Doctor looking at a hologram of the brain above a tablet.

Diagnosing seizures: How to tell you’ve had one and types of tests

Updated 30/11/2021

After experiencing an unexpected seizure, getting a professional medical diagnosis should be one of the first things you do. Even if it’s over quickly or the symptoms don’t seem very extreme, having a seizure is usually a sign that something needs to be addressed and that professional medical help is probably necessary. As soon as you notice a seizure happening to you or someone you know, be sure to seek help as soon as possible.

How to tell you’ve had a seizure

Before anything else, recognizing you’ve had a seizure is the first step in diagnosing. This isn’t always as easy as it seems, as there are several varieties of seizures, some of which can be difficult to detect. You may be unconscious when the seizures happen, or they may even happen so quickly that it’s easy to miss. Seizure symptoms also vary and can occasionally seem like something else entirely.

Symptoms of seizures include:

  • Loss of consciousness or awareness

  • Involuntary movement of any kind. This can range from rubbing one’s forehead to running in circles. You may experience sudden jerking of certain muscles, causing certain parts of your body to move rapidly

  • Muscle stiffness, usually in the back, arms, and legs. May also cause you to lose balance and fall

  • Loss of muscle control, essentially making it impossible to control your muscles at all and also likely to cause falling

The following can be symptoms of seizures but only occur for some people:

  • Unexplained changes in emotion. This can include things such as sudden crying, shouting, or laughter

  • Unexplained sensations such as dizziness, pain, itchiness, and other sensations with no clear cause. This also extends to things like unusual sounds, smells, tastes, and sights

Doctor looking at a hologram of the brain on a tablet
[Image description: Doctor using tablet to display brain hologram. In the background, there are faded scans of the brain.]

Getting a professional diagnosis

Diagnosing seizures is not a simple process because causes are so varied. Seizures come in many different forms and sizes. Not all are caused by epilepsy as there are many different causes. That’s why you should understand what was happening to you before, during, and after the event has taken place. Any information you have can help your doctor narrow down the possible causes and determine which tests they should give you.

Initially, your primary doctor will ask you to recount information about the seizure. If you were unconscious or weren’t aware, it may be helpful to have someone there with you who witnessed the event. You can also prepare for this by keeping a log of your seizure activity using the Seer app if you experience multiple seizures. At this stage, any information about what may have caused your condition, what happened to you while it occurred, and your state afterwards will be most helpful.

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Tests for diagnosing seizures

Depending on what your doctor has been able to discover, there are many diagnostic tests they may choose to perform. Reaching a definitive answer can be difficult, but through a combination of tests, your doctor should be able to determine the most likely cause of your seizure and recommend further steps.

If this is your first seizure, your doctor may want to do some scans to look at the structures in your brain. A common form of imaging is MRI. Your doctor may also want to assess how the naturally occurring activity in your brain is functioning. To do this, an EEG is performed.

  • Magnetic Resonance Imaging (MRI) – This is a detailed way of looking for abnormalities in the brain such as lesions or tumors. A combination of powerful magnets and radio waves are used to map a complex representation of your brain.

  • Electroencephalogram (EEG) – Using electrodes attached to your head, your doctors can measure the electrical activity in your brain. This helps to look for patterns to determine if and when another seizure might occur, and it can also help them rule out other possibilities.

Medical reports
[Image description: Graphs and statistics overlaying a background of a stethoscope, medical data and a person typing on a laptop.]

Some additional diagnostic tests include:

  • Computer axial Tomography (CT) – This is a digital scan of your brain which can be used to look for abnormalities. It’s most useful for determining whether seizures are the result of tumors or cysts.

  • Positron Emission Tomography (PET) – Using a low dose of radioactive material inserted into a vein, doctors can check for abnormal brain activity that could determine the cause of seizures.

  • Single-Photon Emission Computerized Tomography (SPECT) – Like PET scans, a low dose of radioactive material is used to create a 3D map of the blood flow activity in your brain.

  • Lumbar Puncture – This test may be performed if your doctor suspects an infection may have caused your seizure. A sample of cerebrospinal fluid is removed.

  • Blood Tests – Signs in your blood such as infections, electrolytes, sugar levels, and genetic conditions may also help doctors determine the most likely cause of your seizures.