Autonomic Function Test (AFT)

The autonomic nervous system regulates important body functions such as blood pressure, heart rate, breathing and perspiration. An Autonomic Function Test (AFT) evaluates the integrity of these functions.

AFT may be used to assess neurological conditions with autonomic involvement (e.g. peripheral neuropathy, autonomic neuropathies, parkinsonian syndromes) and evaluate symptoms including dizziness, fainting spells, abnormal sweating and imbalance. 

How should I prepare for the test?

• Continue with your regular diet and medications as instructed by your doctor.
• Bring a list of all medications you are taking, including the dosage. Please inform the neuro electrophysiologist before the test.
• Wear comfortable, loose-fitting clothing such as a loose shirt, blouse, shorts or bermuda shorts.
• Avoid applying creams, lotions, powder or oils on your limbs on the day of the test.
• Contact us at ​6330 6363 if you have an implanted electronic device such as:
  • Cardiac pacemaker
  • Implantable cardioverter defibrillator (ICD)
  • Neurostimulator
  • Any other implanted medical electronic device

How is the test performed?

The test is performed by a neuro electrophysiologist and typically takes about 45 to 60 minutes.

The test involves a series of procedures to evaluate blood pressure regulation, heart rate responses to certain manoeuvres and sweat production in response to stimulation.

• A cuff will be attached to your finger to monitor blood pressure continuously.
• Electrodes will be placed on your chest to record your heart rhythm.
• Blood pressure and heart rate will be monitored throughout the test.
• You will be guided through a series of manoeuvres, which include:
  • Head-up tilt
  • Deep breathing
  • Valsalva manoeuvre (forcefully blowing air out) 
• For sweat output measurement, small capsules are placed on your skin, usually at the arms and legs. A mild electrical current is used to deliver a medication (acetylcholine – a naturally occurring neurotransmitter) that stimulates the sweat glands. The amount of sweat produced is then measured.
• Once the test is completed, all monitoring equipment will be removed, and you may return home.

A detailed report will be reviewed by your doctor, who will discuss the results with you at your follow-up appointment.

Frequently Asked Questions

Is the test safe?

Yes. Autonomic Function Testing is generally safe and well tolerated. The neuro electrophysiologist will guide you through the components of the test.

Your blood pressure will be monitored continuously using a finger cuff. While the cuff is in use, your finger may feel tight or numb, and the skin colour may temporarily change. These effects are usually short-lived and resolve once the cuff is removed.

During sweat measurement, you will experience a warm, tingling and prickling sensation as a small amount of acetylcholine and mild electrical stimulation are applied to the skin. These effects are expected and temporary and usually resolve quickly after the test.

The neuro electrophysiologist will monitor you throughout the procedure and ensure that the test is performed safely.

After sweat measurement, some redness or itching may occur at the test sites and usually resolves within a few hours. Rarely, skin irritation may develop.

Can I undergo the test if I am feeling unwell?

No. If you are feeling unwell e.g. fever, cough, do not proceed with the test. Call to reschedule your appointment.

Have questions or concerns? Call:

Tel: 6330 6363

Office Hours:
8.00am – 5.30pm, Mon – Wed, Fri
8.00am – 5.00pm, Thurs
Closed on Sat, Sun, Public Holidays

Click here for directions to:

• Neurodiagnostic Laboratory at NNI@TTSH

The information is correct as of October 2026 and subject to revisions without notice.