How does a hearing aid work?
A hearing aid takes in sound through the microphone, sends it through filters to amplifiers, which send it to a receiver. The clean and amplified sound is then placed into the ear canal. The sound must travel through the ear canal to make the eardrum vibrate. The ear drum movement causes the bones of the middle ear to vibrate, which then sends the sound to the inner ear (cochlea). The inner ear has hair cells that help to transmit the sound to the nerve. When these hair cells are damaged, they cannot send a clear signal to the hearing nerve. Even though the sound coming from the hearing aid is clear, if the cochlea is damaged, it will not be able to process the sound clearly.
A hearing aid is an electronic device with a small microphone that amplifies weak sounds through a small speaker. The speaker directs sound directly into the ear canal. You must have some ability to hear for the device to work. Modern aids are programmed to boost only those frequencies that are affected by the wearer. Typically, this means that the higher range of frequencies are boosted, while low to midrange frequencies are left unchanged. Again, due to the advanced electronics in most modern devices, there is a capability to discriminate background noise from speech, which improves satisfaction on the part of the wearer.
download the pdf All hearing aids have the same basic parts. In the behind-the-ear hearing aid shown here, you can see the microphone, the tonehook or earhook, the volume control, the on/off switch and the battery door. The microphone picks up sounds and sends them to an amplifier that makes them louder. The hearing aid will make some pitches of sound louder than others, depending on the shape of the hearing loss. Your audiologist uses the hearing aid’s internal controls or computer programming to adjust the sound for your child’s needs. earmold After sounds are made louder, they go through the earhook to an earmold that is custom made for your child. The earhook is a small plastic piece that holds the hearing aid on the ear. Earmolds are made from a mold or impression of your child’s ear. They are made from soft materials and fit in the outer ear and ear canal. Since it is so important for earmolds to fit snuggly in the ear, they will need to be replaced as your baby grows.
One of the natural processes of aging is hearing loss. Hearing aid devices assist the user in hearing noises in the higher range. Losing hearing in the higher range is often the first sign on hearing loss. Inside the ear canal are the cells (called hair cells) that catch sound in vibration form. The cells convert the vibration to neural signals with transfer to the brain. Aging reduces the length of these hair cells which cause less vibration. Hearing Aids contain three parts: a microphone to pick up the sound, an amplifier to amplify the sound and a speaker to allow the hair cells to respond to the brain. Basically, a hearing aid magnifies the sound entering the ear.
