People with all types and degrees of hearing loss, even people with normal hearing, may benefit from an assistive listening device (ALD). Since the microphone of a typical hearing aid is worn on or behind your ear, its ability to enhance the talker-to-background noise ration is limited. However, ALDs are designed to increase the loudness of a desired voice, such as a radio, television, or a public speaker, without increasing the background noise. This is because the microphone of the assistive listening device is placed close to the talker or device of interest, while the microphone of the hearing aid is always close to the listener.
Assistive listening systems (ALS) or assistive listening devices (ALD) are amplifiers that bring sound to the ear and separate sounds such as speech from background noise. ALSs improve speech to noise ratio improving the level of understanding for people who have problems distinguishing speech in noise to the same level of people with normal hearing ability.
Many types of ALDs are available for home use and larger public facilities. Some ALDs include alarm clocks, TV listening systems, telephone amplifying devices, and auditorium-type assistive listening systems. Many newer devices are small, wireless and compatible with a person’s digital hearing aids. The ALD may be something small that attaches directly to the hearing aid, is activated through a program in the hearing aid, or is worn around the neck and transmits sounds wirelessly to the hearing aids. Alarms and other home ALDs may be small devices that are placed discreetly on tables, next to the TV or on the wall. Please refer to the hearing aid manufacturers’ pages for examples of ALDs.
Telephone amplifiers increase the volume of your telephone. They attached directly to the telephone headset and have built-in volume control. Most, but not all, standard telephone receivers are useful with hearing aids. These phones are called “ hearing aid compatible.” The option on the hearing aid is called the T-Coil. The T-coil is automatically activated on some hearing aids and manually activated on others. Basically, the telephone and the hearing aid’s T-coil communicate with each other electromagnetically, allowing the hearing aid to be used at a comfortable volume without feedback and with minimal background noise. You should be able to get hearing-aid-compatible phones from your telephone company or almost any retail store that sells telephones. Not all hearing aids have a “T” switch. Make sure your hearing aids have a T switch before purchasing a new hearing aid compatible phone! There are literally dozens of T-coil and telephone coupling systems. Speak with your Hearing Health Care Provider to get the most appropriate system for your needs.
FM ALDs use radio broadcast technology. They are often used in educational settings and offer mobility when used with portable, body-worn transmitters.
Infrared ALDs use light-based technology. They guarantee privacy because infrared does not travel through walls. They are typically used for entertainment such as television listening because they are frequently installed in places of entertainment.
Inductive loop ALDs use electromagnetic field to deliver sound. They do not require a body-worn receiver and can also be used by non-hearing aid users through headphones and inductive loop receivers.
As with any hearing aid accessory, a hearing professional can help you decide which ALD is right for you.