefit provided by a hearing aid and aided speech recognition testing to determine if a hearing aid might provide greater benefit than an implant.  
  4. Psychological Screening — This screening is conducted by psychologist to assess the feelings about hearing loss and the cochlear implant, such as the reasons for seeking the implant and the expectations.  
  5. Cochlear Implant Counseling — At this time, if one is a candidate for cochlear implant, possible benefits and limitations will be explained and one will be provided with information to select the device.  

Before the surgery, one will meet with an anesthesiologist and and complete any necessary tests. Patients generally remain in the hospital overnight and return home the day after surgery.  

Implant surgery is performed under general anesthesia and takes about three hours. During the operation, a surgeon will anchor a receiver-stimulator device in the temporal bone in the skull and insert what is called an "electrode array" into the cochlea, the small snail-shaped structure in the inner ear that contains the hearing organ.  First, an incision is made behind the ear to expose the temporal bone. The surgeon then positions the implant component against the bone. A hole is made in the temporal bone with a microscopic drill, allowing the surgeon access to the cochlea. A small hole is made in the wall of the cochlea and the electrode array is gently guided into the cochlea. The internal receiver is secured in place on the skull bone with sutures and the incision is closed. A sterile dressing is placed on the incision.  

To qualify for a cochlear implant, patients must meet the following criteria:  
Adults age 18 and older have:  

  1. Overall good health 
  2. Severe hearing loss in both ears 
  3. Limited benefit from conventional hearing aids determined by a trial period, when appropriate, of about three months  
  4. Psychological and emotional stability  
  5. Realistic expectations of the implant  
  6. No ear conditions or other medical conditions that would interfere with surgery  
  7. Ability to participate fully in a follow-up   

Children age 1 to 17 must have:  

  1. Overall good health  
  2. Severe hearing loss in both ears 
  3. Limited benefit from conventional hearing aids  
  4. Realistic expectations of the cochlear implant  
  5. No ear conditions or other medical conditions that would interfere with surgery  
  6. Family commitment to comply with all evaluations before and after surgery  
  7. Enrollment in a post-operative rehabilitative and educational program that supports the use of cochlear implants and the development of hearing skills  

Following surgery, patient will return home for four weeks to allow time for swelling to subside and the incision to heal. After several days, the incision may be wet during bathing or showering.

Device Programming

The externally worn speech processor is activated about four weeks after surgery. The processor converts speech into a special code for each user. The activation and programming is performed at the Hospital. Programming for each implant is customized for the patient and takes about six hours over a two-day period. 

Visit at regular intervals for device checks and re-evaluation. During these visits, the implant and equipment are checked and performance is measured. Re-testing generally occurs at one, three and six months and one year following the initial device fitting. Then, semi-annual or annual evaluations are performed. Each session for adults involves about three hours.  

Benefit from a cochlear implant usually improves with time but can't be guaranteed. Rehabilitation after surgery is key to maximizing the benefits of the cochlear implant. Most people with these implants are able to engage in hearing activities, such as listening to a Walkman, enjoying a movie, using a phone and participating in social activities.  The motivation is critical to the success of the implant. Use the device during all waking hours, Listen, speak and interact with others as much as possible, Utilize visual cues when adjusting to the implant, but gradually decrease the use of visual cues when ready, Ask others to identify unfamiliar sounds so they become familiar.  

Many people have questions about cochlear implants, how they work and what to expect from the surgery. Here are some common questions and answers-

Will a cochlear implant restore normal hearing for people who are deaf? 
No, a cochlear implant does not restore normal hearing. It is a communication tool but not a "cure" for deafness. When hearing functions normally, parts of the inner ear convert sound waves into electrical impulses. These impulses are sent to the brain, where they are recognized as sound. A cochlear implant simulates that process. An implant, supplemented with listening therapy, can help people recognize sound, including speech.  

Are there risks in cochlear implant surgery?  
Risk is inherent in any surgery requiring general anesthesia. However, the surgical risks for cochlear implantation are minimal and most patients require only a one-day hospital stay and have no surgical complications.

Will I need more surgery as new technology becomes available?  
The implanted unit is designed to last a lifetime. The externally worn speech processor, which is responsible for converting sound into code and sending the information to an internal unit, is dependent on software that can be upgraded as technology improves.  

Will my child outgrow the internal device and require a new one?  
No, the cochlea is fully formed at birth and the skull structures achieve almost full growth by age 2. The electrode array is designed to accommodate skull growth in children.  Should I wait for new cochlear implant technology?  No, the design of the surgically implanted receiver and electrode array has changed relatively little during the history of cochlear implants. However, speech-coding strategies, which are responsible for delivering the signal to the internal unit and are stored in the externally worn speech processor, have improved significantly over the years. The speech processor can incorporate new technology when available.  

Can people with cochlear implants identify environmental noises as well as speech?  
Cochlear implants provide a wide range of sound information. Performance in speech perception testing varies among individuals. With time and training, most patients understand more speech than with hearing aids and many communicate by telephone or enjoy music.  

Can people with cochlear implants swim, shower and participate in sports?  
Yes, people with implants can swim, shower and participate in virtually all types of sport activities when they are not wearing the external equipment. The only restriction relates to skydiving and scuba diving because significant changes in air pressure are not advised. Participation in all other athletic activities is unrestricted, although protective headgear is always recommended.  In case you have a concern or query you can always consult an expert & get answers to your questions!

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