The earliest hearing aid is still in use today – one’s hand, cupped behind the ear. In the 17th century, the first mechanical hearing aid was created, called The Metal Ear, and it was exactly what it sounds like, fashioned of metal and worn over the ears. By the 19th century, ear trumpets had come into fashion. The first modern hearing aids emerged from the invention of the telephone; its ability to capture sound, turn it into electrical energy and amplify it.
Hearing aids worn outside the ear
- Body-worn hearing aids. These devices consist of two parts: an earmold speaker worn in the ear, attached to a remote device about the size of a pack of playing cards that receives and amplifies sounds, and is worn in a pocket or elsewhere on the body. These devices feature long battery life, high amplification and low price.
- Behind-the-ear hearing aids. These are also two-part devices. The receiver fits on top of and behind the ear, and is connected to an earmold speaker worn in the same ear.
- Eyeglass hearing aids. Similar to the behind-the-ear design, these aids contain the receiver/amplifier in the frame of the wearer’s eyeglasses.
- Open-fit devices. Also called “over the ear” devices, these are a variant of the behind-the-ear design that some wearers find more comfortable because the speaker also fits outside of the ear, as opposed to being inserted into it like an earmold. This design allows amplification of sounds without the “blocked up” feeling that wearers of earmolds sometimes experience.
Hearing aids worn inside the ear
- In-the-ear hearing aids. With this design, the battery, receiver/amplifier, and earphone are all contained in a shell that fits into the outer part of the ear. Smaller than the behind-the-ear devices, these aids are less visible. They are also often considered more comfortable by many wearers than smaller in-the-canal devices.
- Full-shell and half-shell hearing aids. These are variants of the in-the-ear design in which the receiver/amplifier part of the device is custom-fit to the bowl-shaped area of your outer ear.
- In-the-canal hearing aids. These are the smallest hearing aids generally available, and fit either partially or entirely in the ear canal. They have advantages in that they are almost invisible, pick up less wind noise, and make it easier to use telephones.
Other types of devices are available, such as disposable hearing aids that are discarded after the battery wears out, or Bone-Anchored Hearing Aids (BAHA) that conduct sound by bone conduction via a surgically-implanted prosthetic.