Pitch perception in cochlear-implant (CI) users has been described in the literature as severely limited. Using artificial tones, it was shown that the limited spectral resolution of the electrode–neuron interface implies “place cues,” which rely on the resolution of harmonics, are rarely accessible, and that, instead, pitch perception is primarily driven by so called “temporal cues.” These cues take the form of amplitude modulation of the stimulation pulse train of individual electrodes. However, in the case of speech, natural transients may render temporal cues less accessible, and place cues might be taking a larger role. To address this question, we prepared an odd-one-out task using triplets of syllables uttered by a female talker, where participants had to detect the interval where the f 0 had been lowered. Instead of only presenting these stimuli acoustically to the CI participants, we recorded the electrical output of individualized implant processors and altered the electrical stimulation patterns to suppress either temporal cues, place cues, or both. The obtained psychometric functions showed that most CI users primarily rely on temporal cues when present, but are still able to use place cues when the temporal cues have been removed. However some participants seemed to rely on both types of cues equally. Further investigation is required to determine factors explaining this variability amongst participants, and to confirm whether this pattern is also found in other types of natural sounds, like musical instruments.
Rotteveel et al. (Wed,) studied this question.