The Development of Lateralization Abilities in Children with Bilateral Cochlear Implants

Objectives: The purpose of this study was to investigate the
developmentof lateralization skills in children who received
bilateral cochlearimplants (CIs) in sequential operations. Methods:
The lateralizationskills of 9 children with a mean age of 4.1 years
at the first surgeryand 5.5 years at the second surgery were
assessed at 3 time intervals.Children were assessed with a
3-loudspeaker setup (front, left andright) at 0.9 years (interval
I) and 1.6 years (interval II) after thesecond implantation, and
after 5.3 years of bilateral implant use(interval III) with a
9-loudspeaker setup in the frontal horizontalplane between -90
degrees and 90 degrees azimuth. Results: Withbilateral implants, a
significant decrease in lateralization error wasnoted between test
interval I (45.0 degrees) and 11 (23.3 degrees), witha subsequent
significant decrease at test interval III (4.7 degrees).Unilateral
performance with the CI did not improve significantly betweenthe
first 2 intervals; however, there was a bias of responses
towardsthe unilateral side by test interval III. Conclusions:
Thelateralization abilities of children with bilateral CIs develop
in arelatively short period of time (1-2 years) after the second
implant.Children appear to be able to acquire binaural skills after
bilateralcochlear implantation.