Sybil's switching back to her core personality is usually signaled by her putting on her glasses.
Dr. Cornelia Wilbur:
I'm going to let you hear yourself play the piano.
Sybil: I can't play the piano anymore. I used to play. I can't play it anymore.
Dr. Cornelia Wilbur: Well, this is a part of you that calls herself Vanessa, and she can. She plays beautifully.
In the scene where Sybil and Dr. Wilbur are at the piano, Sybil begins playing With a Song in My Heart, however her hands are still on top of the piano when the music begins.
The original TV-version ran two nights for a total of four hours (198 minutes minus the commercials). Most video copies are pared down in length, one running 122 minutes and another "expanded" to 132 minutes. Both these versions are missing key scenes such as: