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The Evaluation of Auditory Perception in Pre-lingually
deafened Children:
Effects of Aetiology, Age at Implantation and other Pre-operative Parameter
MED-EL World-Wide Headquaters, Innsbruck,
Austria
Abstract
A multi-centre investigation is currently underway to examine and monitor auditory
progress of children using the MED-EL multi-channel cochlear implant system
with a high rate CIS/CIS+ strategy by means of EARS (Evaluation of Auditory
Responses to Speech).
This test battery has been, at present, adapted into 17 different languages
and incorporates the Listening Progress Profile (LIP), closed-set MTP (Monosyllable,
Trochee, Polysyllable), closed-set sentence-level test (Tyler-Holstad), open-set
words, GASP sentences and open-set sentences (language specific sentence test).
Two questionnaires, the MAIS and the MUSS are employed for use with both parents
and teachers. The different tests are administered pre-operatively and at designated
intervals post-operatively.
At present, data of more than 500 pre-lingually deafened children, between
0;5 and 17;99 years is available and has been analysed. This preliminary data
indicate that a major benefit is obtained in all age groups on closed and open-set
tests. However, children implanted before the age of 3, show a steeper progress
in time.
Preliminary data will be presented and discussed for all age groups, demonstrating
the children's progress over time.
Methods and materials
In April 2002, the EARS database consisted of 526 study children. These children
originated from different countries (fig. 1) and ranged in age between 0 and
18 years of age. All these children were tested with the different subtests
of the EARS test battery at preset intervals. (pre-operatively, 1 month, 3
months, 6 months, 12 months and on a yearly basis)
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Fig. 1: countries
of origin |
Results
Within figures 2-5, scores for different subtests of the EARS battery are shown.
For all the subtests, results are presented for children implanted between
the age of 0 and 3 years, 3 to 6 years, 6 to 10 years and 10 to 18 years.
Figure 2 demonstrates the results on the LiP test. It is shown that the youngest
group starts from a lower level due to the fact that these children didn´t
have aural rehab or a limited period of hearing aid use before the implantation.
The older groups demonstrate ceiling effects from 6 months on.
Within fig. 3, results on the MTP (word score)
are shown. Similar patterns as on the LiP can be seen. However,
differences between the different age groups are more significant.
Children who are implanted at a young age have a very steep progress
over time.
Results on the open set word test (fig.4) are very different from the previous
two graphs. All age groups start more or less from the same level and there is
a trend noticeable that after 2 months, the youngest seem to overtake the other
groups.
Finally, results on the open set sentence test are given in fig. 5. It is obvious
that the oldest group at implantation is initially benefiting from the
early amplification and rehabilitation. However, after a follow-up period
of two years, all groups reach a level of 50% open set sentence understanding.
This includes that the youngest group already reaches this score before
the age of 5.
Conclusions
After cochlear implantation, all groups show significant improvement over time
on subtests of the EARS-testbattery. There is currently a trend that the group
of children which is implanted below the age of three, seem to have a steeper
and faster progress in comparison to the other age groups. However, it is important
to state that even after 2 years, all age groups keep showing an increase of
performance on the different test levels.
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