Aloha Rosa,
Well, I won't jump in there with a judgment on whether your experience was a seizure or not.
However, you're not alone with having a body part may jerk or shake, etc. during a mediation or exercise. Chunyi has just said to thank it and allow the Qi to work though and heal the channels.
Chunyi mentions that when Qi works its way through channels that have been close for some time, or those of a more physical/structural nature, there can be various physical sensations - or not.
For example: one of the participants from this Forum shared about feeling "pushed" in the back during one of the mediations at the 2005 6-day retreat. After that, she found her spine and posture to be straightened out.
Much Love, Shawn
