HI christophrighter! I think it's impressive that you were able to reduce your pain so much using Biofeedback! Since the parasympathetic and sympathetic nervous systems are both part of the autonomic nervous system (ANS), I think it makes sense that it may be harder to control those systems. Since they are basically designed to run on "autopilot" (for lack of a better term), without any thought on our part, they may be less open to suggestive thought. However, studies have shown that meditation can have an affect on the ANS, so it IS possible. Since Biofeedback was fairly successful for you, you may want to discuss other alternative pain relief methods with your physician (like meditation/relaxation). Here are some other potential mind/body treatments you may be interested in -- https://multiplesclerosis.net/natural-remedies/yoga-meditation-other-mind-body-options/. As to your original question, I think there are a plethora of symptoms that indicate issues with the CNS, including pain, dizziness, muscle weakness, unexplained fatigue, etc. If your question was more of wondering why Biofeedback seemed to work more on your CNS than your ANS, I think I already touched on that a bit. Also, here is some basic information on the differences between the parasympathetic and the sympathetic nervous systems that I thought you might find interesting -- https://www.diffen.com/difference/Parasympathetic_nervous_system_vs_Sympathetic_nervous_system. You may find it too basic, but I wanted to share it, just in case. Thanks for reaching out! Best, Erin, MultipleSclerosis.net Team Member.