Top-Down Enrichment of Speech Perception

The current project aims to investigate the potentially beneficial effects of
musical training on speech perception, especially for hearing-impaired (HI)
individuals. HI individuals and cochlear implant (CI) users have difficulty in
processing auditory information, especially in noisy surroundings (Moore,
2003). Earlier studies have shown that normal hearing (NH) musicians, compared
to NH non-musicians, have an advantage when processing speech in particular in
noise or in competing talker situations (Ba*kent & Gaudrain, 2016; for a review
see Coffey, Mogilever, & Zatorre, 2017). Whether musical training may enhance
speech perception under adverse conditions, such as in the presence of noise or
multiple talkers, stands in the center of this project, as it can have benefits
for our patients in clinical rehabilitation. Such an enhancement in musicians
may be due to strengthening of the shared neural resources (Patel, 2012) or
increased plasticity in the auditory system (Pantev & Herholz, 2011). However,
the source of this possible advantage, coined the *musician effect* in speech
processing under adverse conditions, is still unclear (Ba*kent & Gaudrain,
2016; Fuller, Galvin, Maat, Free, & Ba*kent, 2014).
It is an open question to what extent the *musician effect* in speech
processing relies on domain-specific processes or whether there is a general,
across-domain transfer that makes use of a shared network. The current study
aims to investigate the various levels of speech and music processing,
especially in adverse listening conditions, in order to identify the nature of
the *musician effect*. If there is such an effect, understanding the underlying
mechanisms would be important in designing most optimal rehabilitation tools
for the patient populations.

The main objective is to identify the source of the *musician effect*,
particularly for speech perception. The underlying processes involved and
individual differences in different groups of participants in speech and music
perception, both in quiet and adverse conditions, of musician and non-musician
NH/HI individuals with and without hearing aids will be systematically
investigated.

The current study has two parts that will investigate two main questions:
Part I. Are there differences in musician and non-musicians speech and
music processing? To what extent are these differences based on domain-general
or domain-specific mechanisms?
Part II. Are there differences in musicians and non-musicians in the
way that they can use sensory cues in predictive processing of speech?

Since both musicians and HI groups present high heterogeneity, the study design
will accommodate individual differences within the target populations, due to
different musical expertise and due to different hearing loss histories and
etiologies. Per participant the study will include a series of behavioral,
eye-tracking, pupillometry and EEG measures, which will then be jointly
analyzed to provide profiles of individual listeners. The experiments will
investigate domain-specific processes, such as linguistic and musical abilities
and psychoacoustic sensitivities, as well as domain-general processes, such as
attention control.

There are no known risks or benefits associated with the participation in the
experiment. Participants will be given opportunities to take breaks during the
experiment.