To make a hearing aid, an audiologist or hearing aid dispenser will make an imprint of the patient's ear by pouring silicon material into the ear. Once it hardens, the silicon imprint is removed from the ear and sent to the manufacturer to make the hearing aid.
The imprint is used to make a silicon mold, which is filled with acrylic and hardened in an ultraviolet oven. This creates the shell of the hearing aid. Holes are drilled into the hearing aid, and the electrical components -- volume control, microphone and speaker -- are placed inside. A group of wires is attached to all of the different electronic parts and the battery is installed. When the hearing aid is finished, it is polished smooth and then analyzed to make sure that it fits the patient's hearing prescription.
Hearing Aid Parts
Hearing aids are fairly simple devices, consisting of four basic parts:
- A microphone picks up sound from the environment and converts it into an electrical signal, which it sends to the amplifier.
- An amplifier increases the volume of the sound and sends it to the receiver.
- A receiver/speaker changes the electrical signal back into sound and sends it into the ear. Then those impulses are sent to the brain.
- A battery provides power to the hearing aid.
Hearing aids aren't effective for everyone. Hair cells in the inner ear must pick up the vibrations that the hearing aid sends and convert those vibrations into nerve signals. So, you need to have at least some hair cells in the inner ear for it to work. And, even if some hair cells remain, a hearing aid won't completely restore normal hearing.