TY - JOUR
T1 - Recognition of temporally interrupted and spectrally degraded sentences with additional unprocessed low-frequency speech
AU - Başkent, Deniz
AU - Chatterjee, Monita
N1 - Funding Information:
This work was supported by Heinsus Houbolt Foundation and by a Rosalind Franklin Fellowship from the University of Groningen the second author was supported by the NIH/NIDCD Grant no. R01-DC004786 . The authors would like to thank Michal Stone for earlier comments on the design of the vocoder processor, Frits Leemhuis for help with experimental set-up, Nico Leenstra with evaluation of the participant responses, Joost Festen and Wouter Dreschler for help with the speech stimuli, William S. Woods and Hari Natarajan for help with the Articulation Index software, and the participants for all their efforts.
PY - 2010
Y1 - 2010
N2 - Recognition of periodically interrupted sentences (with an interruption rate of 1.5 Hz, 50% duty cycle) was investigated under conditions of spectral degradation, implemented with a noiseband vocoder, with and without additional unprocessed low-pass filtered speech (cutoff frequency 500 Hz). Intelligibility of interrupted speech decreased with increasing spectral degradation. For all spectral degradation conditions, however, adding the unprocessed low-pass filtered speech enhanced the intelligibility. The improvement at 4 and 8 channels was higher than the improvement at 16 and 32 channels: 19% and 8%, on average, respectively. The Articulation Index predicted an improvement of 0.09, in a scale from 0 to 1. Thus, the improvement at poorest spectral degradation conditions was larger than what would be expected from additional speech information. Therefore, the results implied that the fine temporal cues from the unprocessed low-frequency speech, such as the additional voice pitch cues, helped perceptual integration of temporally interrupted and spectrally degraded speech, especially when the spectral degradations were severe. Considering the vocoder processing as a cochlear implant simulation, where implant users' performance is closest to 4 and 8-channel vocoder performance, the results support additional benefit of low-frequency acoustic input in combined electric-acoustic stimulation for perception of temporally degraded speech.
AB - Recognition of periodically interrupted sentences (with an interruption rate of 1.5 Hz, 50% duty cycle) was investigated under conditions of spectral degradation, implemented with a noiseband vocoder, with and without additional unprocessed low-pass filtered speech (cutoff frequency 500 Hz). Intelligibility of interrupted speech decreased with increasing spectral degradation. For all spectral degradation conditions, however, adding the unprocessed low-pass filtered speech enhanced the intelligibility. The improvement at 4 and 8 channels was higher than the improvement at 16 and 32 channels: 19% and 8%, on average, respectively. The Articulation Index predicted an improvement of 0.09, in a scale from 0 to 1. Thus, the improvement at poorest spectral degradation conditions was larger than what would be expected from additional speech information. Therefore, the results implied that the fine temporal cues from the unprocessed low-frequency speech, such as the additional voice pitch cues, helped perceptual integration of temporally interrupted and spectrally degraded speech, especially when the spectral degradations were severe. Considering the vocoder processing as a cochlear implant simulation, where implant users' performance is closest to 4 and 8-channel vocoder performance, the results support additional benefit of low-frequency acoustic input in combined electric-acoustic stimulation for perception of temporally degraded speech.
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U2 - 10.1016/j.heares.2010.08.011
DO - 10.1016/j.heares.2010.08.011
M3 - Article
C2 - 20817081
AN - SCOPUS:78649841592
VL - 270
SP - 127
EP - 133
JO - Hearing Research
JF - Hearing Research
SN - 0378-5955
IS - 1-2
ER -