The advantages of sequential bilateral cochlear implantation were assessed in 29 children with a severe to profound hearing loss. The effect of age at second implantation and the effect of duration of bilateral implant use on the outcomes in speech perception and directional hearing were investigated. The children received their second cochlear implant at an age ranging from 2.8 to 8.5 years. Measurements were carried out preoperatively and postoperatively after 6, 12 and 24 months of bilateral implant use. A matched control group of 9 children with a unilateral implant were also measured over time and were compared with the study group after 12 and 24 months. Speech reception in both quiet and in noise and lateralization were measured. After 24 months, a minimum audible angle task was carried out. Bilateral advantages with regard to speech reception in quiet and in noise were already present after 6 months of bilateral implant use and improved thereafter. After 24 months, speech reception in noise had significantly improved with bilateral implants compared to that of children with a unilateral implant. The percentage of children that could accurately lateralize increased from 57% after 6 months to 83% after 24 months. With regard to the minimum audible angle task, loudspeakers were placed on average at ±42°. Age at second implantation did not have an influence on all outcomes. From the results it can be concluded that the advantages of bilateral hearing occur after sequential bilateral implantation and that age at second implantation does not influence the amount of bilateral advantage. Furthermore, it can be concluded that longer periods of bilateral implant use lead to greater bilateral advantages.

No abstract

Sequential bilateral cochlear implantation in children is associated with an improvement in QoL, although this is predominantly reflected in the disease-related aspects of QoL and not necessarily in generic QoL.

Effect sizes could not be pooled because of the heterogeneity of the studies. Therefore, we presented the results qualitatively. Although the level of evidence was low, the advantages of bilateral cochlear implants corresponded with the primary benefits of bilateral hearing, that is, improved speech perception in quiet and noise. Localization results were less consistent. No data on audiologic, speech production, or educational outcomes were available.

Pooling of data was not possible because of the heterogeneity of the studies. As in the NICE review, the level of evidence of the included studies was low, although some of the additional studies showed less risk of bias. All studies showed a significant bilateral benefit in localization over unilateral cochlear implantation. Bilateral cochlear implants were beneficial for speech perception in noise under certain conditions and several self-reported measures. Most speech perception in quiet outcomes did not show a bilateral benefit. The current review provides additional evidence in favor of bilateral cochlear implantation, even in complex listening situations.