What device monitors muscle tension to help individuals recognize and reduce tension?

The correct answer is the electromyograph, which is a device specifically designed to measure and monitor muscle tension. It works by detecting the electrical activity generated by muscle fibers when they contract. This information is valuable in recognizing areas of excess tension in the body, which can often be linked to stress or anxiety. By providing feedback on muscle activity, individuals can learn to identify and reduce tension through relaxation techniques or biofeedback training.

In contrast, other devices serve different purposes; for instance, the polysomnograph is used to monitor sleep patterns, the thermograph measures temperature changes in the body, and the electrocardiogram tracks heart electrical activity. Each of these devices is beneficial in its own context, but none are specifically tailored for monitoring and addressing muscle tension like the electromyograph.