When Hearing Aids Are Not Enough
The Need for Assistive Devices

Audiology - Diagnosis Audiology - Treatment Audiology - Management

Excerpts from Audiology Treatment provided by


with permission from Thieme Medical Publishers, Inc., New York, NY.

Michael Valente, Ph.D., Washington University School of Medicine, St. Louis, Missouri.
Holly Hosford-Dunn, Ph.D., Tucson Audiology Institute, Inc., Tucson, Arizona.
Ross J. Roeser, Ph.D., University of Texas at Dallas, Dallas, Texas.

Peter O. Bengtsson, Centrum Sound Systems, Redding, California.
Preben B. Brunved, Oticon Inc., Somerset, New Jersey.

Chapter 19

When Hearing Aids Are Not Enough
The Need for Assistive Devices

Search Centrum Sound's website


Page 1
Why Assistive Listening Devices?

Sound Pickup
Omnidirectional and Unidirectional Microphones
Microphone Designs for Assistive Listening Devices
Lapel/Handheld Microphones
Conference Microphones
Other Microphone Styles
Public Address Systems
Page 2
Signal Transfer Method
Hard wired Systems
Wireless Technologies

Induction Loop Systems (Teleloop)
The Concept of the Induction Loop
Electromagnetic Field Strength and Frequency Response of Room Loops
Loop Amplifiers
Installation Limitations and Considerations

Frequency Modulated Broadcast Systems (FM)
Frequency Modulation Technology
Wide-Band and Narrow-Band Frequencies
Narrow-Band Systems
Wide-Band Systems
Transmitter Types
FM Receiver Types

Infrared Light Systems (IR)
Infrared Technology
Transmitters and Emitters
Infrared Receivers
Page 3
Batteries and Charging Systems

Sound Couplings and Fitting Options
Direct Audio Input
Physical and Electrical Standardization of Direct Audio Input
The Direct Audio Input "Boot"
Attenuation of Direct Audio Input Cords and Boots
Direct Audio Input Sources and Connections
Control Settings of the Hearing Aid
Inductive Transfer of Signals
Limitations and Drawbacks with Inductive Transfer
Electromagnetic Compatibility
Induction Coil Sensitivity
External Hearing Aid Transducers, Headsets, and Earbuds


Preferred Practice Guide Lines


Centrum Sound Home