Shadowdancers — Sally Odgers

This is a book for young adult girls about the complications of life for two young dancers eager to succeed
Merimba and Pirry are twins in appearance and character, living in two different worlds. Merimba is a quadriplegic whose condition has dragged her family apart. She is in a coma. Pirry is a Valourn, an acrobatic dancer in the land of Rargon. When Merimba flees her body a switch is made.