How hearing aids work?
Our hearing is considered to be one of the most important senses. This is typically because it allows you to be wary of certain dangers that you cannot see. An example might be a car coming around the corner, whereby you will hear the car before you actually see it. Hearing is extremely important when communicating with each other as we usually speak and then listen or vice versa. However, many people are deaf from birth or find that their hearing declines as they become older. This can be an extremely frightening experience, but thankfully we have hearing aids to help us.
Initially it is important to realize how our ears actually hear sounds. Sound can best be described as a form of energy that we are able to hear. Usually when something makes a sound it will typically vibrate and force air molecules to move around far more energetically. This will cause numerous amounts of air molecules to crash into each other and then create sound energy. These specific waves of sound energy will travel in numerous directions until it finally reaches your ears.
The large outer flaps of the ears, known as the pinnae, are actually shaped the way they are in order to gather sounds that comes from numerous directions. It is then able to funnel the sounds directly into the ear canal, which is the hole that leads to your inner ear. You will then find at the end of the ear canal is the eardrum. The eardrum will actually vibrate whenever sound-waves hit them. There are additionally three tiny bones in the skull that can detect vibrations from eardrum and will pass these onto the cochlea. The three tiny bones are known as the hammer, anvil and stapes and the cochlea is a snail shaped organ that is filled with fluid and tiny hairs. The sound vibrations will cause the fluid in the cochlea to travel back and forth while allowing tiny hairs to detect vibrations. This, in turn, will send an electrical signal to the brain which will then be heard as a sound.
Unfortunately, the actual path between your outer ear and brain may become damaged or blocked in a number of ways and this can lead to hearing loss or even somebody becoming deaf. The most common form of hearing loss is due to the hairs in the cochlea becoming damaged. The fewer hairs, the less stimulation that is sent to your brain, thus meaning that sounds will need to be louder in order for you to hear them. This is where a hearing aid is so useful to someone who has impaired hearing. If somebody has suffered from a loss of cochlea hair cells, a hearing aid can make a huge difference.
A hearing aid can best be described as an electronic sound amplifier. In reality they are no different to a person on stage using a microphone, or a person speaking to a large crowd via a loudspeaker. All hearing aids actually contain a microphone, amplifier, a loudspeaker and a battery to power them. However, rather than being as large as a microphone or loudspeaker, they are typically small and discreet and can be worn just behind the ear or even just inside the ear canal.
The most common type of hearing aid is the behind the ear and will typically consist of two separate pieces. Firstly, a hard plastic case that contains a small amplifier, loudspeaker microphone is situated just behind the ear. This will then be linked, via a tube, to a plug known as the ear mould. The mould is shaped to fit inside a person’s ear canal. The microphone will then pick up sounds around you and immediately turn them into an electric current. The amplifier will then be able to boost the size of the current, and the loudspeaker will then turn the original sound into a much louder sound. This amplified sound will eventually make its way into the ear mould. Another style of hearing aid is the in the ear hearing aid. This has exactly the same components, but they are all fitted into one appliance that can be pushed directly into the ear canal. An in the ear hearing aid is extremely discreet and you will often not be able to tell if somebody is wearing one.
There are two main types of hearing aid and these are analogue and digital. An analogue hearing aid will be able to convert sound into electrical currents and boost these currents, before converting them back to make sounds appear louder. Digital hearing aids will typically cost a lot more money and are far more sophisticated. They are known to convert sound into a numerically coded signal prior to turning it back into sound. You can also tune a digital hearing aid to emphasize specific sounds or even block out unwanted noise. Unfortunately analogue hearing aids will simply amplify everything by the exact same amount.
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