Localization and speech understanding by a patient with bilateral cochlear implants and bilateral hearing preservation

OBJECTIVES:: The authors describe the localization and speech-understanding abilities of a patient fit with bilateral cochlear implants (CIs) for whom acoustic low-frequency hearing was preserved in both cochleae. DESIGN:: Three signals were used in the localization experiments: low-pass, high-pass, and wideband noise. Speech understanding was assessed with the AzBio sentences presented in noise. RESULTS:: Localization accuracy was best in the aided, bilateral acoustic hearing condition, and was poorer in both the bilateral CI condition and when the bilateral CIs were used in addition to bilateral low-frequency hearing. Speech understanding was best when low-frequency acoustic hearing was combined with at least one CI. CONCLUSIONS:: The authors found that (1) for sound source localization in patients with bilateral CIs and bilateral hearing preservation, interaural level difference cues may dominate interaural time difference cues and (2) hearing-preservation surgery can be of benefit to patients fit with bilateral CIs.