About Cochlear Implant
How a Cochlear Implant Device Functions?
A cochlear implant is an electronic device designed to restore the sense of hearing for individuals with severe to profound sensorineural hearing loss. It works by bypassing the damaged parts of the ear and directly stimulating the auditory nerve.
The cochlear implant system consists of two main components: an external sound processor and an internal implant. The external sound processor, worn behind the ear, captures sound from the environment and converts it into digital signals. These signals are then transmitted to the internal implant, which is surgically placed under the skin and attached to an electrode array in the inner ear. An implant has the following parts:
A microphone, which picks up sound from the environment.
A speech processor selects and arranges sounds picked up by the microphone.
A transmitter and receiver/stimulator, receive signals from the speech processor and convert them into electric impulses.
An electrode array is a group of electrodes that collects the impulses from the stimulator and sends them to different regions of the auditory nerve.
The internal implant converts the digital signals into electrical signals and sends them to the electrode array. The electrode array is inserted into the cochlea, the spiral-shaped cavity of the inner ear. The electrical signals stimulate the auditory nerve fibers in the cochlea, bypassing the damaged sensory hair cells that normally transduce sound vibrations into neural signals.
These nerve impulses are then sent via the auditory nerve to the brain, which interprets these signals as sound. This process mimics the natural hearing process, but instead of using sound waves and mechanical vibrations, it uses electrical stimulation.
It’s important to note that a cochlear implant does not restore normal hearing. Instead, it provides a useful representation of sounds in the environment and helps understand speech. The brain needs time to learn or relearn how to interpret the signals received from the cochlear implant, which is why auditory training and rehabilitation are crucial components of the cochlear implant process.
Who is eligible for a cochlear implant?
Cochlear implants are designed to help individuals with severe to profound sensorineural hearing loss. Both children and adults can be candidates for cochlear implants. People who are candidates for this device may have been born deaf or become deaf after learning to speak.
For adults, the general criteria include individuals 18 years of age or older with moderate to profound sensorineural hearing loss in both ears. They should have limited benefit from amplification defined by preoperative test scores of ≤ 50% sentence recognition in the ear to be implanted and ≤60% in the opposite ear or binaurally.
For children aged 2-17 years, the criteria include severe to profound sensorineural hearing loss in both ears and limited benefit from binaural amplification. For children aged 9-24 months, the criteria include profound sensorineural hearing loss in both ears and limited benefit from binaural amplification.
In addition to these criteria, a person’s degree of speech understanding, which is the ability to not just hear but also to distinguish words, is another important factor. Compensating for this degree of hearing loss can cause fatigue and can lead to social withdrawal and depression.
It’s also important for candidates to be willing to learn how to use the implant and be part of the hearing world. They should accept what cochlear implants can and can’t do for hearing.
Preparation for Cochlear Implant Surgery
Preparing for cochlear implant surgery involves several steps to ensure a successful procedure and recovery.
Firstly, it’s important to inform your healthcare provider about all the medicines you are currently taking, including over-the-counter medicines, vitamins, herbs, and supplements. Certain medications, such as ibuprofen, aspirin, or naproxen, may need to be stopped as they can make it harder for the blood to clot.
You may also need to undergo certain tests before the surgery. These could include blood tests or an electrocardiogram to assess your overall health and readiness for the procedure.
On the day of the surgery, follow any directions given by your healthcare provider for not eating or drinking before the procedure. This is usually necessary if you’re going to be given anesthesia during the surgery.
In addition to these steps, it’s also beneficial to prepare your home for your recovery period. This might include arranging for help with tasks that could strain your hand, setting up a comfortable area where you can rest and elevate your hand, and preparing meals in advance.
Remember, each individual’s health situation is unique, so these are general guidelines and may not apply to everyone. Always consult with your healthcare provider for personalized advice on preparing for cochlear implant surgery.
