Somatosensory evoked potentials (SSEP)

This leaflet is designed to give you some information about the investigation for which you been referred. We hope it reassures you. We have a team experienced in these investigations and you will have the chance to discuss further questions or concerns before the start of the investigation.

Consent

We must obtain your consent for any procedure or treatment beforehand. Staff will explain all the risks and benefits before they ask for your consent. If you are unsure about any aspect of the procedure or treatment proposed, please do not hesitate to ask them for more information.

About somatosensory evoked potential (SSEP)

A SSEP measures the function of the sensory pathway. The test can record waveforms from your nerves by placing small discs and stickers (called electrodes) on the surface of your skin. This assesses the ability of your nerves in the hands and feet to pass a signal through to your spinal cord and up to your brain.

What is the reason for the test?

There are many reasons for having a SSEP. You may have tingling, numbness or change in sensation in your arms and legs, and the waves recorded in a SSEP can help your medical team understand how well your nerves and spinal cord are functioning. Sometimes, the test can provide surgeons with useful information about sensory pathways before surgery that you might have been booked for.

Please fill in the patient screening form if you are attending the SSEP prior to spinal cord surgery for scoliosis correction.

Where will the EEG be performed?

Neurophysiology have two departments. One of these can be found on level 3 of the main Outpatients building and the other is located in Clinic 33 of the Addenbrooke’s Treatment Centre (ATC). Please check your letter carefully for details on where your appointment will be and use the maps (below) to guide you. There is additional information on our website about getting to Addenbrooke’s and different modes of transport.

Please note: if you arrive more than 30 minutes late for your appointment, you may not be seen.

Please contact us if you are travelling via hospital transport as this may determine the time of your appointment. Unfortunately, we are unable to see patients on beds or on stretchers in our outpatient department; please call us if this affects you.

Who will be present?

There will be one or two clinical healthcare scientists present performing the test. If you would feel more comfortable with a healthcare scientist of a particular gender or would like an chaperone please let us know. It is possible to bring someone with you if you wish.

Addenbrooke’s is a teaching hospital and you may be asked if you would consent to trainee staff performing the test under supervision or if you would mind other healthcare professionals/students observing the test. Refusing consent for this will not affect your test.

We have no provision for accompanying children to be supervised whilst you are having this investigation.

What happens during the test?

The healthcare scientist will explain about the test and give you the opportunity to ask any questions you might have. You should expect to be in the department for approximately one hour.

A healthcare scientist will measure your head using a soft pencil, like a crayon, and a tape measure. They will then use a cotton bud and gritty paste, like an exfoliator, to clean small areas of the scalp. This is not painful, but does involve some rubbing. Small silver discs with wires on will then be attached to your scalp using a special sticky paste. Sticker electrodes will also be placed on your neck, shoulders, back and knees.

We will test one arm or leg at a time. A small stimulator will be placed at your wrist or ankle and will give a small electrical pulse which will feel like a tapping/tingling sensation. This might make your thumb or big toe twitch slightly. The test will be repeated several times on each hand and foot to check that the responses we get are the same each time.

You will be given pillows to make you comfortable and be asked to relax as much as possible, often with your eyes closed. It is important that you try to relax during the test because the signals we are looking for are very small and can be difficult to see if you are tense.

What happens after the test?

The healthcare scientist will remove the electrodes and clean your skin and hair. If you have no other appointments at the hospital, you will be free to return home to your normal activities.

When do I get the results?

The results will not be available on the day of the recording. The healthcare scientist and doctor will review the test and prepare a detailed report for the consultant that referred you. The results will be sent to your conferring consultant within two weeks. It is best to discuss these results with the consultant that referred you as they will need to be explained alongside any other tests that have been performed.

Risks

Occasionally there can be slight redness or skin irritation where the electrodes have been attached. This usually gets better by itself. Please inform the healthcare scientist if you have any skin conditions, sensitive skin or any allergies.

Contacts/further information

If you need any further information or have any other queries please contact the neurophysiology administrator on 01223 217136 Monday to Friday 08:30 (8:30am) to 17:00 (5pm) or by email.

Appointment locations

If your appointment is in Clinical Neurophysiology in the main Outpatients building

We are between Ward A3 and the Ultrasound Department on level 3 in the Outpatients building.

If your appointment is in Clinic 33 – ATC

We are on level 3 in the ATC, at the end of the corridor, just before the double doors to Papworth Hospital. You will find us next to the Endoscopy Department.

MyChart

We would encourage you to sign up for MyChart. This is the electronic patient portal at Cambridge University Hospitals that enables patients to securely access parts of their health record held within the hospital’s electronic patient record system (Epic). It is available via your home computer or mobile device. More information is available on our website.