Consonant Acquisition in Young Cochlear Implant Recipients and Their Typically Developing Peers

Abstract

Purpose: Consonant acquisition was examined in 13 young cochlear implant (CI) recipients and 11 typically developing (TD) children.

Method: A longitudinal research design was implemented to determine the rate and nature of consonant acquisition during the first 2 years of robust hearing experience. Twenty-minute adult-child (typically a parent) interactions were video and audio recorded at 3-month intervals following implantation until 24 months of robust hearing experience was achieved. TD children were similarly recorded between 6 and 24 months of age. Consonants that were produced twice within a 50-utterance sample were considered "established" within a child's consonant inventory.

Results: Although the groups showed similar trajectories, the CI group produced larger consonant inventories than the TD group at each interval except for 21 and 24 months. A majority of children with CIs also showed more rapid acquisition of consonants and more diverse consonant inventories than TD children.

Conclusions: These results suggest that early auditory deprivation does not significantly affect consonant acquisition for most CI recipients. Tracking early consonant development appears to be a useful way to assess the effectiveness of cochlear implantation in young recipients.

Figure 1.

Mean (and SD) of size of established consonant inventories as a function of group (cochlear implant [CI], typically developing [TD]) and months of robust hearing experience. Note that data collection began at 6 months of age for TD children.

Figure 2.

Customary and mastery use of specific consonants as a function of group (cochlear implant [CI], typically developing [TD]) and month of robust hearing experience. Note that data collection began at 6 months of age for TD children. The left edge of each horizontal bar represents customary use (50% of group), and the right edge represents mastery use (90% of group). If the bar ends without a point, this means that the phoneme was not mastered by the 24-month interval. In this case, the number next to the bar shows the percentage of children within the group that had established that consonant by the 24-month interval. Numbers in parentheses represent the percentage for TD children. *Consonants that at least one group of children had not mastered by the end of the study.

Figure 3.

The percentage of consonants established within each manner of articulation category by at least half the children with cochlear implants across months of robust hearing experience. Please note that points are offset horizontally for visual clarity.

Figure 4.

The percentage of consonants established within each manner of articulation category by at least half of typically developing children across months of robust hearing experience. Please note that points are offset horizontally for visual clarity.

Figure 5.

The percentage of consonants established within each place of articulation category by at least half the children with cochlear implants across months of robust hearing experience. Please note that points are offset horizontally for visual clarity.

Figure 6.

The percentage of consonants established within each place of articulation category by at least half of typically developing children across months of robust hearing experience. Please note that points are offset horizontally for visual clarity.