Quantifying Telecoil Performance in the Ear: Common Practices and a New Protocol

ABSTRACT

Recent survey data presented here indicate that audiologists exhibit no clear pattern of preferred evaluation practices for hearing aids equipped with telecoils. The great majority surveyed rely on informal patient judgments of sound quality rather than on formal probe-microphone or speech-recognition measures. Formal telecoil-fitting protocols are reviewed, but none has gained wide acceptance, perhaps due to the time and equipment demands they present. Protocols that use an induction loop input do not represent the true conditions of telephone use. Formal quantification of telecoil performance in the patient's ear in response to a telephone input is thought to be an important factor in achieving a successful outcome. Modern hearing aids with amplified, programmable telecoils offer the means for increasing telecoil success, but that success depends on optimizing telecoil performance using a standard set of tools that can be applied quickly and consistently in the office. This article presents a practical seven-step protocol for optimizing telecoil performance that includes hearing aid requirements, suggested procedures, and a new, standard inductive signal source to present a known speech or noise signal to the hearing aid during programming of the telecoil memory.

KEYWORDS

Telecoil - quantification - Tel-Phone

REFERENCES

• 1 Teder H. Quantification of telecoil performance in the coupler.  Semin Hear . 2002;  24 63-70
• 2 American National Standards Institute. Specification of hearing aid characteristics, ANSI S3.22-1996 New York: Acoustical Society of America 1996
• 3 Mormer E, Mack A. Telephones throughout the lifespan.  Semin Hear . 2002;  24 1-16
• 4 Hawkins D, Beck L, Bratt G, Fabry D, Mueller H, Stelmachowicz P. The Vanderbilt/Department of Veterans Affairs 1990 Conference Consensus Statement: Recommended components of a hearing aid selection procedure for adults.  Audiology Today . 1991;  3 16-18
• 5 Wallber M J, MacKenzie D J, Clymer E W. Telecoil evaluation procedure. National Technical Institute for the Deaf, RIT, New York, by agreement with the U.S. Department of Education. Auditec of St. Louis; 1987 . 
• 6 Mueller H G, Bryant M P. Some commonly overlooked uses of probe microphone measures.  Semin Hear . 1991;  12 73-92
• 7 Grimes A M, Mueller H G. Using probe-microphone measures to assess telecoils and ALDs. Part I: Assessment of telecoil performance.  Hearing Journal . 1991;  44 16-21
• 8 Grimes A M, Mueller H G. Using probe-microphone measures to assess telecoils and ALDs. Part II: Assessment of ALD's, telephones and telephone amplifiers.  Hearing Journal . 1991;  44 21-29
• 9 Beck L B, Nance G C. Hearing aids, assistive listening devices, and telephones: issues to consider.  Semin Hear . 1989;  10 78-89
• 10 Compton C. Providing effective telecoil performance with in-the-ear hearing instruments.  Hearing Journal . 1994;  47 23-33
• 11 Yanz J L, Preves D A. Telecoil technology: principles, pitfalls, fixes and the future.  Semin Hear . 2002;  24 29-41
• 12 Revit L. Proper use of telecoils: it's as easy as 1, 2, 3 . . . 4! http://www.frye.com/library/application/ larry.html, April 14, 2002
• 13 Davidson S A, Noe C M. Programmable telecoil responses: potential advantages for assistive listening device fittings.  Am J Audiol . 1994;  3 59-64
• 14 Rodriguez G P, Holmes A E, DiSarno N J, Kaplan H. Preferred hearing aid response characteristics under acoustic and telecoil coupling conditions.  Am J Audiol . 1993;  2 55-59
• 15 Rodriguez G P, Holmes A E, Gerhardt K J. Microphone versus telecoil performance characteristics.  Hear Instr . 1985;  36 17-57
• 16 Preves D A. Standardizing hearing aid measurement parameters and electroacoustic performance tests. In: Valente M, ed. Hearing Aids: Standards, Options and Limitations New York: Thieme 1996: 1-71
• 17 The Tel-Phone Telephone Induction System, Pehratek Products, Inc., Minneapolis,MN 2002 . 
• 18 Stoker R G. An audiometer telephone interface.  Hear Instr . 1982;  6 28-46
• 19 Stoker R G. Telecommunications technology and the hearing impaired: recent research trends and a look into the future.  Volta Rev . 1982;  84 147-155
• 20 Kozma-Spytek L. Hearing aid compatible telephones: history and current status.  Semin Hear . 2002;  24 17-28
• 21 Preves D. Hearing aids and digital wireless telephones.  Semin Hear . 2002;  24 43-62