Verb processing and word learning in DLD: Diagnostic tests and neural correlates

Children's vocabulary knowledge is an important predictor of educational level
and socioeconomic status. About 7% of children present with a Developmental
Language Disorder (DLD) which is a neurodevelopmental disorder. Auditory verbal
learning, the auditory encoding of speech in phonological short-term memory,
its storage, and retrieval, is a key skill in vocabulary development and is
often impaired in children with DLD. Nonetheless, the neuroanatomical
correlates of verbal learning in this clinical population have not been
investigated. These could help us understand the nature of the verbal learning
problems and could lead to new treatment possibilities. The few studies in this
field were conducted with elderly individuals, individuals with amyotrophic
lateral sclerosis, children or adults with traumatic brain injury. None of
those studies had a focus on learning of verbs, all using nouns as experimental
stimuli. Children and adults with DLD present with atypical brain structure in
several cortical and subcortical regions, and prominent impairments in auditory
verbal learning. These two properties render individuals with DLD an ideal
population to study the neural correlates of verbal learning with both nouns
and verbs.

There is no standardized test available, however, which studies verbal learning
ability using verbs. Also, the language ability of these children is typically
evaluated using standard assessment batteries, all of which predominantly use
tasks with nouns, and not with verbs, even though children with DLD have
greater difficulties with verbs. understanding the processing nature of those
difficulties is essential to characterize the nature of language impairments at
the sentence level.

The objectives of the proposed research are:
(1) to characterize the neural correlates of verbal learning abilities (both
for nouns and verbs) in typically developing (TD) children compared to children
with DLD, aged 8-12 years old.
(2) to standardize a novel diagnostic verb processing test battery including a
verb learning test for children aged 8-12;
(3) to describe the differences between auditory verbal learning, verb
processing, and verb learning in TD children compared to children with DLD aged
8-12

This is an observational study. TD children (n=60) and children with DLD (n=40)
aged 8 to 12 will be recruited from regular and special education (cluster 2)
schools. All children will participate in 3 testing sessions. In these
sessions, the developed language tests as well as already existing standardized
tests will be administered. In addition, 25 TD children and 25 children with
DLD will be invited for one magnetic resonance imaging (MRI) session within 1
month of testing session 2. Children that participate in the MRI session, will
complete an MRI scan and language tasks during testing session 3.

MRI has no known negative effects on health, and it is a standard brain imaging
technique. There is a risk for individuals with any metal devices in their
body, and these will not be allowed to participate. MRI involves lying still in
a confined environment, which is difficult for children. During acquisition the
scanner makes loud noises. Ear plugs will be provided, but noise is still
audible and can be burdensome. For these reasons, the MRI acquisition will not
be longer than 30 minutes with the session extending up to 1h (including 30
minutes of preparation time). Children and parents will be able to view an
animated cartoon illustrating the procedures of the MRI session and children
will go through a planned playful preparation to minimize any potential worries
related to taking part in MRI acquisition. To minimize boredom, participants
will be allowed to watch a movie during MRI acquisition, since no language
tasks will be administered.

For the behavioral assessments, participants will be required to participate in
2 testing sessions of approximately 1 hour and 1 testing session of 30 to 45
minutes, taking place across three weeks. These sessions will be planned in
schools (in which case the child is taken out of the classroom for that period
of time). Testing may also be planned at the parents* home or a lab at the
university, in case the parents prefer this or the school is unavailable for
on-site testing due to the pandemic. There are no expected risks of
administering these pen-and-paper or computer-based tests. For children that
participate in the MRI session, testing session 3 will take place at the UMCG
and will last approximately 1 hour.

Although conducting this research with adults would be easier, the newly
developed tools are designed for language assessment in this younger age group.
Furthermore, the documentation of neuroanatomical correlates of verbal learning
in this population can be of key importance to understanding why children fall
behind on vocabulary development and it may stimulate the development of
treatment approaches, including neuromodulation to relevant brain regions.
Findings based on research with adults would not be directly transferable for
these purposes.