Autonomic Testing

Autonomic testing, also known as autonomic nervous system (ANS) testing, is a series of tests used to evaluate the function of the autonomic nervous system. The ANS is responsible for controlling involuntary functions of the body, such as heart rate, blood pressure, digestion, and breathing.

Purpose of Autonomic Testing

The purpose of autonomic testing is to diagnose and monitor disorders of the autonomic nervous system, such as:

• Autonomic dysfunction
• Orthostatic intolerance
• Postural orthostatic tachycardia syndrome (POTS)
• Autonomic neuropathy
• Multiple system atrophy
• Pure autonomic failure

Types of Autonomic Tests

There are several types of autonomic tests, including:

• Heart Rate Variability (HRV) Test: measures the variation in time between heartbeats to assess the function of the sympathetic and parasympathetic nervous systems.
• Blood Pressure Response to Standing: measures the change in blood pressure when standing up from a lying down position to assess orthostatic tolerance.
• Tilt Table Test: measures the heart rate and blood pressure response to changes in posture, typically using a tilt table that slowly tilts the patient from a horizontal to a vertical position.
• Quantitative Sudomotor Axon Reflex Test (QSART): measures the function of the sympathetic nervous system by assessing sweat production in response to a stimulus.
• Thermoregulatory Sweat Test: measures the ability of the body to regulate temperature through sweating.

How Autonomic Testing is Performed

Autonomic testing is typically performed in a specialized laboratory or clinic by a trained healthcare professional. The tests are usually non-invasive and painless, but may require some preparation, such as:

• Avoiding certain medications that can affect the results of the test
• Fasting for a period of time before the test
• Wearing comfortable clothing and avoiding tight clothing that can restrict movement

Interpretation of Autonomic Test Results

The results of autonomic testing are interpreted by a healthcare professional, typically a neurologist or cardiologist, who will review the data to determine if there is any abnormality in the function of the autonomic nervous system. The results may indicate:

• Normal autonomic function
• Mild, moderate, or severe autonomic dysfunction
• Specific patterns of autonomic dysfunction that can help guide treatment and management.

Limits of Autonomic Testing

Autonomic testing has limitations, including:

• May not detect all types of autonomic dysfunction
• May require repeated testing to confirm results
• May be influenced by various factors, such as medications, sleep deprivation, and emotional state.

Frequently Asked Questions (FAQs)

What is autonomic testing?
Evaluation of the autonomic nervous system.

Why is autonomic testing done?
To diagnose autonomic nervous system disorders.

What does the test measure?
Heart rate and blood pressure responses.

Is autonomic testing painful?
No, it is generally painless.

How long does the test take?
Typically 1-2 hours.

Do I need to prepare for the test?
Yes, avoid caffeine and tobacco beforehand.

Can I take my medications before the test?
Check with your doctor for specific instructions.

What are common tests included in autonomic testing?
Tilt table test, heart rate variability test.

Can children undergo autonomic testing?
Yes, but may require special considerations.