Age Sensitivity in the Acquisition of Lexical Tone Production: Evidence from Children with Profound Congenital Hearing Impairment after Cochlear Implantation

Abstract

Objectives:

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.