Hi, I also suffer from Hemiplegic Migraines and have done now since I was 7, I am now 31. I experience an attack every 6 to 8 weeks and at their worst will last for 12 days.
I am currently taking Flunnarizine, which is a calcium channel blocker. Although it has reduced the severity of my attacks I continue to suffer from them on a regular basis, and side-effects. I have tried all the preventative medications available, including Verapamil (which is also a calcium channel blocker) but this caused me to develop an extremely stiff neck (to the extent the GP at uni thought I had meningitis). Although I knew it was my migraine trying to get out, so what I ended up having to do was stop the medication the next day and then I would have my hemiplegic migraine. So in the end i decided it wasn't worth using it.
I have tried to survive without preventative medications, but the attacks are just too severe. I am also unable to find any triggers for my attacks. Also I suffer from chronic daily headaches and I am now under a specialist in London, and he really seems to think he will be able to help me.
It is my left side that is affected, as well as my speech. And I go completely off the planet!!!
I hope you find a preventative medication that helps you.