Evidence for a right cochlear implant advantage in simultaneous bilateral cochlear implantation

Objectives/Hypothesis To compare speech perception performance with right versus left cochlear implants (CIs) in children with bilateral CIs implanted simultaneously. Study Design Prospective case series of patients undergoing simultaneous bilateral cochlear implantation. Methods Speech perception performance was tested in 10, right-handed children who received bilateral CIs simultaneously between 11 and 36 months (mean, 21 months), had at least 18 months of bilateral CI use, and were 5.3 years of age during testing. All children exhibited bilateral symmetrical severe-to-profound hearing loss prior to implantation and did not benefit from hearing aids. Speech perception performance was evaluated with the right CI and the left CI by means of an open-set monosyllabic word test in quiet presented at 45 dB HL in a sound field. Results All children exhibited higher performance with the right CI compared to the left CI. Group mean performance with the right CI was 66.5% compared to 52% with the left CI (P=.002), yielding a 14.5% difference. With increasing duration of bilateral CI use and age at evaluation, the right-left difference increased (r=0.72, P=.019 and r=0.74, P=.014, respectively). Conclusions Current preliminary data indicate that children with bilateral CIs implanted simultaneously exhibit a significant right ear advantage for speech. Similarly to reports on normal-hearing children, right ear preference for speech increased with increasing age and auditory-linguistic experience. Thus, simultaneous bilateral cochlear implantation may lead to normal development of auditory pathways and may be an important contributor to the superior auditory, language, and communication skills reported in children with bilateral versus unilateral CIs.