|Authors||Thakkar TD, Brown AD, Jones HG, Kan A, Litovsky RY|
|Journal||J. Acoust. Soc. Am. Volume: 135 Issue: 4 Pages: 2411|
|Publish Date||2014 Apr|
In reverberant environments, listeners rely on early arriving spatial cues to accurately localize sound sources, a phenomenon known as the precedence effect (PE). In deaf individuals fitted with bilateral cochlear implants (BiCIs), this effect is diminished, ostensibly due to the fact that clinical processers do not preserve binaural cues. We have recently demonstrated that BiCI listeners do exhibit aspects of the PE similar to normal-hearing (NH) listeners when binaural stimulation is restored using synchronized research devices. Here, we consider whether BiCI users also demonstrate an aspect of the PE known as “buildup”-enhancement of the PE after a repeated stimulus. BiCI users with demonstrated sensitivity to interaural time differences (ITDs) were tested using dichotic electrical pulses (±500µs ITD in opposing “lead” and “lag” pulse pairs, with lead-lag delays of 1-64 ms). On each trial, listeners indicated (1) whether one or two locations were perceived (to assess “fusion”) and (2) the location perceived (or, given two locations, the “left-most” location perceived, to assess “localization dominance”). Preliminary results indicate that ‘buildup’ may be atypical in BiCI users, who have experienced years of acoustic deprivation. Lack of adaptation to redundant stimuli may temper the extent of benefit from restored binaural inputs in reverberant environments.