Skip to content
left end
left end
right end


Somatosensory Evoked Potential (SEP) Information 

What is a somatosensory evoked potential (SEP)?

A test that records the function of a nerve pathway between a limb and the brain by stimulating either at the wrist and or the ankle.

What should I do before the test?

Please wear comfortable loose fitting clothes.

Please wash your hair and do not use any hair products.

Take your medication as usual unless directed by your doctor.

Eat as normal.

Bring a list of your medication with you.

What will happen during the test?

  • A healthcare scientist will explain the procedure to you and answer any questions you may have. They will need to take a clinical history from you.
  • Your height will be measured
  • Your head will be measured using a tape measure and small marks drawn on with a skin pencil (this will wash off easily)
  • Electrodes (wires with small metal disks on) with be attached to your head using sticky paste or glue (these are also easily removed)
  • Other sticker electrodes will be attached to your arms ,legs, shoulders, neck or lower back depending on your symptoms.
  • You will be asked to lie down on the bed and relax
  • A small electrical pulse will be given at the wrist or ankle (depending on your symptoms) which will make your muscle twitch slightly.
  • This will be repeated on the opposite leg or arm (depending on your symptoms)
  • The healthcare scientist will remove the electrodes and wipe clean your hair with water.
  • The whole test should take under 90 minutes, this may vary depending on relaxation and cooperation.

How will I get my results?

The results will be analysed by a consultant neurophysiologist and sent back to the doctor who requested the test. This should happen within 10 working days.

Are there any risks?

If you have a pacemaker or cardiac defibrillator fitted please telephone the department before your appointment to discuss.

Contact details

To change your appointment or if you have any questions please contact the neurophysiology department on 0117 3428254

Please allow plenty of time to get to your appointment. Parking is particularly difficult. If you are more than 15 minutes late we may not be able to perform the test. If you are unable to attend your appointment please inform the department as soon as possible by calling the number above.