If you've been taking Topamax for close to a year and it's not been effective, I'm wondering why your doctor didn't discontinue it before trying the Keppra.

Now (if it works) he/you won't know if it's the combination or just the Keppra that's helping, and you might be continuing to take the Topamax needlessly.
I'm admittedly not a fan of Topamax, but I'm even more against taking medications that are unwarranted.
Doc