My DS1 used to do this....the first time when he was 14mths old. Scared me to death, and friends and family as they witnessed it too. he tantrumed, held his breath, went blue then passed out (just because I walked away to get his sister and dared to leave him with his aunty!). THEN he started breathing again (which is what they do...)
It took me a while, but he was aware that he was getting his own way thro it as I was too scared to induce an attack, and my HV kindly suggested next time just walking away and leave the room.
God, that was sooooo hard.:(
I did it tho (he was nearly four by then, so very aware of the reactions he was getting) and I was worn down by it all, as was nursery too.
I hurd a thud, waited, then he came round screaming in terror as mummy wasn't there, as I normally would have been. I rushed in holding him to calm him but didn't apologize for leaving him, just told him that this came from his tantrum and that he was to stop. (I know I sound harsh, but I was at the end of my tether completely, especially with other stuff going on in the family anyway)
He never once did it again!
I am not saying at all that this is the advice to take now, at the age of 17mths, but when you find yourself reacting to her her, she is obviously bright enough, even now, to know that she is getting a reaction. (my son is very bright. from others I have spoken too, it seems to be the brighter kiddies doing this thro sheer frustration. I may be wrong, I only state in my experience.:))
All I am saying is....you aren't alone in this. After this happened it transpired that this is what my DH's brother did too as a child, and he too was a bright child and frustrated of his limitations. MIL had forgotten how she had dealt with it tho, just that he had grown out of it by the time he started school.
I am sure that there must be advice out there on the intrnet tho, I just am clueless on how to look up and post links.
feel for you tho, as they are scary little monsters sometimes aren't they
!!