FM Systems with Children who are Deaf-Blind

Key Words: Deaf Education Information, Technologies for Deaf/HH

The focus of this four-year research to practice project is the contribution of FM systems to the development of communication skills in infants, toddlers, children, and youth who are deaf-blind. Classrooms and other public areas such as auditoriums, theaters, and restaurants provide a poor acoustical environment for individuals who have a hearing loss, and it is often difficult for them to discriminate between the speaker and background noise with a hearing aid. The three environmental factors that account for a decrease in listening ability are:

  1. Distance- Since sound decreases as distance increases, speech discrimination also decreases as the distance between the speaker and listener increases.
  2. Background Noise- It is harder to hear as the speech to noise ratio increases.
  3. Room Acoustics- When sound bounces off a surface it causes an echo and the resulting reverberation can mask speech.

    The use of an Assistive Learning Device can significantly reduce the distance, reverberation, and acoustic problems by providing a constant sound pressure level of the speaker's voice. The two most typical types of Assistive Listening Devices are personal FM systems where the sound is sent through the hearing aid(s) and FM Auditory Trainers which are independent amplification systems. With a personal FM system, the speaker wears a microphone transmitter and his/her voice is sent to a receiver which is attached to the microphone of the listener's hearing aid(s) in one of two ways: 1) by direct audio input coupling using a boot attachment with the hearing aid(s), or 2) by inductive coupling using a Teleloop worn around the neck. With an Fm Auditory Trainer, the speaker also wears a microphone transmitter and his/her voice is sent to a microphone in the receiver that is contained within the device. In this way, the Auditory Trainer itself functions as a body-worn hearing aid. However, in both of these situations, the listener must wear a rather cumbersome receiver on the body.

    A number of personal FM systems have two volume controls on the receiver- one controlling FM reception ( speaker) and the other controlling the environmental signal. With this set-up, the volume control on the environmental microphone can be adjusted so that the individual wearing the FM system can hear the speaker as well as themselves and others.

    The manufactures of these types of FM systems include:

    Phonic Ear

    A relatively new type of FM receiver is now available which combines the hearing aid and FM system in a single behind-the-ear unit (BTE/FM). This new BTE/FM system eliminates the body-worn case as well as all loops and cords for the listener. The unit can function as a hearing aid alone, an FM system alone, or a hearing aid and FM system at the same time. These FM systems were produced first by Phonic Ear which is called the "Free Ear" and by AVR Sonnovation in Israel which is called the "Extend Ear" comes in a variety of power and frequency combinations to cover a wide rage of hearing loss configurations, from mild to profound. Telex has just come out with its own FM/BTE unit called the "SELECT 2-40". All of these FM/BTE units have an antenna on the end. The devices are becoming more sophisticated in channel changeability- Sonnovation attaches a boot to the unit and Telex has two channels built into their system.

    FM Technology is continually expanding. There are two new developments which are just being introduced. The first is a "boot" attachment called the "UNICOM" developed by Unitron which will change one of their over-the-ear hearing aids--the US80-- into a FM/BTE. This is designed for individuals with a severe to profound hearing loss who need to communicate in noisy environments. This product is the result of a joint effort by Unitron and Sonnovation.

    The latest FM technological advance comes from Phonak and is called the "MICROLINK". The company has developed the world's smallest FM microchip ever designed for spoken communication and they consider it to be a revolution in hearing instrument technology. The "Microlink" is about 1/3 of an inch and is attached to a plastic boot which slips over the end of the over-the -ear hearing aid. Another advantage of the "Microlink" is that the antenna is built into the unit and does not stick out. This FM product has been designed to be compatible with the entire line of Phonak hearing aids, including their most sophisticated high-power digital aid.

    Although FM technology is expanding rapidly, it still is not as user friendly as one would hope. This project is currently in its third year of a four-year Research to Practice grant funded by the Office of Special Education Programs, Services for Children with Deaf-Blindness (84.025s). Training materials , including a Video and accompanying Manual, will be developed during the final year of the project. It is hoped that these materials will help make FM systems user friendly so that more children who are deaf-blind can profit from improvement in communication that can be accomplished through current and future FM technology.

    For additional information and yearly progress reports, please contact:

    Barbara Franklin, Ph.D.
    Department of Special Education
    San Francisco State University
    1600 Holloway Avenue
    San Francisco, CA 94132

    Uploaded By: Jodi Gray/KSU/Deaf Education Major