Author: Dolly Bhargava, M. Spec. Ed.


In writing this section I consulted with and appreciated the input (both information and images) from Andrew Willis, Assistive Technology Consultant from Word of Mouth Technology www.wom.com.au; Karina Badcock , Early Childhood Trained Teacher of the Deaf (oral deaf and Auslan user), and Margaret Haenke, Manager of Deafness Resources Australia:  www.deafnessresources.net.au

Lewis (1998) states that the three most common factors that affect the student’s ability to hear and understand in the classroom are background noise, reverberation and distance.  Hearing aids provide maximum benefit when the environment is relatively quiet, the acoustics are good and the student with hearing impairment is interacting at a close distance to the speaker (Turnbull, Turnbull, Shank and Smith, 2004).  However, in environments such as the classroom, difficulties with background noise, reverberation and distance cannot be solved by hearing aids alone.  An assistive listening device (ALD) may be beneficial.

Assistive listening devices (ALDs) are specifically designed to enhance sound by minimizing the negative effects of background noise, reverberation, and distance from the speaker and thereby maximizing the student’s ability to hear and understand.  ALDs are specifically designed to pick up the desired sound from as close to the sound source as possible and send it directly to the listener’s ear, which enhances hearing (Thurman, 1999).

There is a wide range of ALDs, from personal amplifiers and television listening devices to large area and stadium size systems (Thurman, 1999). In this section we will discuss three types of ALDs that are particularly useful for the classroom setting.  They include frequency modulated (FM systems), induction loops and sound field amplification systems.

Smith, Polloway, Patton and Dowdy (1998) outline some suggestions for teachers to assist students with hearing impairments on the use of the assistive listening devices to their maximum potential.  For example, teachers should:

  • Have sufficient knowledge about the type of ALD that the student uses.
  • Understand how the device works and have some ideas for troubleshooting commonly occurring problems.
  • Be able to determine whether the ALD is functioning properly or not.
  • Know how to take care of the ALD.
  • Know whom to contact if there is a problem with the ALD.

In the following sections we will discuss FM systems, induction loops and sound field amplification systems.