Body language is so fascinating, even though lately it's going a bit TV pseudoscience a lot of the time with people trying to pretend that it's much more scientific/objective/defined than it is, calling themselves "experts" in it, etc. However, we all read body language and could probably identify many of the same gestures and expressions that do mean the same things to us. At the same time, we recognize that body language is also unique to the individual to some degree, for example, we know that a particular gesture by one person indicates evasiveness but might not for someone else, etc, and a lot of body language even down to facial expressions is influenced by culture and so on.
In this case, some of the body language that has really jumped out at me has been Casey's eye movements and compulsive hand movements.
The irises of her eyes are in almost constant motion. When she's talking to someone her eyes are usually continually jumping back and forth, right and left. I tried doing this and it's really hard to do, it's actually hard to focus when you do it.
Also, she has compulsive rituals she does with her hands. She has one where she traces around each fingernail with the tip of her thumb, starting at the pinkie and working her way fingertip by fingertip up to the index finger, then index finger circles around the thumbnail, then finally brushes her fingertips together like getting rid of lint or something, and then repeating. She also picks at her fingernails compulsively and even goes as far to pick at the lines on the palms of her hands, quite hard.