K.A.
Each of my kids went through a period of waking hysterical about about or around 2 years of age. I assumed it was a bad dream since I could not find any other logical reason for it. My daughter seemed to quit waking hysterical when I started playing a kids music cd in her room with it set to play constant all night. I think maybe it helped to distract her thoughts.
I can remember having nightmares as a kid. I think what was most upsetting was not being about to clear it from my thoughts when I awoke and finding that every time I closed my eyes that it was there again. That is why I think playing a kids music cd in her room might help calm her and distract her thoughts when she awakes from a nightmare. It seemed to work for my daughter and it might be worth the try.