Pitch contour identification with combined place and temporal cues using cochlear implants

Abstract

This study investigated the integration of place-and temporal-pitch cues in pitch contour identification (PCI), in which cochlear implant (CI) users were asked to judge the overall pitch-change direction of stimuli. Falling and rising pitch contours were created either by continuously steering current between adjacent electrodes (place pitch), by continuously changing amplitude modulation (AM) frequency (temporal pitch), or both. The percentage of rising responses was recorded as a function of current steering or AM frequency change, with single or combined pitch cues. A significant correlation was found between subjects' sensitivity to current steering and AM frequency change. The integration of place-and temporal-pitch cues was most effective when the two cues were similarly discriminable in isolation. Adding the other (place or temporal) pitch cues shifted the temporal-or place-pitch psychometric functions horizontally without changing the slopes. PCI was significantly better with consistent place-and temporal-pitch cues than with inconsistent cues. PCI with single cues and integration of pitch cues were similar on different electrodes. The results suggest that CI users effectively integrate place-and temporal-pitch cues in relative pitch perception tasks. Current steering and AM frequency change should be coordinated to better transmit dynamic pitch information to CI users.

Perceptual changes in place of stimulation with long cochlear implant electrode arrays

“…Another potential explanation is that the peak of stimulation from the most apical two or three electrodes are at the same location (from the same SG cell bodies) but the spread of excitation from the most apical electrode would reach less basally than the second-most apical electrode. Using multi-dimensional scaling (MDS), Tong et al (1983) showed that a change in rate of stimulation and a change in place of stimulation represent different perceptual dimensions, even though subjects describe changes in rate, place, or a combination of the two as a change in pitch (e.g., Luo et al, 2012). Therefore, if the perceptual changes in the apex are not changes in place pitch, a pitch related task (such as pitch scaling, ranking, or matching) may not adequately describe the perceptual attributes of the apex.…”

Qualities of Single Electrode Stimulation as a Function of Rate and Place of Stimulation with a Cochlear Implant

“…When both rate and place coding are changed in complementary or contradictory directions, the amount of perceived change in pitch is either increased or decreased accordingly (e.g. Zeng et al, 2002; Stohl et al, 2008; Luo et al, 2012). Nevertheless, although both changes in rate and place of stimulation affect pitch, the two are not interchangeable, but are instead perceptually orthogonal (e.g.…”

Interleaved Processors Improve Cochlear Implant Patients’ Spectral Resolution

“…The pitch can effectively be “steered” anywhere between the two component electrodes by adjusting the relative amplitudes of each of the component electrodes (e.g., Donaldson et al 2005; Firszt et al 2007). Steering virtual channels between two electrodes is perceived to cause a continuous change in pitch (Luo et al 2010; Luo et al 2012). Furthermore, the spread of excitation of a virtual channel is the same as the spread of excitation from one physical electrode (Busby et al 2008; Saoji et al 2009).…”