University of Groningen
Perception of amplitude modulation with single or multiple channels in cochlear
implant users
Galvin, John
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Publication date:
2016
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Citation for published version (APA):
Galvin, J. (2016). Perception of amplitude modulation with single or multiple channels in cochlear implant
users [Groningen]: University of Groningen
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1. Temporal envelope information (changes in amplitude over time) is important for cochlear implant
users’ speech perception. Amplitude modulation detection and discrimination are two measures of
temporal envelope perception.
2. Peak amplitude may contribute to cochlear implant users’ modulation detection, but envelope
information appears to be the dominant cue (from thesis).
3. For multi-channel stimulation, current levels on each electrode must often be reduced to maintain
loudness, relative to single-channel stimulation (“loudness summation”; from thesis).
4. The lower current levels needed to accommodate multi-channel loudness summation negatively
affects modulation detection, but appears to have little effect on modulation discrimination (from
thesis).
5. Temporal envelope information appears to be combined across multiple channels, rather than
attending to the channels with the best or worst representation (from thesis).
6. Channel interaction at the neural level appears to affect how temporal envelope information is
combined across channels (from thesis).
7. At low current levels, single-channel modulation discrimination is poor. Performance can be
improved by increasing the current level of the single channel, or by adding channels of similar
loudness. Different from modulation detection, modulation discrimination appears to depend more
on loudness than current level (from thesis).
8. For cochlear implant psychophysics, method of constant stimuli (rather adaptive procedures) may
offer better estimates of and insights to perceptual acuity across parameters, with arguably less
time and stress to the subject.
9. Channel interaction, the limiting factor of spectral resolution in cochlear implants, always depends
on time and space.
10. Low rates may reduce temporally induced channel interaction and maximize multi-channel spectral
resolution.