Hi larseng,
Welcome to the forum! I'm so sorry to hear that you and your sister both have sz. I've had sz. both absence (petit mal ), complex partial and simple partial sz. for 41 yrs. and stress and lack of sleep are the 2 main things that can trigger a sz. They type of sz. your described sounds like a absence (petit mal) sz or a complex partial sz. If I may ask did you see any colors in your eyes or get a nervous feeling in your stomach and then blank out? If you did this was a simple partial also known as an aura sz. leading to complex partial sz.
I tried keppra and it didn't work well for me it increased my sz. and also made me very moody. To find the right sz. med (AED) ask your neuro to do a DNA test on you by doing this test they will be able to find the best med for you with the least side effects. All they have to do is wipe the inside of your mouth (on the side) with a q-tip and take a couple of tubes of blood. They can then match up the ezymes and chemicals in your body with the best AED's with the least side effects. Also you can start taking vitamin B12 1000 mcg. once a day and this will calm a persons nerves and help reduce sz.

Start keeping track of any of your sz. write down what time the sz. happened along with a description of the sz. be sure to write down when you start and stop your cycle each month because often hormones changing can trigger a sz. for many women. The main causes of epilepsy are: drug & alcohol abuse, genetics, trauma, lack of oxygen or difficulty at birth, head injury, or a bad scare. This is what my Epileptologist and neurosurgeon have told me. I wish you the best of luck and May God Bless You!

Sue