I don't know much about cerebral palsy, but I too have had epilepsy since I was two. The important thing to remember is that it is not a death sentence, and even has it's upsides. My brain adapted to scarring on the right hand side by making my left hemisphere operate more efficiently, making me more able to complete verbal problems (such as spelling, remembering names etc). Today I am a print journalist, something that would have been impossible without my epilepsy.
Having epilepsy at an early age gives the brain plenty of time to adapt.
As for swallowing the tablets, well, I also had traumas as a child, considering I was taking Dialantin, which at that time only came in huge capsules. I had problems swallowing them at first, but eventually I got used to taking them. In relation to Topomax, that stuff does taste disgusting. I would not put it on ice-cream. Maybe adding it to something that is not sweet would be better, such as a curry, as it has a bitter taste. I understand that Topomax is generally used in conjunction with Lamictal because it increases the strength of the Lamictal. If your grand daughter has no problems with Lamictal (which tastes delightfully like black currant) maybe you can speak to her doctor about increasing her dosage of Lamictal and taking her off the Topomax. If you are new to learning about epilepsy, you will see that there are dozens of drugs available, and many options is some of them aren't suitable.