A Matter of Balance

Many dyslexics not only have reading problems, but also poor motor coordination. Below the back of the cerebral cortex lies a separate part of the brain, the cerebellum; this is the brain’s motor control autopilot. It receives most of its information from the magnocellular systems, and it is mainly responsible for coordinating movements.

Our and other’s recent research has shown that development of the cerebellum may be mildly impaired in dyslexia. Conversely we have found that some children with cerebellar damage may first present to the doctor with reading problems. So we have been comparing cerebellar function in good readers, developmental dyslexics and in children with severe cerebellar damage caused by tumours. We’ve measured how well they can keep their balance, quickly point to small targets and how quickly they can learn a sequence of finger movements.

The dyslexic group was indeed slightly worse than control children at fast pointing, keeping their balance and at learning the motor sequence, i.e. some dyslexics do seem to have mild cerebellar impairments. However the coordination of the children with overt cerebellar damage was far worse than their reading, whereas the reading of the dyslexics was far worse than their coordination. Hence even though the cerebellum may be slightly affected in dyslexia, this is unlikely to be the main cause of their reading problems. Therefore the expensive balance exercises that have been widely advertised will probably not help many dyslexics' reading very much, but this kind of treatment still needs proper investigation.