In-The-Ear Measurements of Interference in Hearing Aids from Digital Wireless Telephones
By Levitt, Harry, PhD; Kozma-Spytek, Linda, MA; Harkins, Judith, PhD; Seminars in Hearing, Vol. 26, No. 2, pp. 87-98Publication Date: 2005
Study identified the acoustic signal-to-interference ratio (SIR) requirements for various levels of digital wireless telephone usability for people who wear hearing aids. Digital wireless telephones produce audible electromagnetic interference in hearing aids. Forty-two hearing aid wearers listened to a telephone conversation through a dummy wireless phone while interference levels varied using a second phone programmed to deliver a controlled electromagnetic field. Real-ear recordings of the speech with interference were made at each rating point of usability. Signal analyses of the recordings indicate that for 90 percent of the subjects, SIRs in the 28- to 32-dB range were needed to achieve a rating of highly usable, SIRs in the 20- to 24-dB range were needed for a rating of minor limitations on use, and SIRs in the 12-to 15-dB range were needed for a rating of major limitation on use.
Published by: Thieme Medical Publishers, Inc. (Website:http://www.thieme.com)
American Speech-Language-Hearing Association (Web Site: http://www.asha.org )
