title: Using the observer-based psychophysical procedure to assess localization acuity in toddlers who use bilateral cochlear implants.
abstract: OBJECTIVE
  Localization acuity will emerge in deaf children who receive bilateral cochlear implants (BI-CIs) before the age of 3 years but not in age-matched children who use a single device.
  
  
  BACKGROUND
  There is a growing clinical trend in which infants with severe-to-profound sensorineural hearing loss are receiving BI-CIs by 3 years. Although there is general agreement that better communicative and educational outcomes are achieved when the first implant is provided at a young age, there are few behavioral data showing the functional benefits of providing infants with BI-CIs. One potential benefit of BI-CIs is improved localization acuity, which develops within the first few years of life.
  
  
  METHODS
  Two groups of children with chronological ages ranging from 26 to 36 months participated: 1) children with normal hearing (n = 8) and 2) children with severe-to-profound sensorineural hearing loss (n = 18). Of the children who are deaf, 10 used BI-CIs, and 8 used unilateral cochlear implants. Localization acuity was measured with a single interval 2-alternative-forced choice right/left discrimination task, and minimum audible angles were computed at a performance level of 80% correct. Behavioral data were collected using the observer-based psychophysical procedure.
  
  
  RESULTS
  Preliminary results show that the observer-based psychophysical procedure is a feasible method to measure localization acuity in children with normal hearing and in deaf children with cochlear implants and that localization acuity is emerging in toddlers with BI-CIs but not yet in toddlers with unilateral cochlear implants.
  
  
  CONCLUSIONS
  These data are among the first to show localization acuity in young children who use BI-CIs.
authors.affiliation: Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA. grieco@waisman.wisc.edu
authors.forename: Tina M
authors.initials: TM
authors.lastname: Grieco-Calub
authors.forename: Ruth Y
authors.initials: RY
authors.lastname: Litovsky
authors.forename: Lynne A
authors.initials: LA
authors.lastname: Werner
mesh_terms: D002675:Child, Preschool; D003054:Cochlear Implants; D003627:Data Interpretation, Statistical; D004192:Discrimination, Psychological / Q000502:physiology; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006319:Hearing Loss, Sensorineural / Q000235:genetics / Q000523:psychology / Q000628:therapy; D006801:Humans; D007223:Infant; D008297:Male; D011601:Psychophysics; D013017:Sound Localization / Q000502:physiology*