What is an SEP?

The Somatosensory Evoked Potential (SSEP) test checks the pathway from the nerves in the arms and legs to the brain.

A stimulating electrode is placed on your arm or leg, a pulsing stimulus is applied and causes an electrical signal to be sent to your brain. Recording electrodes are placed on your head and/or back to record this signal. The information received from these electrodes can help the doctor diagnose your problem.

Why is an SEP performed?

It is used if you are experiencing numbness anywhere, muscle weakness, or symptoms following spinal or head injury.

How is the SEP performed?

You will lie on a bed and be asked to remain very still. The test is very sensitive to movement.  A technologist will paste recording electrodes on your head, neck, back, or legs. Stimulating electrodes are also placed on your wrists or ankles. A pulsing stimulus will start in one of the stimulating electrodes as each area- left arm, left leg, right arm or right leg -  is tested.   Waveforms are produced and measured before moving on to the next area. 

Does it hurt?

No. During the test your muscles may tingle and twitch, but you will not experience any pain.

The test takes about 1 ½ hours.