The Development of Advanced Reading Skills: Normalization and Compensation Effects among Children with a Familial Risk of Dyslexia - an fMRI study

In our modern society reading is a very important skill. However, for a small
subgroup of about 5 percent of the population reading is a skill that is very
hard to acquire. This group of children is often diagnosed with dyslexia. They
show persistent difficulties with the decoding of words from letters to sounds
despite a normal intelligence and adequate schooling. Dyslexia is partially
hereditary; children with a parent with dyslexia have a risk of 30-60% to
develop dyslexia themselves. It has been shown that children and adults with
dyslexia show different patterns of brain activity during reading tasks in
comparison to control groups.

By the end of primary school, some but not all children with dyslexia have
problems with more advanced reading skills, resulting in text comprehension
difficulties, as well as problems with reading and spelling in a second
language. Furthermore, the final reading level that children with dyslexia
achieve is highly variable. There is relatively little research that has
investigated the different outcomes of dyslexia. The present study aims to
change this by linking patterns of brain activity as obtained with functional
Magnetic Resonance Imaging (fMRI) and brain structural connectivity as obtained
with Diffusion Tensor Imaging (DTI) to advanced reading skills, and to data
collected in a longitudinal study of dyslexia. This study follows up on an
electroencephalography (EEG) study in the same population to investigate the
neural generators underlying differences in reading skills between control
children and children with dyslexia.

Our main objective is to investigate if and how advanced reading and writing
skills as well as reading and spelling in a second language, develop among
children who have a familial risk of dyslexia in comparison to a control group.
Here, we would like to investigate how at-risk children with and without
dyslexia differ at the behavioural level, and relate such differences to
measures of brain function and brain structural connectivity as obtained with
fMRI during reading tasks, and DTI. This will allow us to determine whether
normalisation or compensation (in comparison to the control group) takes place
in the brain among the better at-risk readers.

A quasi-experimental approach will be used. Children with a familial risk for
dyslexia will be compared with a control group, and within the at-risk group a
comparison will be made between children with and without dyslexia.

The children and their parents will be invited to the NeuroImaging Center (NIC)
for two half-day visits with preferably maximum 4 weeks in between. On the
first visit, during an (approximately) 90 minute session the behavioural tests
will be administered, and on the same day, the child will be familiarized with
the scanner environment using a practice (dummy) scanner that is available at
the NIC. This part will last approximately 30 minutes, such that in combination
with breaks, the first visit will last approximately 2.5-3 hours. On the second
visit, the child will participate in the MRI-experiment which will consist of
two fMRI scans (two tasks), a standard anatomical scan (needed for analysis)
and a DTI scan. The child will be in the scanner for maximum 45-60 minutes, and
including preparation and debriefing, this visit will last approximately 1.5-2
hours. Participants will be scanned using a 3 Tesla scanner. There is ample
experience with this scanner using similar paradigms at the NIC in adults. So
far, no negative effects of scanning are known, as long as standard precautions
for MRI research are taken (particularly exclusion of participants with metal
implants or that are (possibly) pregnant).