I believe DS4 does have some sort of learning disability ... I can already tell he's getting his letters mixed up and while he's great with math, when it's math on paper (or when he sees numbers) he sometimes transposes digits and such.
IMHO, those transpositions and reversals sound age-appropriate - even the ones where he swaps syllables of spoken words.
It's true that all of this is age-appropriate and that's why it's often really tough to recognize LDs in kids who are this age. I can remember everyone under the sun telling us that when our ds reversed letters, switched #s etc it was all age-appropriate... and I can even remember several teachers telling us the reason he resisted writing was "he's a boy". Since our ds wasn't evaluated for LDs until he was in 2nd grade, I really don't know what a neuropsych for instance could determine at 4 re whether or not there is a disability... but I do think a mom's instinct when she has a gut feeling that something is up is worth investigating.
polarbear
