There are a variety of technologies that assist individuals with hearing loss to participate in daily activities. Alerting devices use loud sounds or visual signals, such as a blinking light, to notify you that the doorbell or telephone is ringing or that an alarm is going off. Assistive listening devices, also called hearing assistive technology systems, or HATS, help reduce background noise and amplify the sounds you want to hear.
Personal frequency modulation, or FM, systems are like miniature radio stations operating on special frequencies. The personal FM system consists of a transmitter microphone used by the speaker and a receiver used by the listener. FM systems are often used in theaters, concert halls, places of worship, museums, public meeting places, corporate conference rooms, convention centers, and other large areas for gathering. In these situations, the transmitter is built into the overall sound system. You are provided with an FM receiver that can connect to your hearing aid or cochlear implant. The receiver can also connect to a headset if you don’t wear a hearing aid.
Infrared systems are often used in the home with TV sets, but, like FM systems, they can also be used in public settings. With an infrared system, sound from the TV is transmitted using infrared light waves. This sound is transmitted to your receiver, which you can adjust to your desired volume. The TV can be set to a volume comfortable for any other viewers with normal hearing.
Induction loop systems are most common in large group areas, but they can also be purchased for individual use. Induction loop systems work with hearing aids. An induction loop wire is permanently installed, typically under a carpet or in the ceiling, and connects to a microphone. The person talking into the microphone generates a current in the wire, which creates an electromagnetic field in the room. When you switch your hearing aid to the telecoil or telephone setting, your hearing aid telecoil picks up the electromagnetic signal. You can then adjust the volume of the signal through your hearing aid.
Personal amplifiers are useful in places where other systems are unavailable or when watching TV, being outdoors, or traveling in a car. About the size of a cell phone, these devices increase sound levels and reduce background noise for a listener. Some have directional microphones that can be angled toward the source of sound. As with other assistive listening devices, the amplified sound can be picked up by a receiver that the listener is wearing, either as a headset or as ear buds.