Hi Worried mum, I've not come across this before myself, but it certainly needs to be checked out... A GP may be able to shed light on what is happening here... This certainly needs taking seriously, so get GP on side asap... This could seriously affect your daughters ability to concentrate on her studies at school because of her sleep disruption... Another thought, has she tried sleeping in another room? Children are very receptive to things we just don't fully understand, and it maybe that a change of room to sleep in might be a good idea... Hope this helps a bit...
Wannabe