T
he brain structure of a dyslexic child could be different to that of a youngster without the condition.
The structural connectivity of a dyslexic child’s brain could be different to that of a typically developed child, a new study has suggested.
Dyslexia is a common learning difficulty that primarily affects the skills involved in the reading and spelling of words. This includes struggling to recognise and decode words, and problems with comprehension. According to the NHS, an estimated one in ten people have dyslexia to some degree, with the condition affecting individuals from all walks of life.
Over the years, scientists have conducted copious amounts of research into discovering the exact cause of dyslexia. Specialist brain scans, in particular functional magnetic resonance imaging (MRI) scans, have shed light onto reduced functioning of an area near the back of the brain called the occipito-temporal cortex.
However, little research has been performed on the sub-cortical brain regions that involve processes such as short and long-term memory, decision making and emotional reactions – all of which are affected in someone with dyslexia.
Researchers at Vanderbilt Peabody College in the US set out to examine the structural differences in the brain connectivity of 20 children with developmental dyslexia, compared to 20 typically developing readers. All participants were aged between eight and 17.
Focusing on the sub-cortical thalamus brain region, they used a specialised neuroimaging technique called diffusion tensor imaging (DTI), which works by visually mapping the structure of the brain.
The thalamus plays an important role in the brain and has multiple functions: it processes and relays sensory and motor information to different subcortical regions via nerve fibres that make up part of the brain’s white matter; and also regulates states of sleep and wakefulness, including arousal and the level of awareness.
It was hoped that the DTI method would produce a clearer picture of the thalamus and enable the researchers to gain a better understanding of its role in reading behaviour.
The results showed that in the dyslexic group, a different pattern of thalamic connectivity was found in their sensorimotor and lateral prefrontal cortices – in comparison to these brain regions in the typically developing group.
Commenting on the findings, lead researcher Laurie Cutting said: “These results suggest that the thalamus may play a key role in reading behaviour by mediating the functions of task-specific cortical regions.
“Such findings lay the foundation for future studies to investigate further neurobiological anomalies in the development of thalamo-cortical connectivity in individuals with dyslexia.”
In a related study, the scientists decided to investigate the structural connectivity patterns in the left occipito-temporal region of the brain, which is important for reading.
Although past research has shown this area to have reduced functioning in people with dyslexia, few studies have focused on its visual word form functionalities.
The team set out to do so by performing diffusion MRI on the occipito-temporal region and surrounding area in 55 dyslexic and typically developing children.
Again, the brain structure differed between the two groups; those with dyslexia displayed greater connectivity to the regions involved with memory and vision, while the typically developing readers displayed increased connectivity to linguistic regions.
These studies reinforce the need to provide dyslexic children with additional help and support – both in school and at home.
One way in which teachers and parents can do so is by making use of assistive technologies. These digital software programs are interactive learning tools designed for people with learning difficulties. They involve a series of games and activities, which are a fun way of enhancing a child’s literacy and numeracy skills.