Neurology Clinic: Autonomic Testing
Autonomic tests measure how the systems 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 as it should, or if nerve damage has occurred.
What is Autonomic Testing?
The nervous system has three parts: motor, sensory and autonomic. The autonomic system manages all internal functions such as blood pressure, blood flow, and sweating. Autonomic tests are conducted to see if the autonomic nervous system is functioning normally.
The autonomic nervous system can be affected by problems involving the nerves or brain or can occur as the result of certain medications. Symptoms that can occur from problems with the autonomic nervous system include dizziness, fainting, fatigue, rapid heart rate, problems with digestion, abnormal sweating, and impaired sexual functioning. In addition, sometimes patients with numbness and burning in their hands or feet might experience ANS problems (this is because the same type of small nerves that operate the ANS also play a role in sensation).
How is Autonomic Testing performed?
To see if a disease is affecting the autonomic nervous system, several tests are done to monitor blood pressure, blood flow, heart rate, and sweating. By measuring these functions, it is possible to discover whether or not the autonomic nervous system is functioning normally. At Phoenix Neurological, we use the Quantitative Sudomotor Autonomic Reflex Test (QSART), which measures sweating and skin temperature.
Quantitative Sudomotor Autonomic Reflex Test (QSART)
QSART is used to diagnose:
Painful, small fiber neuropathy when nerve conduction test results are normal
Disturbances of the autonomic nervous system, which controls the sweat glands, heart, digestive system, other organs, and blood pressure
Complex pain disorders
How is QSART performed?
The test has three parts and measures resting skin temperature, resting sweat output, and stimulated sweat output. Measurements are typically taken on arms, legs or both. A small plastic cup is placed on the skin and the temperature and amounts of sweat under the skin are measured. To stimulate sweat a chemical is delivered electrically through the skin to a sweat gland, but the patient will only feel warmth. A computer is used to analyze the data to determine how well the nerves and sweat glands are functioning.
How will it feel?
The patient will experience little or no discomfort, but the test could take two or three hours to complete.