Effect of the number of amplitude-compression channels and compression speed on speech recognition by listeners with mild to moderate sensorineural hearing loss.

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Salorio-Corbetto, Marina 
Baer, Thomas 
Stone, Michael A 
Moore, Brian CJ 

The use of a large number of amplitude-compression channels in hearing aids has potential advantages, such as the ability to compensate for variations in loudness recruitment across frequency and provide appropriate frequency-response shaping. However, sound quality and speech intelligibility could be adversely affected due to reduction of spectro-temporal contrast and distortion, especially when fast-acting compression is used. This study assessed the effect of the number of channels and compression speed on speech recognition when the multichannel processing was used solely to implement amplitude compression, and not for frequency-response shaping. Computer-simulated hearing aids were used. The frequency-dependent insertion gains for speech with a level of 65 dB sound pressure level were applied using a single filter before the signal was filtered into compression channels. Fast-acting (attack, 10 ms; release, 100 ms) or slow-acting (attack, 50 ms; release, 3000 ms) compression using 3, 6, 12, and 22 channels was applied subsequently. Using a sentence recognition task with speech in two- and eight-talker babble at three different signal-to-babble ratios (SBRs), 20 adults with sensorineural hearing loss were tested. The number of channels and compression speed had no significant effect on speech recognition, regardless of babble type or SBR.

Adult, Hearing Aids, Hearing Loss, Hearing Loss, Sensorineural, Humans, Speech Intelligibility, Speech Perception
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J Acoust Soc Am
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Acoustical Society of America (ASA)
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HB Allen Charitable Trust (unknown)
Medical Research Council (G8717539)
This work was supported by the H. B. Allen Trust and the Engineering and Physical Sciences Research Council (UK; Grant No. RG78536). M.A.S. was co-funded by the National Institute of Health Research Manchester Biomedical Research Centre and Trust Charitable funds of the Central Manchester University Hospitals National Health Service Foundation Trust.