A Cochlear Implant is a small sophisticated electro-medical Hearing Device. It helps people with Severe to Profound Sensorineural Hearing loss to hear sounds. This device is generally recommended if conventional Hearing aids do not benefit.
Why does one need a Cochlear Implant and not a Hearing Aid?
This is a basic question asked by most people when advised a Cochlear Implant. Hearing aids do not help some people suffering from Severe or Profound hearing loss. For them, the speech is not clear with Hearing aids. The sound amplified by the Hearing aid does not help as the Cochlea is not functioning normally. These people may find cochlear implants as the means to hear sounds. Read this article on Cochlear Implants vs Hearing Aids to understand the differences.
Let us understand the functioning of the Cochlea. This will help us to understand how a Cochlear Implant works.
How Does The Human Cochlea Function?
Let us understand the working of the Inner Ear in brief. The Cochlea is a snail-shaped organ in the Inner ear. There are thousands of tiny hair cells in the inner part of the Cochlea. These hair cells are responsible for converting sound waves to electrical impulses. In case of damage to the Cochlea. The hair cells do not convert the sound vibrations to electrical pulses.
The Auditory Nerve
The Auditory Nerves carry the electrical pulses from the Cochlea to the brain. Partial or full damage to the Cochlea reduces the sound signals reaching the brain. This results in Hearing loss or reduced hearing ability.
What is the Advantage of a Cochlear Implant?
A Cochlear Implant is suitable for people with Inner ear damage. It provides direct electrical stimulation to the Cochlea in the Inner ear. It bye-passes the Outer Ear and the Middle Ear to directly reach the Cochlea. In other words, The Cochlear Implant does the job of the Cochlea.
How does a Cochlear Implant Work?
Cochlear Implants can be broadly divided into two main parts. The external part which is normally visible. And the internal part which is surgically transplanted under the skin. The external part picks up the sound and processes them. The Internal part carries the processed sound signals and delivers them to the Inner ear. Both these parts work together which enables the user to perceive or hear the sound.
Parts of Cochlear Implant
The Cochlear implant consists of two parts. The external visible part and the internal part.
External Parts of the CI
The Speech Processor unit with the Microphone
The Speech Processor is an external part. It sits behind the ear in a casing which looks the same as a BTE Hearing Aid. This contains the microphone and the sound processing circuit. The wires and the Transmitter are also the external parts.
Functions of the External Parts of the CI
The primary function of the Microphone is to pick up the sound. Same as the microphone in a conventional Hearing aid. These sound signals are then passed on to the Speech Processor.
The Speech Processor
The Speech processor processes the sound signals received from the Microphone. The Speech processor is a small digital computer. It analyses and processes the sound signals. The processing of the sound signals is as per the hearing capacity of the user. After processing, the signals pass on to the transmitter.
Speech processor Housing
The Speech Processor is generally situated in the same housing as the microphone. The housing is slightly bigger in size to a BTE hearing aid. With regular research in this area, the housing may become as small or much smaller. In some models, the processor is in the shape of a small box and kept in the shirt chest pocket.
The wires from the speech processor carry the signal to the Transmitter. The transmitter has a coil which radiates the signal. It stays in place with the help of a magnet. The receiver transplanted under the skin also has a magnet. The magnets of the transmitter and the receiver hold each other. The transmitter receives signals from the processor and sends them to the receiver.
Internal Parts of the CI
The other parts of the Cochlear Implant are internal and placed under the skin. This process requires a surgery or implantation by an ENT Doctor.
The main parts are
Electrodes or Electrode Array
Functions of the Internal Parts of the Cochlear Implant
The two internal parts are surgically transplanted under the skin. These are the Receiver and the Electrodes.
The transplanted receiver is under the skin behind the ear. This receiver has a coil which picks up the signals given out by the transmitter.
Electrodes or Electrode Array
The Receiver passes the signals on to the array of electrodes in the form of electrical signals. These electrodes have been surgically inserted into the Cochlea. They are also called Electrode Array as there is more than one electrode. The electrical signals or impulses stimulate the Cochlea. This stimulation results in the perception of sound.
The speech and sound signals picked up externally reach the Cochlea. Hence the name Cochlear Implant.
Precaution is better than cure
With early detection, we can stop the progress of Hearing Loss. Consult your Doctor immediately to prevent further damage. Please note that the Cochlear Implant does not cure the hearing of the affected person. To some extent, it restores the ability to hear the sensation of sound.