Well, I've had this abnormal condition since I was a child (don't remember when). I' m 17 now. I am able to imagine/daydream (if that is what it really is?), and when I do, my hands jitter/ randomly move. I am able to control imagining/daydreaming, and these things usually are about some plot continuation of a TV show or some sort of junk like that. It's like watching a TV show that I just created in my head... (I know, wierd). What is really odd is that, I can picture what I daydream, and while I do this, my hands start moving. Is this some brain to hand connection that triggers movement when I "imagine stuff"? I'd like to know more about this.
I've always assumed this was nothing until recently when I realized that this could be something new, since I could find absolutely no trace of this on the web. It's not a negative condition or anything, I imagine on my own free will, and it is limited to once or twice a day, or sometimes none at all.