title: Age sensitivity in the acquisition of lexical tone production: evidence from children with profound congenital hearing impairment after cochlear implantation.
abstract: OBJECTIVE
  This study investigated the effects of implant experience and age at implantation on the Cantonese tone production of children with cochlear implants. The study also examined whether there was a particular age at which children were more responsive to acquiring tones.
  
  
  METHODS
  The study included 45 children who had received unilateral cochlear implants at a mean age of 65.56 months. The subjects were grouped according to their age at cochlear implantation and were assessed annually for 5 years thereafter. A picture-naming task was used to measure their tone production performance.
  
  
  RESULTS
  A simple effect of age at implantation was significant at all testing intervals except at the preoperative data point. Children who were younger than 4 years of age when they received their implants scored significantly higher than did the 2 older groups at various testing intervals. A significant simple effect of implant experience was also found. Progress was most striking in children who received their implants before the age of 4 years.
  
  
  CONCLUSIONS
  For the most effective acquisition of Cantonese lexical tones, children should undergo early cochlear implantation. For children who receive implants before the age of 4 years, benefits are noted in tone production ability in terms of a faster rate of improvement within a shorter period of time.
authors.affiliation: Institute of Human Communicative Research, Department of Otorhinolaryngology-Head and Neck Surgery, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Kathy Y S
authors.initials: KY
authors.lastname: Lee
authors.forename: Charles Andrew
authors.initials: CA
authors.lastname: van Hasselt
authors.forename: Michael C F
authors.initials: MC
authors.lastname: Tong
mesh_terms: D000293:Adolescent; D000367:Age Factors; D002648:Child; D002675:Child, Preschool; D003054:Cochlear Implants; D005260:Female; D034381:Hearing Loss / Q000151:congenital* / Q000628:therapy*; D006801:Humans; D007223:Infant; D007804:Language Development; D008297:Male; D010898:Pitch Perception