A seizure is a sudden change in electrical activity between the nerve cells, or neurons, in your brain. This can cause symptoms like twitching or unconsciousness.
If the seizures repeatedly occur, it’s called epilepsy. There are many types of seizures and epilepsies. Each type is best treated by different therapies, so it’s important to get a proper diagnosis so you can start the right treatment.
Read on to learn more about how epilepsy is diagnosed. We’ll explain the tests and techniques doctors use to diagnose the condition.
If you think you’ve had a seizure, you’ll need to see several medical professionals.
First, visit a primary care physician. They will assess your symptoms and rule out other possible causes for your seizures.
If your primary care physician suspects you had a seizure, they’ll refer you to a neurologist. A neurologist is a doctor who diagnoses and treats brain diseases like epilepsy.
Your neurologist will then use various tests to determine if you have epilepsy.
There’s no single test for diagnosing epilepsy. Your doctor will use a combination of the following tests:
Neurological exam
During a neurological exam, a neurologist will ask questions about your symptoms and medical history. This may include questions like:
- Is this your first seizure?
- When did you have the seizure?
- What were you doing when you had it?
- How did you feel before, during, and after the seizure?
- How long did the seizure last?
- Did you do anything different before having the seizure?
- Have you been ill recently?
- How long did it take to recover?
The neurologist will also examine the function of your nervous system. They’ll test your ability to:
- walk
- see images and words
- remember images and words
- talk
- balance
- move your joints or eyes
- identify different sensations, like a smell or item
Blood tests
A primary care physician or neurologist might also order blood tests. These tests can determine if another condition is causing your seizures.
This might include:
- Complete blood count. A complete blood count (CBC) test looks for markers of infection.
- Blood chemistry tests. A doctor might check for kidney malfunction, abnormal electrolyte levels, or other issues.
- Toxicology screening. This tests for toxins that might be causing seizures.
Electroencephalogram
An electroencephalogram (EEG) is commonly used to diagnose epilepsy. It uses sensors called electrodes to measure your brain’s electrical activity. The sensors are placed on your scalp.
The results of an EEG can show the activity of your brain’s neurons. It can also reveal where the seizures are happening in your brain.
An EEG is done over a few minutes or hours. But even if you have epilepsy, your EEG might be normal. This can happen if your brain activity returns to normal before getting an EEG.
In this case, you might need EEG monitoring over a few days.
Imaging tests
Imaging tests produce detailed images of your brain. They can show where the seizures are happening, which helps provide the right diagnosis.
The tests can also show tumors, scars, or structural issues associated with seizures.
Imaging tests for epilepsy include:
- Magnetic resonance imaging (MRI). An MRI scan uses radio waves and magnetic waves to create an image of your brain’s structure.
- Functional magnetic resonance imaging (fMRI). This scan shows parts of the brain responsible for memory, speech, and other functions. A doctor can use an fMRI scan to determine if your seizures affect these areas.
- Computerized tomography (CT). A CT scan uses X-rays to produce images of your brain. It can reveal abnormal lesions or structural problems.
- Single-photon emission CT (SPECT). This imaging test shows the blood flow in your brain. Generally, after a seizure, blood flow increases in the area where it occurred.
- Positron emission tomography (PET). During a PET scan, radioactive sugar is injected into the body. The scan reveals the brain’s blood flow and ability to metabolize sugar.
Neuropsychological tests
A neuropsychological exam is done by a neuropsychologist. This is a doctor who specializes in the link between brain and behavior.
The exam can help determine if seizures are affecting your psychological functions, including:
- memory
- language
- attention
- mood
- emotions
- personality
A neuropsychologist might ask questions like:
- Can you share a memory from childhood?
- Can you describe the setting of this memory? How did you feel?
- Do you experience feelings of depression, like hopelessness?
- How often do you have these feelings?
- Do you have trouble concentrating?
- Do you have difficulty thinking of words during a conversation?
They’ll also give you tests to understand how your seizures affect your behavior. These tests may be done with a computer or pencil and paper.
Epilepsies are categorized by the types of seizures they cause.
There are four main types of epilepsy:
- Focal epilepsy. Focal epilepsy causes focal seizures, which occur on one side of the brain.
- Generalized epilepsy. Generalized epilepsy causes generalized seizures, which happen on both sides of the brain.
- Combined generalized and focal epilepsy. This type of epilepsy causes both focal and generalized seizures.
- Unknown. If there isn’t enough information to determine the seizure type, it’s classified as unknown.
Since different epilepsy types require different treatment plans, it’s important to determine what type of epilepsy you have.
A doctor can do this with the following tests:
Magnetoencephalography (MEG)
Magnetoencephalography (MEG) measures the magnetic fields created by nerve cells in your brain. Often, it’s used with MRI scans to assess brain function. It also shows doctors where the seizures are starting.
Statistical parametric mapping (SPM)
Statistical parametric mapping (SPM) is a method for comparing your brain activity to those of people without epilepsy. It helps a doctor identify the region of your brain where the seizure is taking place. It’s mostly used for research purposes.
CURRY analysis
CURRY is a type of analysis technique. It combines data from EEG, MEG, and imaging tests to reveal where the seizures are occurring. Like SPM, it’s mostly used only for research, and isn’t used in practice.
Epilepsy diagnosis can take time. There’s also the potential risk of a misdiagnosis.
This is due to several reasons. For starters, seizures aren’t predictable. They usually happen outside of a doctor’s office, where medical professionals can’t observe symptoms as they happen.
Seizures can also have a wide variety of manifestations, from tingling to episodes of confusion. Sometimes, people aren’t aware they’re having seizures until someone else witnesses them.
There also isn’t a single medical feature that points to epilepsy. There are many characteristics and test results needed to confirm the condition.
Finally, EEG results can be misleading. There are many possible causes — including non-epileptic causes — behind abnormal EEG results.
After you receive an epilepsy diagnosis, the next step is to work on managing your seizures.
The goal of treatment is to reduce the frequency or severity of your seizures. Possible treatment options include:
You’ll also develop an epilepsy management plan with your healthcare team. The purpose of this plan is to control seizures and stay safe during daily activities.
Be sure to attend your regular checkups and follow your doctor’s recommendations. This is the best way to ensure your epilepsy is controlled.
Epilepsy is diagnosed by a neurologist. To start, they’ll perform a neurological exam to assess how well your nervous system is working. This includes questions about your symptoms, as well as your medical history.
A neurologist will also use blood tests, imaging scans, and EEGs to determine if you have epilepsy. If you receive a diagnosis, they’ll use different techniques to identify the types of seizures that you’re having.
Diagnosing epilepsy can be difficult. Until you receive a diagnosis, don’t hesitate to ask your doctors questions. If you experience new symptoms, tell your doctor.