There are many other functions that we do not yet understand. Your doctor wishes to determine whether your autonomic nervous system is functioning normally. Certain diseases can attack the autonomic nervous system in isolation, or as part of a more widespread illness. In all of these cases, the autonomic nervous system will be functioning poorly or not at all. In contrast, when pain restricted to one part of the body is the main problem, your doctor will wish to determine if the autonomic nervous system on that side is functioning too much.
Testing depends on the problem.
You are then raised to the upright position for 20 minutes, and taken back down again. This is called the tilt table test . This is called the deep breathing test . This is called the Valsalva manuever . The orange powder turns purple where you sweat, telling us which parts of the autonomic nervous system are working, and which are not.