As more cochlear implants are fitted in pre-verbal children, early language checklists and scales have been used to determine whether language is developing normally. Although research tends to support the validity of checklists as screening tools in normal hearing populations, their sensitivity in detecting pre-verbal children with significant hearing loss who require specialist intensive language training remains to be demonstrated. So that language intervention can take place at the earliest possible time, it is important to determine whether scales and checklists used for infants are correlated with, or even predictive of later vocabulary and language development in toddlers and pre-schoolers

1. Early Language Outcomes For Children Receiving
Implants Under Three Years
Shani Dettman2,3, Yien Ching Ang1, Jaime Leigh1,3, Jennifer Holland1,3, & Richard Dowell1,2,3
1. The University of Melbourne, Dept of Otolaryngology
2. The Cooperative Research Centre for Cochlear Implant and Hearing Aid Innovation
3. Cochlear Implant Clinic, Royal Victorian Eye and Ear Hospital, Melbourne, Australia
Objective
Results for individual tests
Increasing numbers of infants and young children are being diagnosed and referred to
early intervention programs and implant centres as a result of widespread
implementation of neonatal hearing screening programs and greater awareness and
acceptance of cochlear implant efficacy. As more cochlear implants are fitted in preverbal children, early language checklists and scales have been used to determine
whether language is developing normally. Although research tends to support the
validity of checklists as screening tools in normal hearing populations, their sensitivity
in detecting pre-verbal children with significant hearing loss who require specialist
intensive language training remains to be demonstrated.
CDI For the 24 children who completed
This retrospective study examined language outcomes for 141 children who received
their cochlear implant(s) at the Royal Eye and Ear Victorian Hospital, Melbourne
Australia. There were 125 children with congenital hearing loss and 24 children who
had a later onset of hearing loss with the mean onset of hearing loss being 0.16 years
(range 0.00 to 2.40 yrs; SD 0.44). Children who had any evidence of progressive
hearing loss were excluded from the study. The mean 3 frequency pure tone average
was 113 dB HL (range 70 to 125 dB HL; SD 11.45) for the better ear. The mean age
at diagnosis was 10 months with mean age of hearing aid fitting at 1.01 years (range
0.10 to 2.60 yrs; SD 0.52) and mean age at cochlear implantation at 1.75 years (range
0.53 to 2.98; SD 0.62).
The speech processing strategies included ACE or SPEAK with Sprint, ESPrit 3G or
Freedom speech processors. The mean duration of cochlear implant experience was
2.73 years (range -1.58 to 11.85 yrs; SD 2.55).
Children were included if they had a fully functional current speech processing device,
no significant oro-motor dysfunction, English as the predominant language used at
home, and used a communication mode with either aural/oral (n=101) or sign
emphasis (n=36) at home or at school. There were four children where the
classification of communication mode was unknown. Most of the children (n=102) had
average cognitive ability as assessed by an Educational Psychologist. Any children
with poorer than ‘borderline average’ cognitive skills (n=8) were excluded.
Correlation between child demographic/developmental variables and
language outcomes
As may be expected, the age at which a child received hearing aids was correlated
with the age at cochlear implant surgery (r = 0.53; p<0.001), and general device
experience effects were seen. That is, greater experience with the device was
associated with better outcomes for the RI-TLS (r = 0.715; p<0.001) and PPVT (r =
0.774; p<0.001) respectively. Significant correlations between the child’s chronological
age at the time of language testing and the RI-TLS equivalent age (r = 0.574; p<0.001)
and the PPVT equivalent age (r = 0.775; p<0.001) suggest that language performance
improves over time.
Of greater interest to this study were the relationships between communication mode
and language outcomes. Results from all three language measures were poorer for
children enrolled in programs with sign emphasis versus oral/aural emphasis.
Significant correlations were found between sign communication used at home/school
and the RI-TLS (r = 0.369; p<0.001), CDI (r = 0.640; p<0.001) and PPVT (r = 0.198;
p<0.001). This result is complicated by the finding that communication mode at school
was also correlated (r = 0.19; p<0.001) with the cognitive status of the children. Taken
together, results suggest that children with borderline and low average cognitive skills
were more likely to be found in early intervention programs with sign emphasis and
were more likely to demonstrate greater language delays.
There was a significant relationship between the age at receiving the cochlear implant
and the degree of delay on the RI-TLS (r = 0.650; p<0.001) and PPVT (r = 0.431;
p<0.001). Similarly, duration of profound hearing loss was significantly associated with
the degree of delay on the RI-TLS (r = 0.569; p<0.001 and PPVT (r = 0. 404; p<0.001).
These results support the ‘earlier is better’ argument regarding the use of cochlear
implants for infants with significant hearing loss.
For the 89 children who had two or more
PPVT measures, the EA was 3.85 (range
1.80 to 11.40; SD 1.88) and the average
growth RATE was 0.93 (range -0.23 to
3.60; SD 0.62)(Figure 2 below).
Mean slope = 0.93
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6.00
Mean slope = 0.82
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Chronological age (years)
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Chronological Age (years)
Subjects
completed the PPVT, the EA was 3.77
years (range 1.80 to 11.40 yrs; SD 1.80).
The average DELAY was 2.34 years
(range -1.90 to 8.00; SD 1.51).
Equivalent Language Age (years)
This study examined the validity, clinical utility and
RI-TLS n=92
71
correlation of two infant checklists (Rossetti Infant –
PPVT n=118
Toddler Language Scale [RI-TLS; n=92] and the
10
Child Development Inventory [CDI; n=24]),
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13
against a formal receptive vocabulary measure;
Peabody Picture Vocabulary Test of Receptive Language
[PPVT; n=118] for children receiving cochlear implants
CDI n=24
under three years of age.
RI-TLS For the 92 children who
completed the RI-TLS, the EA was 0.78
years (range 0.00 to 3.00 yrs; SD 0.82).
The average DELAY was 1.40 years
(range -0.47 to 6.46 yrs; SD 0.94). For
the 66 children who completed two or
more RI-TLS, the EA was 0.79 years
(range 0.00 to 3.00 yrs; SD 0.83) and the
average growth RATE was 0.82 (range
0.00 to 2.43; SD 0.54) (Figure 1 below).
PPVT For the 118 children who
Figure 1. Individual growth rates for 66 children who
Figure 2. Individual growth rates for 89 children who
completed two or more administrations of the PPVT
completed two or more administrations of the RI –TLS.
Results across the three language tests
Significant correlations were found between the degree of delay measured by the
PPVT and RI-TLS (n=71; r = 0.792; p<0.001), PPVT and CDI (n=13; r = 0.792; p<0.05)
and RI-TLS and CDI (n=22; r = 0.852; p<0.001).
6.00
For the 10 children who completed all three
language assessments, the average
Language growth RATE was 0.90
(range 0.50 to 1.50; SD 0.36)(Figure 3 right).
Equivalent Language Age (years)
Study Design
the CDI, the Equivalent Age (EA) was
1.82 years (range 1.00 to 4.00 yrs; SD
0.75). The average DELAY was 0.93
years (range -2.38 to 3.91yrs; SD 1.45).
Equivalent Language Age (years)
So that language intervention can take place at the earliest possible time, it is
important to determine whether scales and checklists used for infants are correlated
with, or even predictive of later vocabulary and language development in toddlers and
pre-schoolers.
Results for individual tests
5.00
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1.00
0.00
0.00
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2.00
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Chronological Age (years)
To estimate the degree of PPVT delay from RI–TLS delay and CDI delay, the
regression equations were as follows;
PPVT delay = 0.46 + 0.70 RI –TLS delay (R2 = 0.63)
PPVT delay = -0.33 + 1.21 CDI delay (R2 = 0.63)
The results of the regression analyses suggested a significant relationship between the
PPVT delay and the RI-TLS delay and CDI delay. The R2 values indicated that
approximately 63% of the variance in the PPVT delay was predicted by either the RITLS delay or the CDI delay.
Summary and Conclusions
From this study, the children who received cochlear implants before the age of three
years demonstrated a RI-TLS language growth rate and PPVT language growth rate of
0.82 and 0.93 respectively. Normal hearing children demonstrate a growth rate of 1.00,
so these results for children with congenital and early onset profound hearing loss are
quite promising.
Results suggested that the infant checklists (RI-TLS and CDI) were well correlated with
the receptive vocabulary test (PPVT). Children using cochlear implants, who
demonstrated some degree of delay on the CDI or RI-TLS, would also be likely to
demonstrate delays on the PPVT. The CDI and RI-TLS are quite useful to monitor
language development in very young children with profound hearing loss and are
appropriate for clinicians to use when providing feedback to parents. Clinicians can
use these checklists to help parents form realistic expectations and plan appropriate
language goals for children with significant hearing loss.
Acknowledgements to
Children and Families, Speech Pathologists,
Audiologists, Surgeons & Administration Staff of
the Cochlear Implant Clinic, Royal Victorian Eye
and Ear Hospital, Victoria, Australia.
dettmans@unimelb.edu.au