Assistive Listening Knowledge Base
  • Peer-reviewed study (single-blinded randomized crossover trial)

Difference in Speech Recognition between a Default and Programmed Telecoil Program

From https://assistivelisteningknowledgebase.org/evidence/ledda-2019/ · record checked 13 October 2026

  • Ledda KT, Valente M, Oeding K, Kallogjeri D
  • Journal of the American Academy of Audiology 30(6):502-515 (Thieme)

Independent (Division of Adult Audiology, Washington University School of Medicine in St. Louis; no conflict of interest declared; Widex USA provided the hearing aids and Oaktree Products the telephone amplifier for use in the study)

Summary

A trial comparing speech understanding through a hearing aid's default telecoil programme with the same telecoil programmed to match the fitted microphone response.

Key findings

  • Twenty experienced adult hearing aid users with slight to severe loss listened by telephone through one receiver-in-the-canal model (Widex Unique 440 Fusion), whose microphone programme had been fitted to NAL-NL1 by real-ear measurement. One telecoil programme stayed at the maker's default; the other was adjusted in a 2-cc coupler until its response matched the microphone's, aiming for an RSETS of 0 dB.
  • The default telecoil's RSETS (its high-frequency average relative to the microphone) averaged -3.6 dB (SD 2.6) and was negative, from -2 to -8 dB, in 19 of the 20 aids; the programmed telecoil averaged 0.1 dB. The default response had a similar shape but was 0.4 to 5.8 dB lower from 200 to 800 Hz.
  • Median sentence scores rose from 86.7% with the default telecoil to 92.8% with the programmed one, CNC word scores from 52% to 68% and phoneme scores from 74.6% to 84.7%; each difference was significant (p < 0.001).
  • The authors state that there is no best practice for programming the telecoil. They recommend dispensing hearing aids with a telecoil that is activated at the fitting, programming it in the coupler after fitting the microphone to target, and demonstrating it for telephone and loop listening, which they note needs manual rather than automatic activation.
  • Cites Delaware's 2016 law requiring audiologists to tell patients about telecoils, which the authors say was passed because citizens reported frustration at the lack of telecoil counselling.

Limits

Telephone listening only, through one handset held in place by a headband; loops were not tested. One hearing aid model from one maker, which the authors note limits the findings because each maker sets its default telecoil differently. Behind-the-ear style only. Published online on 25 September 2018. Full publisher text was checked through a Wayback Machine capture dated 27 February 2024; the live page required JavaScript. The Discussion and Figure 6 support the RSETS and low-frequency figures, and the Acknowledgments identify the equipment providers.

Read the original

www.thieme-connect.com/products/ejournals/html/10.3766/jaaa.17128

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Cited in

Cite this source

Ledda KT, Valente M, Oeding K, Kallogjeri D. Difference in Speech Recognition between a Default and Programmed Telecoil Program. Journal of the American Academy of Audiology 30(6):502-515 (Thieme). June 2019. https://www.thieme-connect.com/products/ejournals/html/10.3766/jaaa.17128 (accessed 13 October 2026).

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