 Working in the 1920s, Orton did not have access to modern brain scanning equipment,
but he knew from his work with brain damaged adults that injuries to the left
hemisphere produced symptoms similar to those he observed in children.Many of the children Orton studied were also ambidextrous or had mixed handedness.This led Orton to theorize that the children's reading problems stemmed from the failure of the left hemisphere to become dominant over the right.