ANS/VNG Testing

The autonomic nervous system (ANS) is the part of the nervous system that controls:

  • Blood Pressure & Pulse Rate
  • Blood Flow to Different Parts of the Body
  • Sweating
  • Bowel & Bladder Function
  • Sexual Function

ANS testing is comprised of 4 individual tests, each one measuring a different aspect of the ANS. All 4 are usually performed in one 90-minute session and are safe and non-invasive.

  • Sweat Test – A machine is used to stimulate the sweat glands and measures sweat production (you may feel a slight local burning or tingling during this test)
  • Heart Rate during Deep Breathing (HRDB) Test – You will be asked to breath deeply and steadily at a rate of 6 breaths per minutes during this test
  • Valsalva Test – For this test, you blow into a plastic tube for 15 seconds hard enough to produce a pressure of 40mm/Hg to test your blood pressure and heart rate response

The VNG portion of the exam tests for dizziness and balance by assessing the vestibular and neurological functions of the body.

Are there medications I should avoid before testing?

There are a number of medications that, with your practitioner’s permission, should be discontinued 12-24 hours before the test, including:

  • Common cold remedies
  • Drugs for pain
  • Promatine & Fludrocortisone

Are there other special preparations?

  • Avoid alcohol, caffeine or nicotine for 12 hours prior to the test
  • Wear soft, non-restrictive clothing. Avoid clothing that may restrict blood flow and remove elastic stockings
  • Avoid clothing that may restrict blood flow and remove elastic stockings
  • Avoid stress – Your results will be more accurate if you are rested and relaxed
  • Arrive early
  • Evacuate your bladder and preferably bowel prior to the test
  • Do not engage in discussion with the person administering your test because it could affect your results