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  • Peer-reviewed study

The combined effects of reverberation and noise on speech intelligibility by cochlear implant listeners

From https://assistivelisteningknowledgebase.org/evidence/hazrati-loizou-2012/ · record checked 13 October 2026

  • Hazrati O, Loizou PC
  • International Journal of Audiology 51(6):437-443

Independent (University of Texas at Dallas; funded by the US National Institute on Deafness and Other Communication Disorders, grant R01 DC010494; the authors report no conflicts of interest)

Summary

Measured how reverberation, noise and both together reduce word recognition for adult cochlear implant users.

Key findings

  • Eleven adult implant users (Nucleus Freedom, ESPrit 3G and Nucleus 5) identified words in sentences fed through the auxiliary input of a research processor, in quiet, with reverberation (T60 of 0.6 and 0.8 s), with speech-shaped noise (+5 and +10 dB SNR), and with both.
  • Mean scores fell from 87% in anechoic quiet to 44% with a reverberation time of 0.6 s and 33% with 0.8 s.
  • Reverberation reduced intelligibility more than noise at the SNRs tested, and the two together more than either alone; even in the most favourable combined condition, mean scores did not exceed 50%.
  • The authors conclude that testing implant users in noise alone may underestimate the difficulties they meet in daily life, where reverberation and noise often coexist.
  • Methods, Simulated reverberant conditions, reports that the room impulse responses were recorded at a source-to-microphone distance of 5.5 m, beyond critical distance. The direct-to-reverberant ratios were −1.83 dB at 0.6 s and −3.00 dB at 0.8 s; this was a fixed-distance simulation, not a test across talker distances.

Limits

Simulated reverberation fed directly into a research processor, not real rooms or the users' own processors; eleven participants; no assistive listening system was tested, and the paper specifies the distance used to record the room responses but does not test different talker distances or discuss remote microphones.

Read the original

pmc.ncbi.nlm.nih.gov/articles/PMC3733354

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Cite this source

Hazrati O, Loizou PC. The combined effects of reverberation and noise on speech intelligibility by cochlear implant listeners. International Journal of Audiology 51(6):437-443. 22 February 2012. https://pmc.ncbi.nlm.nih.gov/articles/PMC3733354/ (accessed 13 October 2026).

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