After Jana (the daughter) finishes banging her fist on the staircase handrail, a shadow moves behind her. As it moves, it appears to be an arm shadow, but not from Jana.
As Jana and her father are arguing in the study, the camera cuts to a shot of Mrs. Loren sitting in an overstuffed chair watching them. At that moment a shadow passes across her body; it's either a crew member of a piece of equipment - possibly a camera - since there are only two other characters in the scene and neither of them are near Mrs. Loren.
It seems unlikely that Jane would never have noticed before that she never felt pain.