Speech Intelligibility in Rooms with and without an Induction Loop for Hearing Aid Users

Summary

A loop-on versus loop-off test of sentence and nonsense-syllable intelligibility for 22 hearing aid users in a meeting room and a highly reverberant church, with a questionnaire on everyday listening.

Key findings

• Tested 22 hearing aid users with mild to profound losses, each wearing one hearing aid, and 10 normal-hearing listeners for reference, in the 48 m² meeting room of the Polish Association of the Deaf (reverberation time about 0.8 s) and in a church with plaster walls and a marble floor (about 5 s).
• Loops in both rooms were driven by Univox PLS-100 amplifiers and calibrated to IEC 60118-4:2006; without the loop, listeners heard the room's own sound system through their hearing aids' microphones.
• The loop significantly improved both sentence and logatome (nonsense-syllable) intelligibility in both rooms. Without it, intelligibility was very poor in the reverberant church; with it, sentence intelligibility did not depend on reverberation and reached about 95% for listeners with mild losses, with smaller but significant gains for greater losses.
• Results did not differ significantly between measurement points within each room, so they were averaged across seats.
• On a questionnaire adapted from the APHAB, the share of everyday listening problems reported fell by more than 62 percentage points on average with the loop, and answers varied less between listeners.

Limits

Two rooms, one loop amplifier model, and listeners using one hearing aid each, so the unaided ear also heard the room. The loop was compared with the hearing aid's own microphones listening to the room's sound system, not with other assistive systems. Most results are given only as figures. The paper gives the meeting room's reverberation time as about 0.8 s in its methods and about 1 s in its discussion. Field strength, background noise and frequency response at the seats are not reported. The publisher gives 27 January 2015 as the citation date; the issue went online on 2 April 2015.

Read the original

doi.org/10.1515/aoa-2015-0007

Link checked 9 October 2026. We link to the original and do not host copies.

Cited in

• What do listeners prefer, and how often do they use venue systems?Partly answered
• Where do hearing loops fall short: metal, spill, noise and upkeep?Partly answered
• What works in places of worship, and what do the rules ask of them?Partly answered
• How much do room acoustics and distance limit listening without a system, and what follows for choosing one?Partly answered
• How good is the sound each system delivers: bandwidth, codecs and speech understanding?Partly answered

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