Dyslexia affects more than the ability to read. Children with dyslexia perceive visual information more slowly than their normally developing peers, according to a new study published in JNeurosci.
Some researchers believe that dyslexia is a violation of visual processing at its core, because the brain pathway involved in the processing of movement also changes in dyslexia. However, there is a debate as to whether impaired processing of movements leads to dyslexia. Some argue that we may be able to improve our reading skills in dyslexia by practicing visual processing skills.
In a new study by Manning et al., Children aged six to fourteen observed a mass of moving points and identified their mean direction of movement while the researchers measured their brain activity with an EEG. Mathematical modeling of their response time and accuracy revealed that children with dyslexia take longer to gather visual evidence than their normally developing peers. Behavioral differences also correspond to differences in brain activity. Synchronized activity in the central parietal regions, the areas involved in decision-making, is constantly increasing until the child makes a decision. This increase in brain activity occurs more gradually in children with dyslexia. These results suggest altered movement processing and decision-making in dyslexia, the cause of which remains unknown.
Manning, S., et al. (2021) Visual movement and decision making in dyslexia: Decreased accumulation of sensory evidence and associated neural dynamics. JNeurosci. doi.org/10.1523/JNEUROSCI.1232-21.2021.