Please help!

I am hoping someone can help my family figure out what is going on with our 4.5 year old daughter. She started having eye twitches at age 1. She gets a strange look on her face and then her right eye starts twitching. For most of the year she is fine- maybe 1 or 2 a day but then in November/December she goes through 6 weeks or so with thousands a day. It prevents her from sleeping and basically having a normal life. She is always conscious during these events and answers questions (although she will whisper back). When it is really bad, she clenches her fists and her lip also twitches a bit.
She has been diagnosed with epilepsy, had many EEG's (which show nothing) and has taken Keppra, which hasn't worked. Any ideas why it is only this time of year? Has anyone had similar episodes?
Any feedback would be helpful.