dryriver writes "Brain scans may allow detection of dyslexia in pre-school children even before they start to read, say researchers. A U.S. team found tell-tale signs on scans that have already been seen in adults with the condition. And these brain differences could be a cause rather than a consequence of dyslexia — something unknown until now — the Journal of Neuroscience reports. Scans could allow early diagnosis and intervention, experts hope. The part of the brain affected is called the Arcuate Fasciculus. Among the 40 school-entry children they studied they found some had shrinkage of this brain region, which processes word sounds and language. They asked the same children to do several different types of pre-reading tests, such as trying out different sounds in words. Those children with a smaller Arcuate Fasciculus had lower scores."