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Assistive Listening Devices for People with Hearing Loss

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What is an assistive listening device, ALD?

The term assistive listening device, ALD, refers to two types of devices. One type helps a person with hearing loss to hear and understand speech better, and the other alerts them to sounds in the environment.   While hearing aids help listeners to hear and understand speech better, they are not considered an ALD.  Generally ALDs are used in place of hearing aids or supplement hearing aids for a particular need.  With the development of digital and wireless technologies, more and more devices are available to help people with hearing loss.  It’s about communicating more meaningfully and participating more fully in daily life.  ALDs are broken into two categories:  devices to improve speech understanding and devices to alert.


What types of assistive devices improve speech understanding?

ALD Logo

Logo used by businesses to indicate ALDs are available.

Devices to improve speech understanding help amplify the sounds you need to hear, especially where there is a lot of background noise. ALDs can be used with a hearing aid or cochlear implant to help a wearer hear sounds better.  There are two categories

    • Large area systems designed for large facilities such as classrooms, theaters, places of worship, and airports.  Large facilities use hearing loop systems, frequency-modulated, FM, systems, and infrared systems. Many large facilities will advertise the availability of ALDs by displaying the international logo for people who are hard-of-hearing.
    • Personal systems intended for personal use in small settings and for one-on-one conversations.



Hearing loop (or induction loop) systems use electromagnetic energy to transmit sound. A hearing loop system involves four parts:

  • A sound source, such as a public address system, microphone, or home TV or telephone
  • An amplifier
  • A thin loop of wire that encircles a room or branches out beneath carpeting
  • A receiver worn in the ears or as a headset

Amplified sound travels through the loop and creates an electromagnetic field picked up directly by a hearing loop receiver or a telecoil.  A telecoil is a miniature wireless receiver built into many hearing aids and cochlear implants. To pick up the signal, a listener must be wearing the telecoil and be within or near the loop. Because the sound is picked up directly by the telecoil, the sound is clearer and without background noise.  Some loop systems are portable, making it possible to connect to a public address system, a television, or any other audio source. For those who don’t have hearing aids with telecoils, portable hearing loop receivers are also available.


FM systems use radio signals to transmit amplified sounds. They are often used in classrooms, where the instructor wears a small microphone connected to a transmitter.  The student listens via a body worn receiver ttuned to a specific channel. People with a telecoil inside their hearing aid use a wire around the neck, neck loop, or next to the hear aid, silhouette inductor, to convert the signal directly.  FM systems transmit signals up to 300 feet and are used in many public places.

Because radio signals penetrate walls, listeners in one room may need to listen to a different channel to avoid receiving mixed signals. Personal FM systems operate in the same way as larger scale systems and can be used to help people with hearing loss to follow one-on-one conversations.


Infrared systems use infrared light to transmit sound. A transmitter converts sound into a light signal and beams it to a receiver worn by a listener. The receiver decodes the infrared signal back to sound. As with FM systems, listeners with telecoil in their hearing aids wear a neck loop or silhouette inductor to convert the infrared signal into a magnetic signal. Unlike induction loop or FM systems, the infrared signal cannot pass through walls. This makes them useful in courtrooms and in buildings where competing signals can be a problem, Because the signal travels on a light beam, infrared systems don’t work well outdoors or in strongly lit rooms.


Personal amplifiers are useful in places where the above systems are unavailable or when watching TV, being outdoors, or traveling in a car. About the size of a cell phone, these devices increase sound levels and reduce background noise for a listener. Some have directional microphones that can be angled toward a speaker or other source of sound. As with other ALDs, the amplified sound can be picked up by a receiver that the listener is wearing, either as a headset or as ear buds. The most popular personal amplifier is the amplified telephone.


What types of assistive listening devices alert?

Alerting devices use sound, light, vibrations, or a combination of these techniques to let someone know when a particular event is occurring. Clocks and alarm systems allow a person to choose to wake up to flashing lights, horns, or a gentle shaking. Visual alert signalers monitor a variety of household devices and other sounds, such as doorbells and telephones. When the phone rings, the visual alert signaler will activate by vibrating or flashing a light. In addition, remote receivers placed around the house can alert a person from any room. Portable vibrating pagers let parents and caretakers know when a baby is crying. Some baby monitoring devices analyze a baby’s cry and light up a picture to indicate if the baby sounds hungry, bored, or sleepy.


What is a telecoil?

A telecoil, also called a t-coil, is a coil of wire that is installed inside many hearing aids and cochlear implants to act as a miniature wireless receiver. It was originally designed to make sounds clearer to a listener over the telephone.  Today it is also used with hearing loop systems, FM systems, infrared systems, and personal amplifiers.

The telecoil works by receiving an electromagnetic signal and turning it back into sound within the hearing aid or cochlear implant. This process eliminates distracting background noise and delivers sound customized for one’s own need.  Listeners who do not have a telecoil-equipped hearing aid can use loop receivers with headsets to provide similar benefits.   However, their signal will not be corrected for their hearing loss.

Many cochlear implants have a telecoil built into the sound processor, or can use an external telecoil accessory with both hearing aid compatible telephones and public loop systems. A simple switch or programming maneuver performed by the user activates this function.

For more information on cell phones, telephones, and hearing aids, see our article titled:  Cell phones, telephones, and hearing aids.  See the NIDCD fact sheet Hearing Aids for more information.


What devices are available for communicating by telephone?

For many years, people with hearing loss have used text telephone called TTY or TDD to communicate by phone. A TTY consists of a typewriter keyboard that displays typed conversations on a readout panel or printed on paper. Callers type messages to each other over the system.  If a call recipient does not have a TTY machine, they use the national toll-free telecommunications relay service at 711 to communicate. For more information, see the Telecommunications Relay Services. Through the relay service, a communications assistant reads typed messages aloud to the person with hearing while transcribing what’s spoken into type for the person with hearing loss. With today’s new electronic communication devices, TTY machines are becoming a thing of the past. People can place phone calls through the telecommunications relay service using almost any device with a keypad, including a laptop, personal digital assistant, and cell phone. Text messaging skips the relay service altogether.

Another system uses voice recognition software and an extensive library of video clips depicting American Sign Language to translate a signer’s words into text or computer-generated speech in real time. It is also able to translate spoken words back into sign language or text.

For listeners with mild to moderate hearing loss, captioned telephones allow you to carry on a spoken conversation.  Captioned phones provide a transcript of the other person’s words on a  screen, while the hard of hearing person talks into the handset.

Finally, the most popular and often used ALD is the amplified telephone.  For listeners who just need more volume to hear on the phone, the amplified telephone can be used with or without a hearing aid to improve speech understanding.


Where can I get more information?

We have one of the best ALD displays in southern Oregon. Most of the devices on display can be purchased the same day you try them. To find out more about available devices, stop in today!

ALD Display

Basin Audiology ALD display


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