Assistive listening devices, or assistive listening technology, are any devices that help a person with hearing loss to communicate.

The development of digital and wireless technologies means more and more devices are becoming available to help those with hearing disorders to communicate more meaningfully and participate more fully in their daily lives.

What types of assistive listening devices are available to me?

You have several choices when it comes to choosing and ALD to improve sound transmission, no matter your lifestyle. These devices are designed for various venues including, large facilities such as classrooms, theaters, places of worship, and airports. ALD systems for large facilities include hearing loop systems, frequency-modulated (FM) systems, and infrared systems (read more below). Other types are intended for personal use in small settings and for one-on-one conversations. All of these devices can be used with or without hearing aids or a cochlear implant.

Hearing loops

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

• A sound source, such as a public address system, microphone, or home TV, or telephone (this picks up the sound)
• A sound amplifier, which processes the signal
• A thin loop of wire that encircles a room or branches out beneath carpeting
• A receiver is worn in the ears or as a headset

Amplified sound travels through the loop and creates an electromagnetic field that is picked up directly by a hearing loop receiver or a telecoil, a miniature wireless receiver that is built into many hearing aids and cochlear implants. A listener must be wearing the receiver and be within or near the loop to pick up the signal. Because the sound is picked up directly by the receiver, the sound is much clearer, without as much of the competing background noise associated with many listening environments. Portability is an option. Some loop systems are portable, making it possible for people with hearing loss to improve their listening environments, as needed throughout their daily lives. A hearing loop can be connected to a public address system, a television, or any other audio source. Portable loops receivers are also available for those who don’t have hearing aids with embedded telecoils.

Telecoils

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. It also is used with a variety of other assistive listening devices, such as hearing loop (or induction loop) systems, FM systems, infrared systems, and personal amplifiers. The telecoil works by receiving an electromagnetic signal from the hearing loop and then turning it back into sound within the hearing aid or cochlear implant. This process eliminates much of the distracting background noise and delivers sound customized for one’s own need. For people who are hard-of-hearing who do not have a telecoil-equipped hearing aid or cochlear implant, loop receivers with headsets can provide similar benefits but without the customized or “corrected sound” feature that matches one’s hearing loss pattern. 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.

FM Systems

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. The goal of a telecoil is to enhance and ‘clean up’ the speech signal coming through the audio system, whether it be a telephone or a microphone, such as in an auditorium or airport. It also is used with a variety of other assistive listening devices, such as hearing loop (or induction loop) systems, FM systems, infrared systems, and personal amplifiers. The telecoil works by receiving an electromagnetic signal from the hearing loop and then turning it back into sound within the hearing aid or cochlear implant. This process eliminates much of the interference of background noise and delivers sound customized for the person wearing the device. For those who are hard-of-hearing and do not have a telecoil-equipped hearing aid or cochlear implant, loop receivers with headsets can provide similar benefits but without the customized or “corrected sound” feature that matches one’s hearing loss pattern. Many cochlear implants have a telecoil built into the sound processor or can utilize an external telecoil accessory with both hearing aid compatible telephones and public loop systems. The user can activate this function through a basic programming maneuver.

Infrared Systems

Infrared systems use infrared light to transmit sound, which can be optimally used in difficult listening situations. A transmitter sends sound into a light signal and beams it to the hearing-impaired individual. The individual / receiver decodes the infrared signal back to sound. As with FM systems, people whose hearing aids or cochlear implants have a telecoil may also wear a neckloop or silhouette inductor to convert the infrared signal into a magnetic signal, which can be picked up through their telecoil. Unlike induction loop or FM systems, the infrared signal cannot pass through walls, making it particularly useful in courtrooms, where confidential information is often discussed, and in buildings where competing signals can be a problem, such as classrooms or movie theaters. However, infrared systems cannot be used in environments with too many competing sources of light.

Personal Amplifiers

Personal amplifiers are useful in places in which the above systems are unavailable or when watching TV, being outdoors, or traveling in a car. These devices increase environmental 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. The amplified sound can be picked up by a receiver that the listener is wearing, either as a headset or as earbuds.

What devices can I use to communicate via telephone?

For decades, people with hearing loss have used text telephone or telecommunications devices, called TTY or TDD machines, to communicate by phone. This technology also benefits people with speech difficulties. A TTY machine consists of a typewriter keyboard that displays typed conversations onto a readout panel or a printed piece of paper. Callers will either type messages to each other over the system or, if a call recipient does not have a TTY machine, use the national toll-free telecommunications relay service at 711 to communicate (See Telecommunications Relay Services for more information). Through the relay service, a communications assistant serves as a bridge between two callers, reading typed messages aloud to the person with hearing while transcribing what’s spoken into type for the person with hearing loss. People can place phone calls through the telecommunications relay service using almost any device with a keypad, including a laptop or cell phone. With today’s ever-changing technological advances, communication methods such as text messaging have served similar functions to the TTY. 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. This system is also able to translate spoken words back into sign language or text. For those with mild to moderate hearing loss, captioned telephones allow you to carry on a spoken conversation, while providing a transcript of the other person’s words on a readout panel or computer screen as back-up.

What types of alerting devices exist?

Alerting or alarm devices use sound, light, vibrations, or a combination of these effects to let someone know when a particular event is occurring. Clocks and wake-up alarm systems allow a person to choose to wake up to flashing lights, vibrations, or ring tones. Visual alert signalers monitor household devices and other sounds, such as doorbells and telephones. When a phone rings, the visual alert signaler will be activated and will vibrate or flash a light to communicate this message. In addition, remote receivers placed around the house can alert a person from any location in a house. Portable vibrating pagers can alert parents and caretakers when a baby is crying. Some baby monitoring devices can even analyze a baby’s cry and light up a picture to indicate if the baby sounds hungry, bored, or sleepy.

What research is being conducted on assistive technology?

Researchers are actively developing technological devices to help people with hearing loss communicate with the world around them. Notably, a team of researches has developed a portable device in which multiple users can communicate and type messages to each other in real time. This field of research is inspired and dedicated to advancing technology in hopes of enhancing the rich lives of those with hearing loss.