Speech Perception, Dichotic Listening, and Ear Advantage in Simultaneous Bilateral Cochlear Implanted Children

OBJECTIVE: To study the development of dichotic listening, ear advantage, and speech perception in cochlear implant (CI) recipients using five audiometric tests. STUDY DESIGN: Prospective cohort analysis. SETTING: University Hospital. PATIENTS: One hundred twenty one participants who received simultaneous bilateral CIs and had at least 12 months of regular bilateral CI use. Age at time of testing ranged from 4 to 18 years with a mean age of 9 years (standard deviation [SD]: 3.0). Mean duration of CI use was 7.073 years (SD: 2.86). INTERVENTION: Bilateral simultaneous cochlear implantation. MAIN OUTCOME MEASURE: Goettinger and Freiburger monosyllabic word test, Hochmair, Schulz and Desoyer sentence (HSM) test in noise and in quiet conditions and the dichotic listening test by Uttenweiler were applied according to the childrens' age. The results were evaluated using a two-sided t test for dependent samples. RESULTS: In all tests applied, we could not show significant differences in performance between left and right CI and therefore could not demonstrate an ear advantage. Dichotic listening was challenging, only one subject produced results required for normal hearing subjects to pass the test. The older the CI recipients get and duration of CI use increases, the more results in all speech perception tests improve. CONCLUSIONS: Our results cannot lend further support to the existence of ear advantage in CI recipients. We do not recommend the Uttenweiler dichotic listening test to determine lateralization. Further research to gather more information on dichotic listening and ear advantage in CI recipients is necessary and should use consonant-vowel stimuli as more comparable stimuli.