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Semin Hear 2005; 26(2): 87-98
DOI: 10.1055/s-2005-871008
Published in 2005 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA.

In-the-Ear Measurements of Interference in Hearing Aids from Digital Wireless Telephones

Harry Levitt1 , 2 , Linda Kozma-Spytek3 , 5 , Judith Harkins4 , 5
  • 1Professor Emeritus, The City University of New York
  • 2Director of Research, Advanced Hearing Concepts, Bodega Bay, California
  • 3Research Audiologist, Gallaudet University, Washington, DC
  • 4Professor, Gallaudet University, Washington, DC
  • 5Technology Access Program, Gallaudet University, Washington, DC
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Publication History

Publication Date:
24 May 2005 (online)

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ABSTRACT

Digital wireless telephones produce audible and often annoying interference in hearing aids. A standard, ANSI C.63.19, has been developed for measuring electromagnetic emissions from wireless telephone handsets as well as immunity in hearing aids. Based on the test results for a handset and a hearing aid, an estimated prediction of usability for that combination of devices can be made. One question that arose during the development of the standard was the acoustic signal-to-interference ratio (SIR) requirements for various levels of telephone usability as rated by hearing aid wearers. An experiment was conducted in which 42 hearing aid wearers listened to a telephone conversation through a dummy wireless phone while interference levels were 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% 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 Limitations on Use.

KEYWORDS

Electromagnetic interference - digital wireless telephones - hearing aids - usability ratings - speech-to-interference ratio

REFERENCES

2 It is likely that the revised standard will use slightly different symbols than those cited.

  • 1 European Hearing Instruments Manufacturers Association .GSM Project Final Report: Hearing Aids and GSM Mobile Telephones: Interference Problems, Methods of Measurement and Levels of Immunity. Technical-Audiological Laboratory and Telecom Denmark. Wemmel, Belgium: EHIMA 1995
    Google Scholar
  • 2 Le Strange J R, Byrne D, Joyner K H, Symons G L. Interference to Hearing Aids by the Digital Mobile Telephone System, Global System for Mobile Communications (GSM). NAL Report No. 131. Chatswood, New South Wales, Australia: National Acoustic Laboratories, Australian Hearing Services 1995
    Google Scholar
  • 3 Skopec M. Hearing aid electromagnetic interference from digital wireless phones.  IEEE Trans Rehabil Eng. 1998;  6 235-239
    CrossrefPubMedGoogle Scholar
  • 4 Ravindran A, Schlegel R E, Grant H. Evaluation of the Interaction between Wireless Phones and Hearing Aids, Phase I: Results of the Clinical Trials. EMC Report 1996-2. Norman, OK: Center for the Study of Wireless Electromagnetic Compatibility, University of Oklahoma 1996
    Google Scholar
  • 5 Schlegel R E, Fry T L, Grant H. Investigation of the Interaction between Wireless Phones and Hearing Aids, Phase III-B: Subjective Validation Study. EMC Report 1999. Norman, OK: Center for the Study of Wireless Electromagnetic Compatibility, University of Oklahoma 1999
    Google Scholar
  • 6 Srinivasan S, Schlegel R E, Grant H. Evaluation of the Interaction between Wireless Phones and Hearing Aids, Phase II-B: Clinical Determination of the Speech-to-Interference Ratio. EMC Report 1997-2. Norman, OK: Center for the Study of Wireless Electromagnetic Compatibility, University of Oklahoma 1998
    Google Scholar
  • 7 Levitt H, Harkins J, Singer B, Yeung E. Field measurements of electromagnetic interference in hearing aids.  J Am Acad Audiol. 2001;  12 275-280
    PubMedGoogle Scholar
  • 8 American National Standards Institute .American National Standard for Methods of Measurement of Compatibility between Wireless Communications Devices and Hearing Aids (ANSI/IEEE C63.19-2001). New York, NY; ANSI 2001
    Google Scholar
  • 9 Berger S. Hearing aid and cellular telephone compatibility: working toward solutions.  J Am Acad Audiol. 2001;  12 309-314
    PubMedGoogle Scholar
  • 10 Federal Communications Commission .Report and Order in the Matter of Section 68.4(a) of the Commission’s Rules Governing Hearing Aid-Compatible Telephones WT Docket No. 01-309, RM-8658; August 2003
  • 11 Burwood E. Assessment of Interference to Hearing Aids Used in Australia by CDMA Digital Mobile Phones, NAL Report-Phase 1, Reference EB831. Chatswood, New South Wales, Australia: National Acoustic Laboratories, Australian Hearing Services 1999
  • 12 Killion M. Digital Cellphone Progress Report. Paper presented at: Hearing Industry Association Annual Meeting; February 24, 2000; Palm Springs, CA. Cited by Preves D. Hearing aids and digital wireless telephones.  Semin Hear. 2003;  24 43-62
    Article in Thieme ConnectPubMedGoogle Scholar

Harry LevittPh.D. 

Advanced Hearing Concepts, Director of Research

998 Sea Eagle Loop, P.O. Box 1166, Bodega Bay, CA 94923-1166

Email: harrylevitt@earthlink.net