I read that girls tend to be more accommodating in class/flexible in general - and therefore their ADHD or ADD often goes undiagnosed. DS6 was just curious and the type to climb up to look in the fish tank you know - when he was nearly 3 and in Montessori . The other kids some of them younger - were content to put their hands in the un-cooked pasta, and just weren't as lively!! I think its important to check for ADHD - but being the world's biggest skeptic due to all the "epidemic" of it - I still say find someone that monitors brainwaves QEEG I think it is - don't just go by observation. Even now, DS6 displays characteristics of ADHD and ODD that are so similar to gifted that without QEEG I'd really wonder about misdiangosis and to some degree I still do. You can find comparative lists on About.com.
We are going to try and use Biofeedback if we can figure out how to afford it. Ultimately, I don't think our insurance covers ADHD drugs anyway, and then again, insurance assumes you will always have a job and insurance - which in these hard times -isn't certain. Biofeedback can improve it/cure it almost I think. Drugs are going to mask it, and possibly lead to permanent damage in other areas - which I just think for a potentially gifted kid is really not a great route to go - though really for even a non-gifted kid - it's not a greate route to go.
To answer the earlier question about has there been a decline as child got older in attention? Hard to say. I think the biggest change was the manifesting ODD behavior in school situations and the harder line he takes back talking at home when unhappy. He is able to focus on anything that interests him for hours (but there is such a thing as over focused ADHD if you read Daniel Amen's book). His impatience level of wanting everything "now" has always been there.
