Extent of lateralization at large interaural time differences in simulated electric hearing and bilateral cochlear implant users.
Level 4 - case-series / case-control
Cross-sectional comparative psychophysical study testing bilateral cochlear implant users and normal-hearing controls.
PubMed 28464641 · doi:10.1121/1.4979114
What was done
The study evaluated the perceived extent of lateralization elicited by controlled interaural time differences (ITDs) in bilateral cochlear implant (CI) users presented with single-electrode pulse-trains. These percepts were compared against normal-hearing (NH) listeners tested with broadband acoustic stimuli as well as acoustic simulations of CI hearing.
What was found
The abstract reports no exact numeric participant counts or quantitative lateralization ratings. Normal-hearing listeners perceived broadband stimuli as fully lateralized within the physiological range of ITDs. Conversely, for both real CI stimulation and CI simulations, natural ITDs covered only a fraction of the full lateralization range, requiring ITDs up to twice the natural limit to reach maximum lateralization.
Why it matters
Because standard physiological ITD cues fail to produce full lateralization in bilateral CI users, future binaurally linked CI sound processors may need artificial ITD-enhancement algorithms to optimize spatial hearing and sound localization.
Limits
The abstract omits key sample details, including sample size, CI device specifications, etiology/duration of deafness, and stimulation parameters (e.g., pulse rates, specific electrode pairs). It only tested single-electrode pulse trains, which do not capture complex multi-electrode acoustic environments.
Cited by
- supports The maximum interaural time difference for sound localization in humans is approximately half a millisecond.