Hi gaffers/helentheresa, I'm presuming you are the same poster.
My DD1 had a series of 'drop attacks' - episodes where she crumpled to the floor for no obvious reason. The first few were dismissed as tripping/falling over something that they couldn't identify, as she has ataxia so wobbly at the best of times, and a virus by the GP. One day she fell while standing at the playdough table, then twice on the walk home holding my hand, so I knew it was a vertical drop, not pitching forward, IYSWIM.
We were fast-tracked to the hospital, saw a consultant, had an EEG and had an epilepsy dx on the strength of a verbal report. No meds. But then the written report came through, and the consultant phoned to ask us to come in and discuss meds.
DD1 started SV in January 2009 and has been on it ever since. She hasn't had a drop attack since December 2009, but has had tremor and absences. She has tried clobazam (Became drowsy, unco-ordinated, unable to interact), ethosuximide (Huge hives and rash, emotionally disturbed), and lamotrigine (just weaning off because of tremor and malco-ordination) in conjunction with the SV, but had to stop them all.
SV is the only one that she has had no symptoms from.
I don't know what the stats on CP and epilepsy are, but I do know that because my DD has a brain malformation, her consultant is very keen to max out whatever med she is on, because if seizures establish they are likely to be harder to treat, so that is something to explore with your consultant.