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Autonomic Laboratory

The autonomic laboratory performs tests to measure how organs in the body that are controlled by the autonomic nerves respond to stimulation. The data collected during testing will indicate if the autonomic nervous system is functioning normally, or if damage to autonomic nerves has occurred.

The autonomic system manages essential functions such as blood pressure, blood flow, and sweating. Autonomic tests are conducted to see if the autonomic nervous system is functioning normally. The Maryland Autonomic laboratory performs detailed testing to find out if patients have autonomic nerve disease, of to determine if passing out is due to a problem with the autonomic system.

To see if a disease is affecting the autonomic nervous system, tests are performed to monitor blood pressure, blood flow, heart rate, and sweat responses. By measuring these functions, it is possible to determine if the autonomic nervous system is functioning normally.

Tests to measure blood pressure and heart rate include:

  • A deep breathing test to assess the patient’s heart response to breathing. The deep breathing test requires the patient to take deep breaths for several minutes.
  • the Valsalva maneuver. The Valsalva maneuver requires that the patient blow into a tube to increase pressure in the chest. During the testing, blood pressure and heart rate are monitored and changes are measured.
  • A tilt table test requires that the patient lie on a table that is then raised for at least 5 minutes. During the testing, blood pressure and heart rate are monitored and changes are measured.
  • The Quantitative Sudomotor Axon Reflex Test (QSART) is another autonomic test performed to measure sweating and skin temperature. Acetylcholine and a small electric current is applied to the skin. The production of sweat is measured in the lower and upper limb.

All testing is non-invasive and usually painless.

Biopsies

Skin Biopsy

A skin biopsy is an outpatient procedure that takes about 30 minutes. Your health care provider may recommend this procedure to further understand your neuropathy. This procedure is performed by a trained professional.

What to expect:

  • During this procedure the site of your biopsy will be numbed with a local anesthetic.
  • A small piece of skin, no bigger then the tip of a ball point pen, is taken from just above the ankle and just above the knee. A bandage is applied and the sample is sent to a lab for further processing.
  • After your procedure you may return to normal activities, but should keep the area clean and dry. This test provides the health care provider with information about the small nerves in your skin.

Nerve Biopsy

  • Sometimes a piece of nerve tissue needs to be examined to understand your neuropathy better. The sural nerve is usually used because of its location and minimal side effects.
  • This is an outpatient procedure and you are given medication to numb the area and make you sleepy. The sural nerve is located by your ankle. An incision is made and a small piece of nerve is removed.
  • The nerve is then sent to the lab for further processing. After the biopsy, you will have a small patch of permanent numbness where the nerve was removed.

Infusion Services

Your health care provider may recommend an infusion or intravenous (I.V.) medication for your neuropathy treatment.  At our Peripheral Neuropathy Center, the Department of Neurology organizes and facilitates the outpatient infusion center.

The infusion center provides patient monitoring in a calming and relaxing environment.  These infusions can be given through a small peripheral IV catheter.  Patients are encouraged to bring special music, reading material, videotapes or DVDs to enjoy while they receive their medication.  In case you forget, we have a large selection of movies at the clinic.

Nerve Conduction Study and Electromyography

Nerve conduction study/electromyography is a two-part test completed by a trained professional. Your health care provider may recommend this procedure to further understand your neuropathy.

The nerve conduction study or NCS involves the nerves in your arms and legs. A tiny pulse of electricity is sent through your arm or leg and the nerve response is captured by a computer. This test allows the heath care provider to see how fast or slow your nerves react.

Electromyography or EMG gives important information about your muscles. During this test a very small needle is inserted into a specific muscle. You may be asked to relax or contract your muscles. During this test you may hear cracks, pops or static, which is your muscle working. The muscle activity is then captured by a computer. This test allows the health care provider to identify normal and abnormal muscle function.

Neuromuscular Ultrasound

Neuromuscular ultrasound can help in better diagnosis and potentially in treatment of neurological disease. For example, the technique can be used to diagnose carpal tunnel or other nerve compressions. It can also be used to diagnose diseases of the nerve or muscle. It may help in determining the best place to perform a nerve or muscle biopsy, or perform therapeutic injections. 

 A gel will be applied to the skin and the operator will apply a probe to the skin. Testing is non-invasive and usually painless.

Quantitative Sensory Studies

Quantitative sensory studies are used to quantify sensory loss in neuropathy. They include testing vibration, cold, warmth and heat perception and are useful in diagnosing neuropathy and determining outcomes in neuropathy.

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