Bilateral Cochlear Implantation in Children. The Simbici project, providing evidence

In recent history, there has been extensive debate on the effectiveness of
bilateral cochlear implantation (CI). Published literature mainly focusses on
speech recognition and localisation capacity, and the level of evidence is low.
Based on these data, some countries have implemented reimbursement for
bilateral treatment, where other countries have not. In order to consider
bilateral cochlear implantation in children in The Netherlands for regular
reimbursement, the added value of providing two implants should at least be
made plausible.

Animal and man hear with two ears. Bilateral sound cues are integrated
centrally, providing important advantages compared to unilateral hearing.
binaural hearing provides localisation, sothat we can detect from which
direction sound, and therefore danger comes from. Filtering out noise form the
speech signal, improves speech recognition-in-noise.

In children with bilateral sensorineural hearing loss or deafness, two implants
could give added value compared to unilateral implantation in three domains.
Primary auditive capacities like speech recognition and localisation could
improve. Evidence of this has been provided. Second, language development and
auditive memory may improve. And thirdly, there may be an effect in the
psycho-social and social-emotional domain.

The objective of the Simbici project is to evaluate the effect of bilateral
cochlear implantation compared to unilateral cochlear implantation in children,
in the domains of primary auditive capacities, language development and
social-emotional development

The Simbici project concerns a pilot study, with prospective evaluation of
children after bilateral and unilateral cochlear implantation. In order control
for confounding factors, pre-operative tests will provide data on communication
ability and cognitive development (see further). Descriptive data acquired from
the present study may be useful for the power analysis of future trials.

Uni- en bilateral cochlear implantation.

The aim of this study is to investigate if simultaneous bilateral cochlear
implantation in children shows a bilateral advantage in comparison to
unilateral cochlear implantation in children on auditory, language and
psychological tests. In 2009 the Dutch Health Care Insurance Board indicated
that at this moment the available evidence is not sufficient enough to approve
the advantage of bilateral cochlear implantation in children compared to
children with a unilateral CI. They indicate that reconsideration will occur if
publications from Dutch origin become available on speech perception and the
acquisition of spoken language in children with prelingual severe to profound
hearing loss with bilateral CIs. Given the value of this pilot study for future
trials and in the light of the very small burden for the children, the study is
justified. Subjects will only be subjected to extra investigations before
implantation, and once at the age of 4 years in which they will not be at any
risk. Results of the study can also contribute to the knowledge of the
professionals surrounding CI children. Children with severe to profound hearing
loss and their parents can be counselled properly to obtain the best results
with their CI(s).