Dyslexia impacts more than reading ability. Children with dyslexia pick up visual information slower than their typically developing peers, according to new research published in JNeurosci.
Some researchers believe dyslexia is a visual processing disorder at its core because a brain pathway involved in processing motion is also altered in dyslexia. Still, a debate rages over whether impaired motion processing drives dyslexia. Some have argued that we may be able to improve dyslexic reading skills by training visual processing skills.
In a new study by Manning et al., children from ages six to fourteen watched a mass of moving dots and identified their average direction of motion while the researchers measured their brain activity with EEG. Mathematical modelling of their response time and accuracy revealed the dyslexic children took longer to gather visual evidence than their typically developing peers. The behavioral differences corresponded to differences in brain activity, too. Synchronized activity in centro-parietal regions, areas involved in decision making, steadily increased until the child made a decision. This ramping up of brain activity happened more gradually in children with dyslexia. These results suggest altered motion processing and decision-making in dyslexia, the cause of which remains unknown.
Manning, C., et al. (2021) Visual motion and decision-making in dyslexia: Reduced accumulation of sensory evidence and related neural dynamics. JNeurosci. doi.org/10.1523/JNEUROSCI.1232-21.2021.