Criteria for Selecting an Optimal Device for the Contralateral Ear of Children with a Unilateral Cochlear Implant

Abstract

Objective: To identify clinical criteria for selecting the aiding device for the contralateral ear of children with a unilateral cochlear implant (CI). Methods: Sixty-five children, including 36 bilateral CI users and 29 bimodal users, participated in the study. A speech perception test (monosyllabic word test) in noise was administered. The target speech (65 dB sound pressure level) was presented from the front loudspeaker, and noise (10 dB signal-to-noise ratio) was presented from 3 directions: from in front of the child and 90° to the child's right and left sides. The test was performed using the first CI alone and under bilateral CI or bimodal conditions. The bilateral benefits to speech perception in noise were compared between bilateral CI users and bimodal users. Results: Significant benefits in speech perception in noise were evident in bilateral CI users in all 3 noise conditions. In bimodal users, the hearing threshold at low frequencies of ≤1 kHz in the nonimplanted ear affected the bilateral benefit. Bimodal users with a low-frequency hearing threshold ≤90 dB hearing level (HL) showed a significant bilateral benefit in various noise conditions. By contrast, bimodal users with a low-frequency hearing threshold >90 dB HL showed no significant bilateral benefits in all 3 noise conditions. Conclusions: Bilateral CI and bimodal listening provide better speech perception in noise than unilateral CI alone in children. The contralateral CI is better than bimodal listening for children with a low-frequency hearing threshold >90 dB HL. A hearing threshold at low frequencies of ≤1 kHz may be a good criterion for deciding on the type of device for the contralateral ear of children with a unilateral CI.

Bimodal Stimulation in Prelingually Deaf Children

“…A recent study on school-aged children reports that better speech recognition in noise can be observed in bimodal users, provided that the residual hearing pure-tone audiometry for frequencies 1 kHz is \90 dB HL. 15 As a consequence, the authors suggest first trying bimodal listening for children with a lowfrequency threshold 90 dB HL in the nonimplanted ear and then choosing a sequential CI only if there is no significant benefit in noise from the bimodal option. Similarly, and possibly for the same reasons, this study showed an inverse correlation between mean aided/unaided threshold and parental satisfaction with the HA performance.…”

“…A possible explanation of this discrepancy may be that after hearing restoration within the normal range by the CI, implanted children use their contralateral residual hearing to process the fine temporal structure of sounds, which is complementary to information provided by the CI. A recent study on school‐aged children reports that better speech recognition in noise can be observed in bimodal users, provided that the residual hearing pure‐tone audiometry for frequencies ≤1 kHz is <90 dB HL 15 . As a consequence, the authors suggest first trying bimodal listening for children with a low‐frequency threshold ≤90 dB HL in the nonimplanted ear and then choosing a sequential CI only if there is no significant benefit in noise from the bimodal option.…”