The Autonomic Nervous System is supplied by Sympathetic and Parasympathetic fibers and controls involuntary functions such as heart rate, blood pressure, sweating, and urinary bladder function. This important system can be impaired individually or as a part of other disorders such as diabetic neuropathy or Parkinson disease. The Nerve and Muscle Center’s laboratory is one of few in Texas that provides comprehensive evaluation of this important system. Information to patients is sent in advance because certain medications need to be held at least 2 days earlier. Detailed reports are sent to the referring physicians within a week of the testing.