“People with borderline personality disorder have a very difficult time identifying when distress is very high,” said Lynn McFarr, director of the cognitive and dialectical behavior therapy clinic at Harbor U.C.L.A. Medical Center, which provides care for people in the Los Angeles County system. “If we can show them, in this biofeedback fashion, that the signals went off the rails yesterday, say, after they got into a fight with a co-worker, then they’d be able to anticipate that emotion and target it with the skills they’ve learned.” You can find more about this here