" folded across his chest, Klein was sitting on the edge of his desk. “Well, the EEG would have proved that she had it,” he said, “but the lack of dysrhythmia doesn’t prove to me conclusively that she doesn’t. It might be hysteria, but the pattern before and after her convulsion was much too striking.” Chris furrowed her brow. “You know, you keep on saying that, Doc—‘convulsion. "

― William Peter Blatty , The Exorcist