17457 Seeg Test

Overview

SEEG stands for stereoelectroencephalography (say: stair-ee-oh-eh-lek-tro-en-sef-ah-log-raf-ee). It is a test that records the electrical activity inside your brain. Small, thin wires called electrodes are placed, for a short time, into the area of the brain where doctors think your seizures may start. The electrodes pick up the brain's signals, and doctors watch the recordings over several days. It is mostly used for people with epilepsy whose seizures are not controlled by medicine and who are being checked to see if surgery or another treatment could help. The number in the title (17457) is just a reference code used by some health services to label this test. It is not part of the medical name.

SEEG is not a common test. Most people with epilepsy never need it. It is used only in specialist epilepsy centres, for a small group of people who are being assessed for epilepsy surgery or another advanced treatment.

Symptoms

Common symptoms

• Seizures that continue even after trying two or more epilepsy medicines
• Seizures that look unusual or do not fit the pattern seen on regular tests
• A brain scan that looks normal, or does not clearly show where seizures start
• After the electrodes are placed: mild headache, tenderness or tightness around the small wounds on your scalp
• Feeling tired or a bit foggy for a day or two after the procedure
• Some people have a seizure during the recording. This is expected and can actually help the team

Symptoms in children

• Children may feel scared or upset about the head bandages and wires, so extra reassurance helps
• Younger children may need a general anaesthetic for the electrode placement and removal
• Tiredness, poor appetite or clinginess for a day or two afterwards is common
• Some children have more seizures in hospital because their usual medicine routine changes - tell the team straight away if this happens

Symptoms in older adults

• Older adults may feel more tired after the procedure and take a little longer to recover
• Other health conditions and all current medicines should be reviewed with the team before the test
• Confusion or new memory problems during the hospital stay should always be reported to staff
• A higher chance of bleeding or bruising if you take blood-thinning medicines - tell your team well in advance

Causes

Main causes

• SEEG is done because of focal epilepsy - epilepsy where seizures start in one part of the brain
• Seizures have not stopped despite trying appropriate epilepsy medicines
• Standard tests such as MRI scans and video EEG have not clearly shown where seizures begin
• The epilepsy team needs more detail before deciding whether surgery or another treatment could help

Risk factors

• Epilepsy that started in childhood or has lasted many years
• A scar, growth or structural change in the brain seen on a scan
• Seizures that are frequent or hard to control
• Being assessed at a specialist epilepsy surgery centre

When to see a doctor

See a doctor urgently if:

• Any new weakness, speech difficulty, or change in vision after the procedure
• Signs of infection around the electrode sites
• Clear fluid from the nose or ear
• A headache that keeps getting worse
• Seizures becoming more frequent or different from usual after the test

Book a routine appointment if:

• Questions about the results and what happens next
• Tiredness or poor sleep that lasts more than a couple of weeks
• Low mood, worry or anxiety about the test or about epilepsy surgery
• Advice about driving, work, school or exercise after the test
• Any concerns about your epilepsy medicines

Diagnosis

SEEG is itself part of the diagnostic journey, rather than a test for a new condition. It is offered after a full epilepsy assessment, when your team needs to know exactly where seizures start. The recordings are studied together with your scans, your seizure history and the video of your seizures, and the team then meets to agree on what the results mean for you.

Tests that may be done

• A detailed history of your seizures, ideally with videos from family or friends
• MRI brain scan using a strong scanner and a special epilepsy protocol
• Video EEG - recording brain waves from the scalp while you are in hospital
• Neuropsychology assessment - talking and memory style tests to map how your brain works
• Sometimes PET or SPECT scans, which show how different parts of the brain are working
• The SEEG recording itself, usually over several days
• Electrical stimulation through the electrodes to help map brain function (done in some cases)

What to expect at your appointment

You will usually have a planning MRI scan first. The electrode placement is done under general anaesthetic and takes a few hours. You wake up with a bandage or dressing on your head and thin wires coming from the scalp, connected to a recording machine beside your bed. You stay in a monitored room, often with a camera, so staff can see any seizures. Your epilepsy medicines may be reduced so that seizures happen during the recording. A nurse will check your wounds, your blood pressure and how you are feeling regularly. After a few days to about two weeks, the electrodes are removed, usually under a short anaesthetic or with light sedation, and you go home, often the next day. Your team will talk you through the results at a follow-up appointment.

Treatment

SEEG does not treat epilepsy itself. Its job is to give your team the information they need to plan the right treatment for you. The results may show a clear area where seizures start, which could make epilepsy surgery an option. Sometimes the results show that surgery is not the best route, and the team will then talk with you about other choices, such as different medicines or implanted devices that help control seizures.

Self-care at home

• Follow your team's instructions about hair washing and wound care - usually keep the scalp dry for the first few days
• Take it easy for the first week or so. Build activity back up slowly
• Keep a simple seizure diary after you go home, noting dates, times and what happened
• Get plenty of sleep - tiredness is a common seizure trigger
• Ask someone to stay with you for the first day or two at home if you can
• Ask your team before driving, swimming alone, or doing anything where a sudden seizure could be dangerous

Medical treatments

Treatment after SEEG is planned around what the recordings show and is decided together with you and your family. Options generally include: continuing or adjusting epilepsy medicines; epilepsy surgery to remove or disconnect the small area where seizures begin; implanted devices that send gentle electrical signals to the brain or to a nerve in the neck to help reduce seizures; or a special dietary approach supervised by a dietitian. Your epilepsy team will explain the benefits and risks of each option in your own case. Never change or stop epilepsy medicines on your own - this should always be done with your team.

When is surgery considered?

Epilepsy surgery may be offered if the SEEG shows that seizures start in one small area of the brain that can be safely reached, and if tests show that removing or disconnecting that area is unlikely to cause lasting problems with movement, speech, memory or thinking. The decision is made by a team of specialists and is always discussed with you in detail, including the possible benefits and risks.

Living with this condition

Most people return to their usual routine within one to two weeks of the test. You may have small scabs or tiny marks where the electrodes went in, which usually heal well. Some people feel more tired than expected for a while, and it can take a little time to feel like yourself again. Keep taking your epilepsy medicines exactly as prescribed, and keep your follow-up appointments.

Lifestyle tips

• Keep a regular sleep pattern - late nights are a common trigger for seizures
• Limit or avoid alcohol, as advised by your epilepsy team
• Tell close family and friends what to do if you have a seizure
• Carry any seizure first-aid information your team gives you
• Be open with your employer or school about what you need - simple adjustments often help a lot
• Check your local rules about driving with epilepsy before getting back behind the wheel

Diet and exercise

Gentle walking and light activity are fine once you feel ready, usually after a few days. Wait until your team says it is safe before swimming, cycling, climbing or contact sports, because a seizure in these situations can be dangerous. Eating regular meals and drinking enough water helps you feel steadier. If your team suggests a special medical diet for epilepsy, it should only be done with a dietitian's support.

Mental health and emotional wellbeing

It is very common to feel anxious, low or worn out before and after a test like this. Being wired up in hospital for days can feel strange and frustrating, and waiting for results can be hard. Feeling like this does not mean anything is wrong with you. Talk to your team - they are used to these feelings and can arrange extra support. If you ever have thoughts of harming yourself, or feel you cannot cope, contact your local emergency number or a crisis support service straight away, or tell a member of your care team immediately.

Prevention

The epilepsy that leads to a SEEG test usually cannot be prevented, and the test itself cannot be prevented - it is a planned part of your assessment. What you can do is lower the small risks that come with the procedure by following your team's instructions carefully, telling them about all your medicines (especially blood thinners), and reporting any new symptoms quickly.

Screening programmes

There is no general screening programme for this. If you have epilepsy that is not controlled by medicines, ask your epilepsy team whether a referral to a specialist epilepsy surgery centre would be appropriate for you.

Complications

If left untreated

• Without knowing where seizures start, it is harder to plan surgery or other treatments that could reduce seizures
• Seizures may keep happening, which can affect safety, work, study and independence
• Repeated seizures can affect memory, mood and confidence over time
• There are small risks of injury during seizures, including falls

Long-term outlook

For many people, SEEG gives the clarity that opens the door to treatment that genuinely reduces seizures - sometimes to the point of being seizure-free. For others, it helps rule out options that would not have helped and points towards a better plan. Either way, you end up knowing more than you did before. Serious complications from the procedure are uncommon, and specialist teams are well practised at spotting and managing them early. Whatever the results, your team will keep working with you on the next step.

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