Bart is right about singing the parts. I'm studying with a tremendous teacher in Seattle, and he gives me these viciously simple syncopation exercises. After listening to me struggle, he makes me sing the hihat part while playing with the other 3 limbs. Then sing the bass drum. etcetera.
Once I can sing it, I can invariably play it.
It's also an amazing demonstration that the speech center of your brain is different than your arm and leg control. There are patterns I can play easily. But when I try to speak the bass drum while playing the other parts I get tied up into knots.
Yes, my teacher uses the same method as well, "singing" the parts if some stuff isnt working out as planned.....he uses it to bug me as well, singing stupid children songs while im doing my bars, just trying to catch me offguard