Brain scans may allow detection of dyslexia in pre-school children even before they start to read, say researchers.

A US 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.