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Assistive Listening Devices
Cochlear implants benefit persons born with severe to profound hearing loss or do not receive benefits from hearing aids. Cochlear implants have an external portion that sits behind the ear. There is a second portion (receiver) that is surgically placed under the skin. A microphone picks up the environmental sounds while the external speech processor selects and arranges those sounds which are then transmitted to the internal receiver. The receiver converts the signals into electric impulses which are then sent to the auditory nerve. Here is a great explanation with pictures. Normal hearing is not restored, but a cochlear implant can help a person understand speech.
Digital Hearing Aids
Digital refers to Digital Audio Processing (DAP). A hearing instrument that is truly digital converts an analog sound wave into digital code, a series of 0s and 1s. Specific sections of coded or digitized sound can then be isolated and processed or amplified based upon the specific hearing loss and listening preferences of the user. In addition, a truly digital hearing instrument does not add noise to the signal as it passes through the electronic circuit. A DAP hearing instrument is virtually distortion free. "Digital" is often confused with a "computer" hearing instrument. The latter always refers to the way the controls of the hearing instrument are set using a computer or programming box. This has nothing to do with the way the sound signal is processed which distinguishes a true digital hearing instrument.
Digital hearing aids aren't superior because they're digital but because of the enhanced features available. See this article from the American Speech-Language-Hearing Association for an explanation of the features that digital hearing aids provide.
See the resources section below for two companies that carry digital hearing instruments. (There are many.)
Super Voice Recognition
Hearing aids are worn in all situations, whereas an assistive listening device (ALD) is made to enhance listening through amplification in specific situations—on the telephone, at a theatrical or concert performance, at a lecture, for televisions, etc. In practice, the ability to selectively amplify signal, but not background noise, is the biggest advantage of an assistive listening device. Some are compatible with hearing aids. ALDs also compensate for less than ideal acoustics.
So What's What in ALDs?
Infrared systems transmit sound through light waves to receivers worn by users. They are typically found in courtrooms, movie theaters, and playhouses. They are susceptible to interference from bright light.
FM radio systems transmit radio waves to receivers and work well in classrooms when the speaker (or sound source) moves around a lot. They are susceptible to light and radio interference. Sound field systems, or speakers, are also utilized in similar situations and are helpful to persons with mild or moderate hearing loss. Sound field systems can be used with FM receivers that connect to the ear.
Inductive or audio loop systems transmit through an electromagnetic field and require no receiver if the hearing aid wearer has a telecoil. Receivers can be provided for others. They are susceptible to EMI interference.
Coupling devices, such as headsets, earbuds, and neck loops are also helpful. Sometimes you may attend a conference or lecture where a CART System is used (computer assisted real-time transcription). A stenographer types what is being said verbatim and it is converted into English (or another spoken language such as Spanish) and displayed on a monitor or screen. The CART System requires a fast, accurate typist who can summarize. There are various systems that accomplish the transcription, such as C Print and computer assisted note-taking (CAN).
Vendors & Resources
Assistech Special Needs
Assistive Listening Device Systems Inc.
Audiology Awareness Campaign
Consumer Affairs Hearing Aids Reviews
Global Assistive Devices, Inc.
Sound Choice Assistive Listening, Inc.
Note: Infinitec Inc. does not endorse or recommend these products and has no liability for the results of their use. Infinitec Inc. has received no consideration of any type for featuring any product on this Web site. The information offered herein is a summary; it is not comprehensive and should be carefully evaluated by consumers with the assistance of qualified professionals. The intention of Infinitec Inc. is to offer consumers a brief overview of various assistive technology devices and their applications.