Hearing and understanding are to some extent abilities that we have to learn. If hearing loss means that certain high-frequency sounds, for example, are no longer forwarded to the brain, then the brain gradually forgets how to interpret these sounds. It literally forgets how to hear. Part of the hearing spectrum gets lost.
Hearing aids work by amplifying or increasing the volume of sound.
A microphone picks up sound, such as a piece of music, and converts it into an electrical signal and the volume is increased by the amplifier within the hearing aid. A receiver then changes the electrical signal back into sound which is sent into the ear. The hair cells in the inner ear convert the sound vibrations into nerve signals which are picked up by the brain, mimicking natural hearing.
Hearing aids work with your brain.
If sounds in certain frequencies are no longer forwarded to the brain then the brain gradually forgets how to interpret these sounds. Hearing aids will pick up sounds your brain hasn’t processed in a while. It can take time to get used to this – up to 12 weeks depending upon your hearing loss, which is why it is important to persevere with hearing aids, and to stay in contact with your hearing care professional with any concerns or questions you may have.
One of the functions of hearing aids is to act as a kind of "trainer" for the brain in order to regain lost hearing. Soft and high-pitched tones can be audible once more and specific sounds and shades of meaning can be distinguished.
It is important to wear hearing aids early on in the hearing loss process; if your brain does not maintain this “training” some hearing may be lost permanently.