What Are Assistive Listening Devices (ALDs)?
You may have certain communication needs that cannot be solved by the use of hearing aids alone. These situations may involve the use of the telephone, radio, television, and the inability to hear the door chime, telephone bell, and alarm clock. Special devices have been developed to solve these problems. Like hearing aids, assistive listening devices make sounds louder. Assistive listening devices can increase the loudness of a desired sound (a radio or television, a public speaker, an actor, someone talking in a noisy place) without increasing the loudness of the background noises. This is because the microphone of the assistive listening device is placed close to the speaker, while the microphone of the hearing aid is always close to the listener. ADLs can be used separately or in conjunction with hearing aids.
Candidates For ALDs
Even people with normal hearing can benefit from ALDs. Some ALDs are used with hearing aids, some are used without hearing aids. Patients who have more severe hearing loss or have fair to poor speech understanding are excellent candidates for assistive listening devices. We performed the first study on adult FM listening devices and all 41 subjects had a significant increase in hearing ability in all 10 different listening environments tested, including noisy restaurants, lecture or sermon, television, and music. The study was published in Hearing Review in 2010.
Types of ALDs
There are many assistive listening devices available today, from sophisticated systems used in theaters and auditoriums to small personal systems.
Various kinds of assistive listening devices are listed below:
Personal Listening Systems: There are several types of personal listening systems available. All are designed to carry sound from the speaker (or other source) directly to the listener and to minimize or eliminate environmental noises. Some of these systems, such as auditory trainers, are designed for classroom or small group use. Others, such as personal FM systems and personal amplifiers, are especially helpful for one-to-one conversations in places such as automobiles, meeting rooms, and restaurants.
TV Listening Systems:These are designed for listening to TV, radio, or stereos without interference from surrounding noise or the need to use very high volume. Models are available for use with or without hearing aids. TV listening systems allow the family to set the volume of the TV, while the user adjusts only the volume of his or her own listening system.
Direct Audio Input Hearing Aids: These are hearing aids with direct audio input connections (usually wires) which can be connected to the TV, stereo, tape, and/or radio as well as to microphones, auditory trainers, personal FM systems and other assistive devices.
Telephone Amplifying Devices: 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 one free hearing-aid-compatible phone from your telephone company. 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 audiologist to get the most appropriate system for your needs.
Cell Phones: Most hearing aids can be used with most cell phones. Importantly, digital hearing aids and digital phones may create constant noise or distortion. There may be significant problems for some hearing aids when used with particular cell phones! The best person to address this problem is your audiologist – speak with your audiologist BEFORE you buy a cell phone or hearing aids.
In spring 2014, the first hearing aids made to interface with your cell phone became available and are very popular among our patients.
Regarding ‘hands free’ systems, there are many to choose from and hearing impaired users usually benefit maximally by using binaural hands free systems. There are many hearing aids that have bluetooth compatibility for use with cell phones as well as TV and other devices.