Assistive Listening Device
A variety of Assistive Listening Device (ALDs), also called Assistive Listening Systems (ALSs) or Hearing Assistive Technology (HAT), are available that can help users hear and distinguish sounds more clearly in different settings. These devices can be used by themselves or in conjunction with a hearing aid or cochlear implant. If you have hearing loss, our audiologists can help you decide whether you a need hearing aids, assistive devicea��or botha��based on your lifestyle and level of hearing loss.
How they work: These devices perform two functions: they amplify sound and bring it directly to the ear, and they separate sounds, particularly speech, from distracting background noise. ALDs consist of three basic components: a microphone, a transmission technology, and a device for receiving the signal and bringing the sound to the ear. The listener wears the receiver, either as a headset or as earbuds.
Transmission methods: ALDs designed for larger, public spaces use one of three transmission methods: frequency-modulated (FM) radio broadcast technology, infrared light-based technology, or inductive loop systems using an electromagnetic field. FM technology is often used in educational settings such as lecture halls, while the infrared technology is suited for situations where the transmission must be contained (such as courtrooms or theaters), because the light cana��t travel through walls. Loop technology is adaptable to a variety of settings, from sports and concert venues to places of worship to homes. Facilities with a hearing loop have a wire encircling its perimeter, which provides a magnetic signal that’s picked up by t-coil-equipped hearing aids, or on a special headset.
Personal amplifiers: In situations where these technologies are unavailable, such as outdoors or in a car, or for smaller spaces, a personal amplifier can help. These devices, about the size of a cell phone, incorporate both a microphone and listening cord. Both the person speaking and the listener use the device, which can increase sound levels and reduce background noise.
Personal FM listening systems also are available, and are helpful in loud conference rooms or restaurants. These systems involve setting a small microphone on the table, with the sound transmitted to the listenera��s hearing aid.
Some people whose listening needs are limited to a particular situation find simple, cost-effective solutions such as a sound amplifier for their television set or telephone.
Telecoil: Most hearing aids, and all cochlear implants, incorporate a coiled copper wire, called a telecoil or t-coil, which functions along with assistive technology devices. Originally designed to work with telephones, telecoils act as an antenna to pick up electromagnetic waves generated by a sound system and deliver them directly to the listener, without the background noise. The hearing aid wearer can turn the telecoil on and off with a switch.
Alert systems: For hearing specific household sounds, solutions include remote signaling devices that set off an alarm when the doorbell or phone rings, for example, or a smoke detector goes off. Some signaling devices, including specially designed alarm clocks, use a strobe light, or are connected to a vibrator attached to a mattress, pillow or wrist.