Providing information to help you hear better

You are here: Home What are assistive listening devices?
What are assistive listening devices?

 

In addition to hearing aids, there are other devices available to help you function better in particular situations.

Assistive listening devices (ALDs) are often recommended if there are specific listening situations where a hearing aid may not be optimal.

The principle of most ALDs is to make the sound take precedent over the background noise, rather than making everything louder. Some ALDs can be used in place of hearing aids and some can be used together.

ALDs can be grouped into three categories – personal devices, group systems and other communication options.
 

Personal Devices

Portable personal listening amplifiers- These are small portable devices that the hearing impaired person can carry and use as required. The person who is speaking talks into a small microphone, which is then amplified and the sound is delivered directly into a headset that is worn by the person with a hearing loss. The volume is able to be adjusted manually to a comfortable level. As only the speakers voice is picked up by the microphone, the negative affects and influence of background noise is reduced. Some situations where a personal listening amplifier may help include restaurants, cars, nursing homes and even meetings.

FM systems- Personal FM Systems comprise two parts – a transmitter microphone used by the speaker and a receiver that is used by the hearing impaired listener. The signal is sent from the transmitter to the receiver via frequency modulation waves (similar to special radio frequencies).

The receiver unit can be used without hearing aids (in a headphone or neck loop), although they are most commonly coupled to the hearing aid for more clear, audible sound. Because FM systems work wirelessly, they have many advantages over other systems – they have a larger range of movement (up to 200 meters), there is less distortion and interference (as they are on a specific designated frequency). Personal FM systems may be quite expensive however.

FM systems can also be used in larger group situations. In these instances the transmitter is usually built in to a microphone system.

Common places where FM systems may be used include lectures, theatres, restaurants, meetings, nursing homes, places of worship, museums, and most commonly the school classroom.

Infrared systems (for TV viewing)-Infrared systems transmit the sound using infrared light waves. They are similar to FM systems, but are often much more affordable. The most common use of an infrared system is for listening to the television. The television volume is set to a comfortable volume for other viewers,the infrared system then transmits the TV signal to a receiver (often headphones) that is worn by the person with a hearing loss. The user is then able to manually adjust the volume to a comfortable listening volume for them, without disturbing the rest of their family! Although TV infrared systems are the most common, infrared systems may also be used in larger settings such as auditoriums and theaters.

Telephone options- There are many different ALDs available to help you hear better on the telephone. The handset of the telephone may be fitted with a telephone amplifier, which can add up to 20dB amplification to the sounds.

A small portable amplifier, is a little adapter that can be attached to the telephone to amplify the sound further. There are also amplified answering machines available and amplified telephones that change the pitch or frequency of the sounds. In most cases these devices can be used with hearing aids or without.

Most modern hearing aids include a feature called a Telecoil (or T switch). This is a small coil located within the hearing aid itself which provides assistance on the telephone, and allows the hearing aid to operate better with the telephone.

In cases of feedback (where the hearing aid whistles) when on the telephone, a coupler may be used. This telephone coupler provides a separation between the hearing aid and the handset and results in less whistling.

 

Group devices

Induction Loop System- An induction loop is a large wire that is permanently installed in a large communal area. The loop is connected to a microphone. When the speaker talks into the microphone, the acoustic sound is changed into an electromagnetic signal and then amplified. Telecoil (or T switches) inside a hearing aid are able to pick up the electromagnetic signal and convert it back into clear audible sound. Although induction loop systems can be purchased for individual use (the loop is often installed under a carpet), they are most commonly found in large group areas such as cinemas, theaters, railway stations, information desks and places of worship.
 

Below is the logo used to indicate an induction loop system is in operation. It is recommended you use your hearing aid on Telecoil.

 

Soundfield Amplification- This ALD system is most commonly found in school classrooms. It is a method of amplifying the teacher's voice using a configuration of microphone and speakers (placed around the classroom). Soundfield amplification helps overcome the effects of distance, noise and reverberation.

 

Other communication options

These are alternative devices that use our other senses, such as touch and vision, to help hearing impaired people function better in their day to day lives. These ALDs are more commonly used by people with a severe to profound hearing loss.

Closed-captioning TV-Most television programmes, as well as DVD’s and videos, have the option of having the spoken dialogue printed on the screen (captions). Many newer TVs have this functionality built in, while other TVs may require an external tele-text decoder box to be purchased.

TTY Telephones- Text telephone or telephone typewriter is a type of ALD that allows people who are hearing impaired to use the telephone to communicate. They are able to type their messages and conversation back and forth between each other, rather than talking and listening. A TTY is usually required by both users, however there is a relay service available if only one person has a hearing loss or uses a TTY

Alarms- Common alarms and ALDs are available to alert the user to doorbells, knocks at the door, telephone ringing, baby crying, smoke detectors, alarm clocks and paging systems. These alarms may use flashing lights, strobe light, conventional light, or vibrations to alert the user.