Department Of Cochlear Implant
Columbia Asia Hospitals offer cochlear implant for those with hearing loss. The hospital has a dedicated unit where problems related to hearing loss is investigated and treated.Our multidisciplinary team of ENT specialists, cochlear implant surgeons, audiologists,speech pathologists, pediatricians and psychologist are trained in some of the best institutes in India and abroad. The team works with the patient and family and follow internationally accepted protocols intreating hearing loss and use of cochlear implants.
How hearing works?
- Sound wave enter the ear and travel along the ear canal to the ear drum
- Movement of the eardrum makes tiny bones in the middle part of the ear vibrate
- These vibrations are transmitted to a fluid filled part of the inner ear, known as the cochlea
- Tiny hairs lining the cochlea pick up this movement and send electrical signals to the brain, where they are interpreted as sound
How Is Hearing Impaired?
Disease or obstruction involving the ear canal, tympanic membrane (ear drum), or middle ear, may impair conductive hearing. Medical or surgical treatment can probably correct this or a hearing aid can be used in certain patients.An inner ear problem, however can result in a sensorineural impairment or nerve deafness. In most cases, the hair cells are damaged and do not function. Although many auditory nerve fibers may be intact and can transmit electrical impulses to the brain, thesenerve fibers are unresponsive because of hair cell damage. Severe sensorineural hearing loss cannot be corrected with medicine but can be treated with a hearing aid or a cochlear implant.
Signs of hearing loss:
- Failure to respond to sounds
- Reacts only to very loud sound
- In children: in addition to the above two signs, not being able to imitate sounds
- In children: missing normal speech and language development milestones
- Relies on lip reading
- There may be effort of concentration and understanding
What is Cochlear Implant?
Cochlear implant is an electronic device that restores hearing in individuals with severe to profound hearing loss, who do not benefit from a conventional hearing aid.It is surgically implanted in the inner ear and activated by a device worn outside the ear. Unlike a hearing aid, it does not make sound louder or clearer. Instead, the device bypasses damaged parts of theauditory system and directly stimulates the nerve of hearing, allowing individuals who are profoundly hearing impaired to perceive sound.
How a cochlear Implant System works:
- Sound processor: The external sound processor captures sounds and converts them into digital signals
- Coil: These signals are sent from the internal implant, via the coil
- Electrode array: The implant converts the signals to electrical impulses and sends them along an electrode array to the cochlear
- The hearing nerve delivers the signal to the brain. Sound is heard
Benefits of Cochlear Implant:
Cochlear implants are designed for individuals who do not obtain benefit from a hearing aid in terms of speech and language development in a prelingual deafness and hearing and understanding of speech in postlingual patients. They must be 12 months of age or older (unless childhood meningitis is responsible for deafness).ENT consultants with specialized training perform cochlear implant surgery. The cochlear implant team will determine the patient’s candidacy for a cochlear implant and the expected outcome of the procedure.
Steps involved in Cochlear Implant Surgery:
Step 1: Pre-operative evaluation and audiology assessment
The implant team will also conduct a series of tests, including:
- Ear (otologic) evaluation: of the ear canal and middle ear to ensure that no active infection or other abnormality precludes the implant surgery.
- Physical examination: is done to identify any potential problems with the use of general anesthesia needed for the implant procedure.
- Hearing (audiologic) evaluate: The audiologist performs extensive hearing tests to evaluate the type of hearing loss, degree of loss and cause. They assess the speech and language development with and without a hearing aid.
- X-ray (radiographic) evaluation: Special X-rays are taken, usually computerized tomography (CT) and magnetic resonance imaging (MRI) scans, to evaluate the inner ear anatomy.
Step 2: Cochlear Implant Surgery
What Cochlear Implant Surgery Entails
Cochlear implant surgery is usually performed as a Minimal Invasive Technique - VERIA procedure under general anesthesia, single or both ears simultaneouly.An incision is made from the ear upwards and backwards on the scalp.Bone is exposed and a bed created, sufficent to place the implant.Tunnel of 1.6 mm is drilled through the mastoid bone using a special perforator to enter the middle ear. Through the ear canal, the middle ear is exposed and cochlea is opened for the electrode insertion. The patient needs to stay for 24 hrs in the hospital. This technique has a shorter duration of anaesthsia and can be done comfortably in anomalies of middle and inner ear.
Importance of early intervention:
Clinical studies have shown that implantation in early childhood or as soon as possible after the diagnosis of severe hearing impairment,leads to benefits in hearing, speech and language, compared to their non-hearing peers including:
- Ability to develop spoken language
- Increased chance of attending mainstream school
- Enhanced scholastic achievement
- Greater versatility and social robustness
- Successful transition to secondary education
- More opportunities in employment and further education
- Social independence and improved quality of life in adulthood
Step 3: After surgery care involving rehabilitation and speech therapy
What is The Care and Training Needed after the Operation?
Four weeks after surgery, the cochlear implant team places the speech processor and microphone externally. The patient undergoes auditory verbal therapy by a trained specialist following switch-on and mapping. The duration of therapy and repeated mapping depends on an individual. Auditory verbal therapy plays a major role in an implant programme to determine the outcome in that individual.
What Can Be Expected From an Implant?
- There are many factors that contribute to the degree of benefit a user receives from a cochlear implant, including:
- How long a person has been deaf
- The number of surviving auditory nerve fibers
- A patient’s motivation and family support in rehabilitation
- For individuals who lost their hearing after learning to speak, the perception of speech and sound after an implant may initially seem quite different from what they remember. After using the cochlear implant for several months or more, these individuals often report that they perceive speech to be more natural or closer to their memory of familiar sounds
- While many factors affect outcomes for both children and adults;typically, the earlier the implant is done in a child born deaf, the greater the benefit achieved in the areas of speech perception and speech and language development. A predictive factor for implant performance for adults who are deaf is the length of time between the onset of deafness and implant. Those with the shortest duration of deafness tend to experience better outcomes