Horizontal-plane localization with bilateral cochlear implants using the SAM strategy
Sound source localization capability of cochlear implant (CI) users has been a popular research topic over the past few years, because it has both social and safety implications. While it is widely accepted that unilateral implantation does not provide enough information for this task, conditions, algorithms and their parameterization for the best performance in the binaural case are still in the focus of the research. On ISAAR 2009, we presented a simulation study revealing the theoretical limits of localization performance using the widespread ACE strategy. We also gave an example of how left-right speech processor asynchrony may influence the perceived direction. In the present paper we give an outline of a novel, auditory model based CI speech processing strategy called SAM. Furthermore, using the framework from the previous study, we show how localization performance increases when using SAM instead of ACE. We present detailed comparisons to show how factors like pulse rate, signal to noise ratio, reverberation, etc. affect horizontal-plane localization. Finally, we give a simple explanation, why, unlike other strategies, spatial perception with SAM is robust against device asynchrony.
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