Assistive Listening Devices

An assistive listening device or ALD is any device that helps people function better in day-to-day communication situations. An ALD can be used with or without hearing aids to help people with hearing loss overcome the negative effects of distance, background noise, and poor room acoustics. ALDs are used at home, work and in school to help improve listening ability and reduce stress and fatigue in many day-to-day communication situations.

Types of Assistive Listening Devices
Personal FM Systems
A personal FM system consists of a transmitter microphone used by the speaker and a receiver used by the listener. The receiver transmits the sound to your hearing aid, or headset if you don’t wear a hearing aid, through the use of a special frequency assigned by the Federal Communications Commission, much like a miniature radio station. Personal FM systems are used in a variety of situations such as classrooms, restaurants, theaters, places of worship, museums, public meeting places and convention centers.

Infrared Systems
Usually used in the home with TV sets or large settings like theaters. Sounds is transmitted using infrared light waves. The infrared system transmits the TV signal to a headset, which can be adjusted to the listeners desired volume setting. This allows others to watch the program at a normal volume setting, while the Infrared user can adjust the volume to his listening needs.

Induction Loop Systems
An induction loop wire is permanently installed in a room and connected to a microphone system. The person talking into the microphone creates a current in the wire that makes an electromagnetic field in the room. When Hearing aids are switched to the “T” (telecoil/telephone) setting, it picked up the signal from the induction loop. The volume of the signal can be adjusted by adjusting the volume control on the hearing aid. These systems are commonly used in large group meeting areas.

Personal Amplification Devices
These are individual devices, which resemble “walkman” radios, and consist of a microphone, an amplifier and a headset or direct connect into a hearing aid. The speaker uses the microphone and the listener adjusted the amplifier volume to a desired level. These are often used in private settings or places like restaurants and cars.

Other Assistive Listening and Alerting Devices
There are many other devices which are used alone or in conjunction with hearing aids to assist and alert the hard of hearing or deaf. These devices include:

Amplified telephones, answering machines, paging systems, computers and alarm clocks Vibrotactile and visual alerting systems to alert people when a sound occurs. Examples include, when a doorbell rings, phone rings, fire/smoke alarms sound, alarm clock sounds and when a baby cries Text telephones that allow phone conversations to be typed and read Computerized speech recognition that changes a spoken message into a typewritten document Closed caption TV that displays spoken dialogue as text The audiologists at St. John Hospital and Medical Center are equipped to provide a complete range of audiologic and vestibular testing and rehabilitative services, including hearing aid selection and dispensing.

Appointments can be scheduled by contacting the Audiology department 313-343-3165. You can also contact audiologists at St. John Hospital via e-mail at

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