We present sound localization results from 30 children with bilateral cochlear implants. All children received their implants sequentially, at ages from 6 months to 9 years for the first implant and 1.5–12 years for the second implant, with delays of 10 months to 9 years. Localization was measured in the sound field, with a broadband bell-ring presented from 1 of 9 loudspeakers positioned in the frontal horizontal plane. The majority of the children (63%) were able to localize this signal significantly better than chance level. Mean absolute error scores varied from 9 to 51° (root mean square error scores from 13 to 63°). The best scores were obtained by children who received their first implant before the age of 2 years and by children who used hearing aids prior to implantation for a period of 18 months or longer. Age at second implantation was important in the group of children who did not use a contralateral hearing aid during the unilateral implant period. Additionally, children who attended a mainstream school had significantly better localization scores than children who attended a school for the deaf. No other child or implantation variables were related to localization performance. Data of parent questionnaires derived from the Speech, Spatial and Qualities of Hearing Scale were significantly correlated with localization performance. This study shows that the sound localization ability of children with bilateral cochlear implants varies across subjects, from near-normal to chance performance, and that stimulation early in life, acoustically or electrically, is important for the development of this capacity.

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In all, 65 responses were obtained from 12 different countries. All clinicians said they would advise a CI user to wear a contralateral HA if indicated. However, a significant number (45%) had either never fitted HAs before or had less than 1 year of experience. In general, there were no specific criteria for selecting candidates to fit with an HA. A strategy to balance the HA with the CI was not used as a standard practice for any of the adults and was used in only 12% of the children. Only half the respondents were aware of the bimodal literature. The majority of professionals (18/30) did not refit the HA after CI switch-on. However, if users complained of sound quality or loudness issues or had poor test results, a follow-up session was provided. The main benefit reported by recipients was improvement in overall sound quality.

The results of this study show that the modified procedures are suitable for testing children from the age of 4 to 5 yr. Furthermore, it seems that binaural hearing capacities of the 5-yr-olds are similar to those of adults. Several observations led to the hypothesis that the observed age differences between 4-yr-olds and older subjects on localization and BMLD or between those 4- to 9-yr old and adults on lateralization, were attributable to both a development in binaural hearing and to nonauditory factors, such as task comprehension, attention, and testing conditions. It is possible that the developmental process is more obvious and prolonged in other aspects of binaural hearing, which require more dynamic or more central processing.

Bilateral cochlear implantation offered advantages to all children in comparison with the first implant--even the children who received the second implant after the age of 6 years. Compared to the younger children, the older children needed a longer adjustment period to gain bilateral benefit. However, they obtained similar results after 2 years of bilateral implant use.