What Are Cochlear Implants and How Do They Work
According to the World Health Organization (WHO), about five percent or 360 million of the world’s population suffers from hearing loss. This includes 318 million adults and 42 million children. Despite a large number of people suffering from hearing loss, many people either do not have access to or are not willing to use corrective measures.
However, there are several corrective measures that can help people suffering from hearing loss (mild to severe) to hear better and one is the cochlear implant.
What is a cochlear implant?
A cochlear implant is a small electronic device that is surgically implanted behind the ear and under the skin of people who are profoundly deaf or severely hard of hearing. A cochlear implant doesn’t cure hearing; instead, it helps patients suffering from sensorineural hearing loss (damaged hair cells impeding sound to reach the auditory nerve) to treat hearing loss.
How does it work?
Since, the tiny hair cells in the cochlea are damaged, cochlear implants skip them entirely and send the sounds directly to the auditory nerves.
The Cochlear Implant consists of an external portion that goes behind the ear and an internal piece that is surgically implanted under the skin. It consists of a:
- Microphone: The microphone looks a lot like behind the ear hearing aid. The microphone picks up the sound, much like hearing aid microphones, and sends them to the speech processor.
- Speech processor: The speech processor is either attached with the microphone or, more commonly, shaped like a box and kept in the chest pocket. The speech processor selects, analyzes and digitizes the sounds picked by the microphone.
- The transmitter and receiver/stimulator: The transmitter is worn on the head behind the ear while the receiver is implanted under the skin. It receives signals from the speech processor and converts them to electric impulses.
- Electrode array: Electrode array is also implanted under the skin and in the cochlea. It collects electric impulses and stimulates the fibers in the different regions of the auditory nerve. This creates the perception of sound.
Who should get a cochlear implant?
Both adults and children, who are deaf or severely hard of hearing, can get cochlear implants.
Eligible adults who:
- Have severe or profound hearing loss
- Have already used hearing aids but did not benefit from them
- Had already learned speech and language before suffering from hearing loss
- Have a strong desire to be part of the hearing world
Adults who get these implants already recognize speech and language, so they associate the sound provided by the cochlear implants with the sound they remember. They, then, don’t need visual cues such as lip reading to understand the speech.
However, children can also get cochlear implants. FDA has approved children aged 12 months and up to get cochlear implants. Most babies who have been diagnosed with hearing loss get the implants as soon as possible. This is due to the studies conducted by researchers that concluded children who get cochlear implants early in life do much better than those who get it later in life.
Cochlear implants work best for children who:
- Have profound hearing loss in both ears
- Are not able to benefit from hearing aids
- Do not have a medical condition that can bar surgery
- Are willing to learn how to communicate with a cochlear implant
- Have a support system in their parents, school and teachers
In addition, children who get a cochlear implant before 18 months of age learn to speak, hear and learn much faster than those who get it later. Some even develop these skills at the rate comparable to the kids with normal hearing.