Musician effect in normal hearing children and prelingually deafened pediatric and adolescent/adult CI users.

Cochlear implants (CIs) are prosthetic devices that restore hearing in profound
deafness. Improvements in device design have produced good speech understanding
in quiet, but speech perception in noise and enjoyment and perception of music
are still not satisfactory. This is a factor that could profoundly affect the
quality of life for many CI users, as CU users rank music after speech
perception, as the second most important acoustical stimulus in their lives.

In addition to potential benefits for quality of life, exposure to music or
musical training may also pose specific benefits for speech and sound
perception. In normal hearing (NH) listeners, long-term musical experience can
change the sound representation in the auditory system. Enhanced subcortical
and cortical representation of speech and brainstem encoding of linguistic
pitch are observed with musicians. These findings suggest that there may be a
shared neural basis for music and language processing. Perhaps as a result of
this, long-term musically experienced NH adults understand speech in noise
better than non-musicians do. This effect may even be more robust in children
because of neuroplasticity. Auditory plasticity is stronger in children than in
adults. Four years of musical training during childhood leads to more grey
matter volume in certain parts of the brain.
Our previous research, has shown that musical training in adult CI users may
help them better perform in some specific tasks, such as better identification
of emotion in spoken speech. However, this population only included
postlingually deafened adult CI users. Also, a musician effect was shown in
speech intelligibility in acoustic simulations of CIs; in one of the speech in
noise conditions there was a significant, although limited, benefit for adult
musician . However, this benefit was rather limited, again, when observed in
the adult population.

In this project, we would like to follow up on our earlier research with two
new populations. 1) We hypothesize that pediatric musicians may show better
results in music and speech perception tasks than pediatric non-musicians with
and without CI simulation. This because of the positive effects of musical
experience on music and speech perception that we found in adults. Moreover we
expect these results to be stronger in comparison to the adult musician
population, because of and the stronger brain neuroplasticity of children. 2)
We also expect to a musician effect in prelingual CI users and hypothesize that
musical training may be beneficial in the prelingually deafened, CI users.
Musical training could possibly lead to better music perception and better
speech perception skills in this population, which is even more important for
this population because of the limitations already present due to their CI
device. This population is an unusual one, as the prelingual children acquire
their speech language development through their CI. Additional benefits in
music contour identification, emotion identification and in speech perception
would add to their possibilities in communication. For the prelingual adult
population, who acquired speech language development based on their normal
hearing before they turned deaf during early childhood, or on residual hearing
before it started deteriorating, the effects of musical training could be
smaller also because of less plasticity. If such relations as improvement of
speech and music perception due to musical experience indeed exist, this may
lead to the recommendation to implement musical training in the revalidation
program of CI users. Such training may be even more important for both
pediatric and adult prelingual deafened CI users, as they develop their
language skills totally or partially via the CI. The population of healthy
pediatric normal-hearing partiicipants will be included as a control group for
the test group, as they provide baseline data on normal developmental
trajectory of the factors studied with the test groups. This way we will be
able to see if the effects we see in the study are within the normal
developmental range, or if they really come from other factors, such as hearing
impairment. This control group will be tested with the same protocol.

The objective of this study is to identify the effect of musical experience and
training on the perception of speech in quiet and in noise, as well as on
perception of music-related stimuli, such as, pitch, timbre, emotion and melody
recognition, in normal hearing pediatric listeners using non-processed
acoustical stimuli and cochlear implant simulations, as well as in prelingually
deafened pediatric and adult CI users. Further, for a comparison of CI children
to normal-hearing children, the developmental trajectory of the normal-hearing
children will be assessed with a younger and an older age group of
participants.

Part I: Case-control study. The participants listen to acoustic stimuli and the
perception is measured via percent correct scores per test.
Part II: Intervention study. Both groups of prelingually deafened CI users will
be randomly divided between an a musical training group and a control group.
Before and after the training, which takes place during 8 weeks with weekly
training session of 1,5 hour, testing is performed. Speech perception in quiet
and noise, melodic contour identification and emotion recognition was tested
following the standardized test condition as also used in part I of this study
proposal.

There is no know risks or benefits associated with the participation in the
experiment. The two/three sessions last for about 2.5-4 hours, totaling to a
max of 8 hours of testing. Adequate breaks are built into the experiment.
The minor modifications in testing time, setting, or screening come from the
fact that we include younger children in the control group. For these younger
children, these will be adjusted to fit their limited attention span, to
provide the most optimal comfort to them, while also being able to collect data
in the most reliable way. Also these children may be not tested with the entire
set of experiments, but only with selected ones, again to accommodate for the
age-related limits in attention span. Otherwise all test and control groups
will be tested with the same protocol and methodology.