Comparative fMRI Analysis: Reading Networks in Children with Dyslexia

This research project investigates the neural underpinnings of dyslexia using fMRI, comparing brain activation patterns in children with dyslexia, those with functional monocular vision, and typically developing readers. The study aims to identify differences in neural networks related to reading, focusing on phonological and orthographic processing through lexical decision and semantic categorization tasks. By recruiting sixty 9-12 year old right-handed children with English as their mother tongue and normal IQ, the research employs a Philips Achieva 3.0-T MRI system and various cognitive paradigms to analyze brain activity. The findings seek to clarify the relationship between visual impairments and dyslexia, potentially informing early detection and intervention strategies. The ultimate goal is to improve the diagnosis and treatment of reading deficits and retardation.

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Topic: Investigations of reading network disturbances using fMRI in children suffering
from ocular motility
Abstract
Dyslexia is defined as a neurological disorder which has a genetic origin however the
biological as well as the cognitive reasons behind this are still under investigation. This study
aims to undergo a comparative analysis in order to study the difference in the neural
networking among the three groups of children. One with dyslexia and another group with
functional monocular vision and another group are developing readers. The brain activation
pattern in the neural imaging will be done through testing the English reading skills among
the group of children. The brain activation pattern will mainly be studied with the help to
high resolution fMRI tests. The results will help in detailed classification of the neurological
disorder prevailing among the children with dyslexia and other learning disability and its
relation with the vision impairments. The results will help to design phonological awareness
and proper language development for children with dyslexia. This will help in easy recovery
and improvement in the coping skills with learning disability.
Introduction
Developmental dyslexia is a neurological disorder that causes learning disability
among 80% of the children. It is now well-established that dyslexia has a genetic origin
however, the underlying the biological and the cognitive causes which guide the disease
development is still debated (Frith, 2017). However, Saralegui et al. (2014) are of the opinion
that the primary difficulty with respect to dyslexia reflects a deficiency in the communication
skills or language system and visual complications. According to Handler and Fierson (2011)
children with dyslexia suffers from learning disability. Handler and Fierson (2011) further
highlighted that vision problems at times interfere with the process of reading. However,

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children with dyslexia or other children who are suffering from learning disability have
nearly identical visual functions and ocular health status as reflected among the children
without learning disability. Handler and Fierson (2011) highlighted that there is lack of
proper scientific evidence to support this view that subtle eye or visual problems can cause or
increase the severity of learning disability. Quercia, Feiss and Michel (2013) stated that
development dyslexia affects at-least 10% of school-aged children however, a detailed
etiology still remains unknown. One of the widely acknowledged theories in order to explain
the etiology of dyslexia is consistent presence of phonological difficulties in combination
with the inability to manipulate language sounds. Quercia, Feiss and Michel (2013) stated
that anomalies of visual attention along with short visual attention are demonstrated in a
number of cases. Spatial orientation is also affected among dyslexic who experiences a
preference towards spatial attention to the right. This asymmetry cause veritable neglect of
space on the left side. Advent of new explanatory theories further helps in the multimodal
explanation of the visual inputs in dyslexia.
Several theories have been proposed in order to explain the learning disability and
visual deficit associated with dyslexia. Some of these theories include auditory temporal
processing deficit theory, Cerebellar theory and more recently the attention span of visual
deficit theory and Magnocellular visual deficit theory of dyslexia. All these theories causes
deficiencies in cognitive and visual processing leading to learning disability and speech
problems (Saralegui et al., 2014). Rack (2017) proposed that the developmental dyslexia is a
heterogeneous impairment, which results from cognitive disorders that are independent in
nature. Here the majority of the individuals suffer from phonological deficit while other
develop visual deficit. Pammer (2014) stated that children with learning disabilities or
reading disorders have increased incidence of vision loss. Pammer (2014) highlighted that
importance of vision therapy for reading and learning disabilities. However, there is no

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proven difference between readers with optimal and abnormal binocular function. Other
studies conducted by Vagge, Cavanna, Traverso and Iester (2015) failed to highlight that
increase in the rate of incidence of binocular vision problems among the children with
reading ability. The abnormal tracking of eyes is also mistakenly indicated as the main
underlying cause of reading difficulties among the dyslexic individuals (Vagge, Cavanna,
Traverso & Iester, 2015). However, the research conducted by Saralegui et al. (2014)
highlighted that the individuals with almost or complete inability to move their eyes have
normal ability to read and write. From the ophthalmologic point of view it can be stated that
individuals with dyslexia experience identical type of eye movements in the beginning. But,
as dyslexics individuals experience normal sequential saccade tracking in the other areas of
oculomotor functioning, it is assumed that abnormalities visualised in individuals with
dyslexia during reading is an outcome and not the consequence of their reading disability
(Saralegui et al., 2014). In other words it can be said that decoding or difficulties in
comprehension in comparison to primary abnormality of the oculomotor control systems are
reasons behind slow reading along with the higher duration about the fixations along with the
backward saccades.
Hypothesis
The recent studies conducted through the results of fMRI is able to support the
hypothesis that promote visual magnocellular dysfunction is the consequence and the cause
underlying the reading disabilities (Olulade, Napoliello & Eden, 2013). The aim of the
research is to analyse the neural network while studying a group of children with dyslexia
and compare the results with network obtained from the other group of children. The other
group of children mainly encompass typical development complication, children with
monocular vision which is secondary to ocular motility disorders and children who have

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impaired stereopsis and saccadic eye movements under binocular vision. The main
hypothesis behind designing the aim of the research is there is difference in the neuronal
imaging of the children ith dyslexia and other group of children. According to Peyrin et al.
(2012) the difference in the brain scan fMRI results is extremely minute between individual
with or without dyslexia. Thus the research will be conducted over a group of individuals in
order to realiably detect the difference.
The main objective of the study is to analyse whether dyslexic readers have neuronal
patterns which are similar to the group of children with ocular motility disorders. If
difference is found in their neuronal reading networks, then ocular motility disorder will not
be considered as a direct cause of dyslexia. The difference if elucidated in the neuronal
imaging will further help to highlight the ocular movements as experienced by the patients
with dyslexia. According to Vagge, Cavanna, Traverso and Iester (2015) detection or the
identification of the ocular abnormality with the children with dyslexia will help in early
detection along with implementation of the early intervention. Implementation of the early
interventions with dyslexia will help the children to combat with their learning disabilities.
In order to conduct the study within the scope of the research, a comprehensive fMRI
study will be conducted with the use of three different cognitive paradigms. This will help to
explore the two principal domains of reading, phonological and orthographic parameter
(Saralegui et al., 2014). The study will mainly emphasize over the two specific paradigms of
lexical decision in order to elicit the overall activation of the phonological network. The
study will also test the linguistic abilities of the two groups of children through the inclusion
of specific paradigm for semantic categorization in order to activate the orthographic route.
Under this orthographic route a subject has to generate a conceptual representation of two
different cue words and find their respective relationships and compare the same with a
selected group of words in order to determine if it belong under the same category. In relation

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to the fMRI imaging, it can be said that high resolution functional magnetic resonance
imaging of the brain activity pattern that will be elicited by this set of test, reading-based
paradigms will help to compare and contrast the underlying mechanism of dyslexia and its
overall relation to the visual impairment. This will be beneficial consequences for the
diagnosis and corresponding treatment of deficits of the overall reading system and reading
retardation.
Methodology
Participant population- From the department of Paediatric Neurology and Ophthalmology of
a hospital, sixty children will be recruited along with that children from the nearby schools
will be recruited for the study who will be considered as the control. The children will be
recruited only after gaining a written informed consent from their parents. The selection
criteria for the selection of the sixty children were as follows:
Inclusion criteria: The children had to belong to the age group of 9 to 12 years were all will
be right-handed. The left handed children will not be included in the study in order to avoid
the effects of laterality. The selected children should have English as their mother tongue in
addition to having an IQ that is within the normal range, rather with average IQ. This will be
considered in accordance to the Wechsler Intelligence Scale for Children—Fourth Edition,
where the full scale will be IQ > 75 (Watkins & Smith, 2013). Additionally for the children
belonging to the dyslexic group, there will be a requirement for the children to undergo a
diagnosis of dyslexia however who do not have received children along with pycho-
pedagogical support for literacy along with the children being assigned to the monocular
vision group who will be considered as typical readers.
Exclusion criteria: Children having a past medical history of neurological disease or having
symptoms like severe trauma along with impairment of the sensory-motor coordination and

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psychiatric illness will be excluded from the study. Additionally children who were subjected
to continuous drug treatments along with experiencing social deprivation, inadequate
schooling or who are intolerant to MRI scanning due to reasons of claustrophobia, loss of
cooperation will be excluded. Additionally the participants with dyslexia and the control
groups who had abnormalities in vision were excluded from the study. However exceptions
were made in the case the participants having refractive error which is corrected with normal
visual acuity or having abnormalities of mobility on clinical examination.
Data collection- Conduction of the experiments will be on the Philips Achieva 3.0-T MRI
system having a 32-channel head coil. Anatomical acquisition will be carried out through the
MR scanning protocol. For spatial corregistration along with anatomical reference, there will
be implementation of structural MR scan. The BOLD functional images will be acquired
through the three consecutive sequences.
Experimental design-
There will be rendering of the surface of the location of the ROI that will be evaluated
through the fMRI evaluation. For carrying out the definitive cognitive testing in the MR
scanner, the participants of the study will be introduced to the cognitive tasks which will
involve the functioning and displaying of the response systems in a computer system that is
independent of the MR system (Paulesu, Danelli & Berlingeri, 2014). The experiment will
involve lexical decision tasks where the first task will involve making the participants read
two-syllable real words or the pseudowords. This will be followed by the second
lexical/orthographic matching task involving the two sets of two-syllable pseudo words that
will be displayed in a simultaneous manner. This will be followed by the third task that is the
semantic categorization task. Here three words will be presented in a simultaneous manner,

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where two from the same semantic category will be placed at the top of the display however a
third word will be shown at the bottom.
Data processing- In order to summarise the distributions in respect to the study variables and
the demographic variables there will be use of the descriptive statistics. For the comparison
between the socio-demographic and neuropsychological features there will be
implementation of the non-parametric test like KW test, Wilcoxon rank sum test and the
Pearson's chi-square for categorical variables (Zhou, Xia, Bi & Shu, 2015).
Ethical considerations- Abiding by the code of Ethics of the World Medical Association the
research will be performed along with the approval of the Clinical Research Ethics
Committee of the concerned hospital were the experiment will be performed. An informed
consent will be made to sign by the parents or the guardians of the participants who were
recruited in the study. There is also a requirement for all the participants to be informed about
the purposes and the protocols of the proposed study.
Expected results
For this study, the results will be presented for each of the paradigm separately. In terms of
the lexical decision, the group contrasts will show that in case of the dyslexic children there is
a possibility of reduced activation in the area of the right Broca. The tests carried out will be
able to show the significant difference between the left Broca’s area and right Broca’s area.
Lexical decision making
There will be six areas that will be studies in the ROI analysis of this task. In terms of the
correlation of the score with respect to the three paradigms, the comparative analysis that will
be performed will be able to show the areas of activation of the cortical with the three

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variables. This is thought to reflect in the best way the reading ability of the children. This
will provide the accurate scores and the accurate clinical timing for the execution of the
pseudo-word reading task that will be involved in the reading process evaluation. In regards
to this, the fMRI analysis as proposed will depict the group differences in terms of the mean
activation with respect to the three groups in the selected areas along with the pseudoword
condition of reading of the task of lexical decision.
Lexical or orthographic matching
There will be eight areas that will be studies in the ROI analysis of this task. It is expected
that there will be reduced activation in dyslexics in the left and right Broca's areas in
comparison to the other groups, however it will not be established until there is a statistically
significant difference obtained. It is also expected that there will be significant differences for
both right and left superior parietal lobes , where the left hemisphere will show an activation
that is in significant difference to the DXRs with TDRs and for the right hemisphere there is
significant differences will be found between DXRs and TDRs.
Semantic categorization
There will be eleven areas that will be studies in the ROI analysis of this task. In this case
there will be an expectation of obtaining significant differences between groups that will be
found for both left and right Broca’s area. Similarly it can be expected that for the other tests
a same trend in the data will be found and for the activation in dyslexics there will be some
difference in the TDR and the MVRs. In case of the left MTG, it was expected that there will
be reduced activation in the TDR group as compared to others. However for that of the right
MTG area, there is a tendency for high activation in the readers who are dyslexic in
comparison to the other two groups.

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Variation between paradigms
For the Lexical Decision task, there will be a probability of obtaining large differences
between the TDR and DXR groups. In the Lexical/orthographic matching task, there is
probability of obtaining that the left Broca's area will involve major differences between the
DXR and TDR groups. In the Semantic Categorization task, the probability is that the right
Broca's area will show higher differences between the groups.

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