A learning disability in reading is one of the most common neurobiological diagnoses in
school-aged children. Statistics Canada reported that 3.2% of children in Canada have a
learning disability (LD), making LD the most prevalent type of childhood condition. The
new definition of LD has become more complicated to diagnose and treat children. Canadian
universities invested recently in conducting research that tracks neural changes in the
identification and remediation of LD. Electroencephalography (EEG) is one of the most
common tools to inquire about brain information processing and neural changes. However,
only one German study has used a reading intervention and EEG to track neural changes of
children with LD in reading. This study delivered two reading interventions but did not
report which intervention affected reading improvement. Hence, little is known about
reading interventions that would induce positive neural changes in young children with
LD. This proposal aims to implement a specific reading intervention in children and track
neuronal changes. The results of this proposal will be invaluable in improving the
predictive tools we use for early diagnosis of LD in reading, identifying better-targeted
reading interventions, and in better allocation of resources to health and educational
services.
To understand how the brain processes language in real-time, Event-Related Potential
(ERPs) studies have been commonly used to assess the neural underpinnings of reading
disability (RD), especially in children. Of particular interest, the N400 is a negative
ERP waveform peaking at 400 milliseconds that is sensitive to the lexico-semantic aspect
of language. The N400 represents an important language-relevant measure that can be used
to investigate the neural basis of reading comprehension acquisition in typical readers,
a process critical to reading development in school-age populations. The N400 assesses
lexical-semantic processing when a student is introduced to a sentence with a pseudoword
or a semantically incorrect word, as in "the pizza was too hot to cry." The N400 is
sensitive in typical readers, indicating that they understand the semantic incongruity.
There is also evidence that the N400 is atypical in individuals with reading disabilities
and reading comprehension deficits.
These brain-based explanations give educational practice and understanding of the neural
processes underlying reading difficulties, reading comprehension deficits, and
potentially effective intervention mechanisms. Several studies demonstrate the potential
relevance of neuroimaging for identifying a reading disability. Researchers have also
shown that neural changes occur after a successful reading intervention. However, it
remains unknown whether a reading intervention modulates reading-relevant brain activity,
such as that of the N400.
One common approach to this problem is to teach common exception words by sight. An
alternative approach some researchers have proposed is that in addition to teaching
phonics, children are to be trained to "generate alternative pronunciations when they
come to unknown words until they produce a pronunciation that is a real word, and which
makes sense in context". This process is known as Set-for-Variability (SfV). For example,
a child is taught the standard pronunciation of "ch" in the match, hatch, and catch. The
child would then use this regularized pronunciation of "ch" to read the word stomach, an
irregular spelled word. If a child fails to read the irregularly spelled word stomach
using regularized pronunciation, then "the child has to change one or more sound
associations and try again". Set-for-Variability is "the ability to determine the correct
pronunciation of proximation to spoken English words". This means making a link from
'spelling pronunciations' (the product of synthetic phonics such as 'c'-'a'-'t' from the
printed word 'cat') to a conventional pronunciation of that word. If pronouncing a word
does not produce a meaningful phrase in context, the individual would need to try a
different pronunciation.
The proposed study is a randomized-control study where thirty-eight students aged 6-7
years with a reading disability will be randomly assigned into a control and intervention
group. The participants will be matched on age, IQ, and reading level before
randomization. Participants in the control group will be included in a Current Best
Practices (CBP) group and exposed to an intervention that focuses on grapheme-phoneme
correspondence rules. In addition to the CBP, participants in the intervention group will
receive 8-10 weeks of the Set-for-Variability intervention. Pre-post behavioural measures
will be conducted to see if the Set-for-Variability intervention impacts word reading
measured using validated assessment tools and the N400 amplitude. The present research
will provide the first empirical data on the neural changes following a
"Set-for-Variability"-based reading intervention.
