Biofeedback is a closed-loop feedback technique that helps individuals learn to calm the sympathetic nervous system, which can become overactive during pain.

“Things like biofeedback. In Silicon Valley where I practice, the engineers love the biofeedback. I'm an engineer by formal training, so I get it. But it's that closed loop feedback. Because remember, the brain is controlling the periphery and controlling the sympathetic nervous system. And when we're in pain, our sympathetic nervous system gets revved up. When the sympathetic nervous system gets revved up, blood vessels constrict. Heart rate goes up. Our muscles get tense. And we need sometimes ways of learning how to calm down that sympathetic nervous system.”