Study of the Interaction of
Wireless Phones and Hearing Aids

[Order Report]         [Executive Summary]

The Center for the Study of Wireless Electromagnetic Compatibility at the University of Oklahoma began its initial examination of the interaction issues between wireless phones and hearing aids in May 1995. The first phase of the Hearing Aid Clinical Study was conducted in cooperation with the Hough Ear Institute in Oklahoma City, Oklahoma.

Phase I results were presented on April 29, 1996 to representatives of hearing aid user groups, wireless service providers and manufacturers, hearing aid manufacturers, and the Federal Communications Commission (FCC).

At the time of its completion, this clinical study was the most comprehensive scientific effort in the United States to involve a diverse group of hearing aid users to determine the degree of interaction between hearing aids and wireless phones.

Phase I Results

In September 1996, the Center published the full report of Phase I results of the clinical study examining the interaction between hearing aids and digital wireless phones.

This study identified several factors that contribute to interference between wireless phones and hearing aids, and determined the effectiveness of some proposed solutions to mitigate or minimize the extent of interference. It also demonstrated the complexity of the problem.

This data was viewed as "first phase" results and not necessarily typical of actual use. The degree of interaction varied depending on factors such as phone technology, hearing-aid type, hearing loss configuration and severity of hearing loss, or as a combination of these factors. The analog cellular phones tested did not interfere with any of the hearing aids.

Under the most extreme conditions, hearing aid users (on average) did not experience annoying interaction due to phone signals unless the phones were within 24 inches of the hearing aid. The threshold distance to detect any interaction (not necessarily annoying) was one meter (3.3 feet) between the hearing aid and the phone.

The Phase I clinical trials with 68 hearing aid users and 10 non-hearing aid users began in December 1995 and concluded at the end of March 1996.