Is symbol search kind of like those "Where's Waldo" books where they have to find something? If so, I could see that being highly dependent on tracking or visual perception.
My DD doesn't have any handwriting issues but she is extremely slow with written work, esp if it involves copying. Her cursive packet looks perfect but it takes her forever. I can see her bombing the coding section. We are going to have her tested. My DS scored a "10" and even though his handwriting and fine motor is terrible, he probably rushed through it and therefore was able to do ok (it was still his lowest score, though).
