The effect of presentation level and stimulation rate on speech perception and modulation detection for cochlear implant users.
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Date
2017-06
Journal Title
Journal ISSN
Volume Title
Publisher
Acoustical Society of America
Abstract
In order to improve speech understanding for cochlear implant users, it is important to maximize the transmission of temporal information. The combined effects of stimulation rate and presentation level on temporal information transfer and speech understanding remain unclear. The present study systematically varied presentation level (60, 50, and 40 dBA) and stimulation rate [500 and 2400 pulses per second per electrode (pps)] in order to observe how the effect of rate on speech understanding changes for different presentation levels. Speech recognition in quiet and noise, and acoustic amplitude modulation detection thresholds (AMDTs) were measured with acoustic stimuli presented to speech processors via direct audio input (DAI). With the 500 pps processor, results showed significantly better performance for consonant-vowel nucleus-consonant words in quiet, and a reduced effect of noise on sentence recognition. However, no rate or level effect was found for AMDTs, perhaps partly because of amplitude compression in the sound processor. AMDTs were found to be strongly correlated with the effect of noise on sentence perception at low levels. These results indicate that AMDTs, at least when measured with the CP910 Freedom speech processor via DAI, explain between-subject variance of speech understanding, but do not explain within-subject variance for different rates and levels.
Description
Keywords
Cochlear implant
Citation
Brochier, T., H. J. McDermott, and C. M. McKay. 2017. The effect of presentation level and stimulation rate on speech perception and modulation detection for cochlear implant users. The Journal of the Acoustical Society of America. 141(6): 4097.