Reading and spelling disorders can include problems memorizing how words are spelled correctly while reading. A new study now shows that dyslexia also affects brain processes that have nothing to do with reading or writing, including the visual processing of movements. In the experiment, children with dyslexia took longer than their peers to recognize in which direction a mass of points were moving. The findings could also be understood using brain wave measurements. The researchers hope that their findings will help to provide more effective support to those affected.
Around five percent of children in Germany suffer from reading and spelling disorders. They are typically very slow to read, often twisting letters and having difficulty spelling words correctly. This often leads to school and psychological problems, including bad grades, fear of school, lack of self-esteem and sadness. The causes of dyslexia are still largely unclear – and specifically adapted offers of help are limited. Among other things, researchers are discussing whether dyslexia is essentially a disruption of visual processing.
Disturbed processing of movements
A team led by Catherine Manning from the University of Oxford has now used new methods to investigate how visual processing and brain activity differ in children with and without dyslexia. To do this, they presented 100 children aged six to 14, half of whom suffered from dyslexia, a mass of moving points. While the researchers measured the children’s brain waves using electroencephalography (EEG), they were asked to decide in which direction the majority of the points were moving.
The result: children with dyslexia took longer to grasp the visual clues and come to a decision. In addition, they were less precise than their peers. These differences could also be seen in brain activity. In all children, the activity in brain regions involved in decision-making increased steadily until the child made a decision. However, this increase in brain activity was slower in children with dyslexia. Based on the brain activity during the task alone, the researchers were able to identify which EEG data came from children with dyslexia.
Opportunities for more targeted funding
“These results show that children with dyslexia have difficulties with reading and writing,” says Manning. “Instead, children with dyslexia as a group also show differences in the processing of visual information and in making decisions about it.” Previous research had suggested that there may be a connection between dyslexia and impaired visual movement processing. The current study supports this thesis.
“Future research will show whether these differences in visual processing and decision-making can be trained to improve the reading skills of affected children or to obtain clues about the causes of dyslexia,” says Manning. It is already known that dyslexia is not related to decreased intelligence or general difficulty concentrating. A more precise understanding of the underlying neural processes could help to develop targeted support programs that can prevent school problems and the psychological complications that are often associated with them.
Source: Catherine Manning (University of Oxford, UK) et al., Journal of Neuroscience, doi: 10.1523 / JNEUROSCI.1232-21.2021