Factors limiting binaural benefit for single-sided deafness cochlear-implant listeners

Single-sided-deafness cochlear implants [SSD-CIs; one normal-hearing (NH) and one CI ear] provide speech-in-noise benefits based on head-shadow advantages. SSD-CIs can also produce binaural benefits, but only in certain situations. This study examined how poor across-ear integration might limit binaural benefit. Ten SSD-CI listeners were tested with different combinations of target and competing coordinate-response-measuresentences presented to each ear. When target and masking speech were presented to the NH ear, adding a copy of the masker to the CI ear improved speech-identification performance, demonstrating binaural benefit. When target and masking speech were presented to the CI ear, adding a copy of the masker to the NH ear interfered with speech-identification performance. In both cases, adding different masking speech in the contralateral ear (instead of a copy of the first masker) produced interference. The results suggest that SSD-CI users experience partial binaural integration—enough to facilitate binaural benefits when attending to the NH ear, but not enough to overcome the interference produced by the perception of additional competing voices when attending to the CI ear. [The views expressed in this abstract are those of the authors and do not necessarily reflect the official policy of the Department of Defense or U.S. Government.]