Shocking  [A]s many as 20 percent of schoolchildren may have a neurological deficit, ranging from mild to severe, that makes it hard for them to read and write.
More than 50% of schoolchildren have severe neurological deficits. 
mnli hypothesis: More than 50% of schoolchildren have severe neurological deficits.  premise: Shocking  [A]s many as 20 percent of schoolchildren may have a neurological deficit, ranging from mild to severe, that makes it hard for them to read and write.