My sons tutor also recommended omega 3 because he has quite a short attention span and gets VERY easily distracted, tending to start doodling pictures etc and not really listening. He has verbal dyspraxia and tends to 'go off on a tangent' at times. He took the supplements for about three months and although quite sceptical at first, I did notice a difference and both teacher and tutor commented on the improvement.
I don't know how much of the improvement was down to the omega or how much to attribute to him realising he needed to 'pull his finger out'!
A friend who is also a tutor is convinced that it helps children with concentration difficulties. She also has a thing about E numbers. I really am not sure what I think but it certainly did him no harm. Happily he managed to pull it off on the day and passed!