Assessing Student's Needs for Assistive Technology (ASNAT)

Chapter 8 – Assistive Technology for Vision and Hearing
Assisted Listening Devices
Assisted Listening Devices are amplification systems that are designed to enable the person who is deaf
or hard of hearing to participate in different situations through the awareness and/or recognition of
sounds. The purpose of an ALD is to increase the signal input and reduce the background noise. There
are several types of ALDS, personal amplification systems, FM systems, loop systems, and infrared
systems. Personal preference plays a large roll in the choice and use of an ALD. The following are a list
of ALDS.
♦ Personal Amplification Systems-These are often most helpful to individuals who are hard of
hearing. They are most useful in one-to-one communication situations, car rides, and when watching
TV. These are usually small like a walkman, with a microphone and a choice of headset. The basic
unit is an amplifier that can be used with a hearing aid if it has the T-Coil.
♦ Hearing Aids-There are several types of hearing aids; behind-the-ear or in-the-ear are the most
common. The new ones are electronically programmable, enabling the audiologist to set the
amplification per frequency as determined by the hearing test. Hearing aids do not make sound
clearer, just louder. Think of a hearing aid as the volume control of a radio. If the radio is not set
exactly on the station there is static. When you turn up the volume it increases not only the desired
signal (speech, music) but also the static. Most hearing aids come with the option of a T-Coil
(telecoil). This coil is to amplify sound from electronic devices, such as telephones. If a person is
hard of hearing and is dependent upon speech for communication, a Telecoil is a must. A hearing aid
is an electronic device and sweat can ruin it. It is a good idea to purchase a dehumidifier for the
hearing aid. These are pocket size and usually cost under $10.00.
♦ FM Systems-These are usually found in movie theaters, conference halls and classrooms. An FM
system transmits sound using radio waves. The speaker wears a microphone and a transmitter
(walkman size) while the listener uses a headset and receiver. Individuals who have a telecoil in their
hearing aid can use this feature. FM signals are not limited to one room; the sound can go through
the wall or the ceiling. If there are 2 different FM transmitters within an area, they need to be on
different frequency channels.
♦ Loop Systems-The person must have a hearing aid with a telecoil to benefit from a loop system. A
loop wire is placed under a carpet circling a specific listening area. The hearing impaired person
must sit within the looped area. The speaker uses a special microphone and amplifier. The loop
system picks up the speech and amplifies it within the telecoil of the hearing aid. These are easy to
install and the sound is accessed only by those within the looped area and who are using a hearing
aid with a telecoil. These systems are commonly found in theaters, conference rooms and
classrooms.
♦ Infrared Systems-Infrared systems transmit sounds through invisible light beams. To work, the
receiver must be in the direct line of sight of the transmitter. The sound stays within the room. The
system cannot be used outside due to sunlight interference. Sometimes really bright incandescent
light may interfere. These systems are commonly found in classrooms and conference centers.
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