title: A longitudinal study of the bilateral benefit in children with bilateral cochlear implants.
abstract: OBJECTIVE
  To study the development of the bilateral benefit in children using bilateral cochlear implants by measurements of speech recognition and sound localization.
  
  
  METHODS
  Bilateral and unilateral speech recognition in quiet, in multi-source noise, and horizontal sound localization was measured at three occasions during a two-year period, without controlling for age or implant experience. Longitudinal and cross-sectional analyses were performed. Results were compared to cross-sectional data from children with normal hearing.
  
  
  METHODS
  Seventy-eight children aged 5.1-11.9 years, with a mean bilateral cochlear implant experience of 3.3 years and a mean age of 7.8 years, at inclusion in the study. Thirty children with normal hearing aged 4.8-9.0 years provided normative data.
  
  
  RESULTS
  For children with cochlear implants, bilateral and unilateral speech recognition in quiet was comparable whereas a bilateral benefit for speech recognition in noise and sound localization was found at all three test occasions. Absolute performance was lower than in children with normal hearing. Early bilateral implantation facilitated sound localization.
  
  
  CONCLUSIONS
  A bilateral benefit for speech recognition in noise and sound localization continues to exist over time for children with bilateral cochlear implants, but no relative improvement is found after three years of bilateral cochlear implant experience.
authors.affiliation: * Department of Clinical Science, Intervention and Technology, Karolinska Institutet , Stockholm , Sweden.
authors.forename: Filip
authors.initials: F
authors.lastname: Asp
authors.forename: Elina
authors.initials: E
authors.lastname: Mäki-Torkko
authors.forename: Eva
authors.initials: E
authors.lastname: Karltorp
authors.forename: Henrik
authors.initials: H
authors.lastname: Harder
authors.forename: Leif
authors.initials: L
authors.lastname: Hergils
authors.forename: Gunnar
authors.initials: G
authors.lastname: Eskilsson
authors.forename: Stefan
authors.initials: S
authors.lastname: Stenfelt
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D003054:Cochlear Implants; D003430:Cross-Sectional Studies; D003638:Deafness / Q000601:surgery / Q000628:therapy*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009622:Noise; D059629:Signal-To-Noise Ratio; D013017:Sound Localization; D013067:Speech Perception; D013069:Speech Reception Threshold Test
keywords: Bilateral cochlear implants; children; release from masking; sound localization