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. ALDs improve speech to noise ratio increasing the level of understanding for people who have problems distinguishing speech in noise to the same level as people with normal hearing ability.
They use a microphone, transmission technology, and a device for receiving the signal and bringing sound to the ear. The types of ALDs include telephone, FM, infrared and inductive loop. With the exception of telephone amplifiers, ALDs broadcast sound wirelessly.
ALDs are basically personal amplifiers that separate speech from background noises and boost the volume of sound entering the ears. They help increase the effectiveness of hearing aids and cochlear implants by overcoming distracting background sounds and minimizing the effects of distance and poor acoustics. ALDs are similar to FM systems, but might use infrared or inductive loop technologies in addition to radio signals. They are useful in classrooms, churches, movie theaters and at home.
FM (Frequency Modulated) systems consist of a transmitter, microphone and receiver. They are used to improve hearing in situations where background noise, distance or reverberation are factors. The microphone and transmitter are worn by or placed in close proximity to the speaker, and the listener wears the receiver. The transmitter sends a radio signal to the receiver, which forwards it to the hearing aid, cochlear implant or other device. FM systems are useful in classroom settings and around the home.
As with any hearing aid accessory, a hearing professional can help you decide which ALD is right for you. If you would like to discuss ALDs with an audiologist, please contact our office at 717-728-9700.