Assistive Listening Devices
Assistive listening devices (ALDs) or assistive listening systems include a large variety of devices designed to help you hear sounds in everyday activities. They are FDA-regulated as medical devices and electronic products. ALDs are available in some public places such as auditoriums, movie theaters, houses of worship, and meeting rooms. Normal hearing and hearing-impaired people may use ALDs to improve listening in these settings.
ALDs can also be used to hear better from distances, poor room acoustics, and background noise. Many ALDs have a microphone near the source of the sound and a receiver near the listener. The listener can adjust the volume of the receiver as needed. The microphone placement allows the level of the speaker’s voice to stay constant despite the distance between the speaker and the audience. The speaker’s voice is also heard clearly over room noises such as chairs moving, fan motors running, and people talking. ALDs can be used with or without hearing aids.
Cochlear Implants
A cochlear implant is an implanted medical device that can produce useful hearing sensation by electrically stimulating nerves inside the inner ear. Cochlear implants currently have two main components.
- The external component includes an externally worn microphone, sound processor and transmitter system.
- The internal component includes an implanted receiver and electrode system which contains the electronic circuits that receive signals from the external system and send electrical signals to the inner ear.
Cochlear implants have some differences from hearing aids.
| Hearing Aids | Cochlear Implants |
|---|---|
| Hearing aids are indicated for individuals with all degrees of hearing loss, from mild to profound. | Cochlear implants are indicated only for individuals with severe to profound hearing loss. |
| Most hearing aids are not implanted. Although, some hearing aids can have an implanted component. | Cochlear implants have internal (implanted) and external components. A surgical procedure is needed to place the internal components. |
| In hearing aids, sound is amplified and conveyed through the outer and middle ear and finally to the sensory receptor cells (hair cells) in the inner ear. The hair cells convert the sound energy into neural signals that are picked up by the auditory nerve. | Cochlear implants bypass the outer and middle ears and the damaged hair cells and replace their functions by converting sound energy into electrical energy that directly stimulates the auditory nerve. |
Implantable Middle Ear Hearing Devices
Implantable Middle Ear Hearing Devices (IMEHD) help increase the transmission of sound to the inner ear. IMEHDs are small implantable devices that are typically attached to one of the tiny bones in the middle ear. When they receive sound waves, IMEHDs vibrate and directly move the middle ear bones. This creates sound vibrations in the inner ear, which helps you to detect the sound. This device is generally used for people with sensorineural hearing loss. IMEHDs are medical devices.
Bone-Anchored Hearing Aids
A bone-anchored hearing aid (BAHA), like a cochlear implant, has implanted and external components. The implanted component is a small post that is surgically attached to the skull bone behind your ear. The external component is a speech processor which converts sound into vibrations. It connects to the implanted post and transmits sound vibrations directly to the inner ear through the skull, bypassing the middle ear. BAHAs are for people with middle ear problems, usually a mixed hearing loss or who have no hearing in one ear. BAHAs are medical devices.
Personal Sound Amplification Products
Personal Sound Amplification Products (PSAPs) are intended to amplify sounds in certain environments for non-hearing-impaired listeners. PSAPs are often used when hunting (listening for prey), bird watching, listening to lectures with a distant speaker, and listening to soft sounds that may be difficult for normal hearing individuals to hear, like distant conversations. Unlike hearing aids, PSAPs are not intended to aid with or compensate for hearing impairment. Although PSAPs are electronic products, which are products that the FDA regulates under the Electronic Product Radiation Control Program, they are not medical devices like hearing aids.
Source: https://www.fda.gov/medical-devices/hearing-aids/other-hearing-devices-and-products#1
