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What happens right before a seizure?

A seizure is a sudden, uncontrolled electrical disturbance in the brain. It can cause changes in your behavior, movements or feelings, and in levels of consciousness. If you have had a seizure before, you may feel or behave differently before another one occurs. Knowing the warning signs before a seizure happens can help you stay safe.

What are the phases of a seizure?

Seizures can be divided into three phases:

1. Prodrome: This is the period leading up to the seizure, when you may experience warning signs or a “pre-seizure” feeling. Not everyone has a prodrome phase before seizures.

2. Ictus: This is the actual seizure event, when abnormal electrical activity occurs in the brain.

3. Postictal: This is the recovery period after the seizure ends, which may involve feeling confused, sleepy or experiencing other effects.

The prodrome phase, before the seizure itself, is most relevant when looking for warning signs.

Do seizures always have warning signs?

For many people with epilepsy, their seizures happen without any warning. These unpredictable, sudden seizures are called unprovoked seizures.

However, some people do experience consistent warning signs and symptoms before a seizure happens. These are called prodromal symptoms, and they occur during the prodrome phase leading up to the seizure event.

Prodromal symptoms are not experienced by everyone. Even someone who sometimes has warning signs may not have them before every seizure. But being aware of possible early symptoms can be helpful.

What are some common warning signs before a seizure?

If you experience any unusual symptoms or sensations before your seizures, take note of them. Here are some of the most commonly reported prodromal symptoms:

– Strange sensations: Feeling odd smells that aren’t there (phantoosmia), abnormal tastes (dysgeusia), seeing flickering lights (visual hallucinations), tingling, numbness, and skin crawling or itching.

– Lightheadedness: Feeling faint, dizzy or like you may lose consciousness. The room may seem to be spinning.

– Mood changes: Feeling nervous, anxious, sad, irritable, restless or fearful for no apparent reason. Sudden mood swings.

– Cognitive changes: Having trouble thinking clearly, difficulty finding words, memory lapses, spaciness or absence seizures (brief loss of awareness).

– Fatigue: Feeling tired, sleepy, drained of energy. Yawning frequently.

– Head and body cues: Headache, nausea, stomach pain, rapid heartbeat, sweating, shortness of breath or flushing face.

– “Aura” sensations: An unusual sensation that precedes a seizure, which may manifest as a visual disturbance, strange smell, taste or feeling. The aura is actually a simple partial seizure that can progress to a larger seizure.

If you regularly experience any of these warning signs before your seizures, pay attention to how long the symptoms last. Taking note of your own prodromal patterns can help you anticipate your seizures and get to safety.

Are there warning signs for specific seizure types?

The prodromal symptoms may differ slightly based on the type of seizure. Here are some details on early warning signs for major seizure classifications:

Focal (partial) seizures: These seizures originate in one area of the brain. Warning signs may indicate the part of the brain where the seizure begins. For example, if it starts in the temporal lobe, you might have early signs like déja vu, a rising feeling in the stomach, or hallucinations of smell or taste.

Generalized seizures: These involve electrical disturbances in both sides of the brain. Early signs may be more related to changes in awareness or responsiveness. For instance, feeling “spacey,” having staring spells, and brief loss of awareness (absence seizures).

Tonic-clonic seizures: Also known as grand mal seizures, these involve stiffening and jerking movements of the entire body. Prodromal symptoms may include strange smells, tingling, dizziness, mood changes, nausea and other signs listed above.

Atonic seizures: These are brief seizures involving a loss of muscle tone, which may cause you to suddenly collapse or drop objects you’re holding. Warning signs can include headaches, feeling faint, and losing awareness.

Myoclonic seizures: These brief, shock-like jerks of a muscle or muscle group have warning signs similar to those for tonic-clonic and atonic seizures.

Keeping a record of your prodromal patterns and any correlation with seizure type can help identify possible early warning signs.

Why is it useful to identify early seizure signs?

Recognizing your own early seizure warning symptoms, if you have them, can provide many potential benefits:

To get to safety – If you feel a seizure coming on, you may have time to get out of an unsafe situation, lie down to prevent injury, or call for help.

Avoid triggers – Knowing triggers like lack of sleep or specific flashing lights that may precede your seizures can help you avoid those triggers when possible.

Alert others – You can let friends, family or co-workers know a seizure may be coming soon so they can assist or alert emergency contacts.

Track patterns – Keeping a record of any warning signs and related seizure events can help you and your doctor identify any associated patterns and early predictors.

Manage medication – Discussing prodromal symptoms with your doctor may lead to adjusting medication to better control seizures and warning signs.

Identifying your own pre-seizure signs and symptoms allows you to be proactive and minimize risk of injury during a seizure.

How can I track prodromal symptoms effectively?

Using a seizure tracking tool can help you log any unusual sensations, symptoms or behaviors that may precede your seizures. Here are some tips for tracking early warning signs:

– Note the time any prodromal symptoms start and how long they last.

– Rate the severity of symptoms (mild, moderate, severe).

– Describe any sensations, feelings or actions in detail.

– Track symptoms on a daily basis so you can identify patterns.

– Log the date and timing of any seizures that followed prodromal symptoms.

– Report your tracked symptoms and patterns to your doctor.

– Use a seizure diary, app or online tracker to record episodes, prodromal phases, and seizures electronically for easy reference.

Consistent tracking provides valuable data to detect possible early seizure predictors based on your own experiences. Share your tracking details with your doctor to improve seizure management.

What should I do when I notice warning signs?

If you experience possible pre-seizure symptoms:

– Move carefully to a safe place if you feel a seizure coming on, and lie down if possible.

– Alert someone nearby who can help keep you safe or call for assistance.

– Take any prescribed emergency medication that your doctor advised for seizure auras or oncoming seizures.

– Stay calm, track symptom details, and breathe steadily. Anxiety may trigger more symptoms.

– Avoid potential harm by not driving, operating machinery, swimming alone, showering, etc.

– Do not restrain the person or put anything in their mouth during a seizure.

– Carefully time the seizure event from beginning to end.

– After the seizure, provide reassurance and do not leave them alone until fully recovered.

Following seizure first aid guidance can help minimize risk and prevent injury if a seizure does occur after warning signs.

Are there medical tests to diagnose early signs?

Doctors may utilize tests to help identify potential early indicators of a seizure by analyzing your brain activity. Some tests used include:

EEG monitoring: An electroencephalogram (EEG) traces electrical patterns in the brain and can detect abnormal discharges that may not cause visible symptoms. Some abnormalities may flag increased seizure risk.

fMRI imaging: Functional MRI scans show brain activity in different regions. Increased activity may signify early seizure activity.

PET scans: An injection traces glucose metabolism in the brain. Changes may indicate areas at risk of seizure activity.

Pre-surgical monitoring: If epilepsy surgery is considered, prolonged monitoring identifies seizure onset zones in the brain.

Serum markers: Levels of compounds in the blood like prolactin may help identify recent seizure activity.

Doctors may also check for triggers like sleep deprivation, medication levels, and metabolic changes that reduce the seizure threshold.

Are there ways to predict seizures with technology?

Wearable devices and mobile apps are being researched to help predict seizures through tracking biometrics. Some examples include:

Smart watches: Track heart rate, perspiration, motion and sleep to flag early signs like fatigue and stress.

Headbands and caps: Sensors that monitor electrical activity in the brain may detect patterns predictive of increased seizure risk.

Apps with patient input: Users log symptoms, triggers, treatments and other data to find correlations with seizure occurrence.

Seizure alert dogs: Some dogs can detect subtle chemical changes and behaviors that precede their human companion’s seizures.

These innovations show promise to identify reliable biomarkers and patterns that foreshadow seizures for an individual. More research is underway to evaluate their prediction accuracy.

Are there risk factors that make seizure prediction more likely?

Certain individuals may have higher odds of being able to predict their seizures based on prodromal symptoms or monitoring:

Consistent auras: People who have a distinct pre-seizure feeling like a specific smell or taste have improved ability to recognize an oncoming seizure.

Seizure clusters: Someone who frequently has flurries of multiple seizures may identify early signs of an imminent cluster period.

Night seizures: Nocturnal seizures often strike at a consistent part of the sleep cycle, allowing prediction based on time of night.

Catamenial epilepsy: Seizures linked to the menstrual cycle due to hormone changes may be anticipated around menstruation.

Strong triggers: If seizures are consistently provoked by things like lack of sleep, drinking alcohol or stress, associated early cues are more likely.

Tracking patterns specific to your epilepsy type and seizure triggers can help identify possible predictive factors.

What are some limitations of predicting seizures?

While identifying individual early seizure warning signs shows promise, there are still challenges and constraints on reliably predicting seizures for many people:

Inconsistent prodromal symptoms: Warning signs differ across seizures and may be absent before some seizures.

Short time frame: The prodromal phase may only occur minutes to hours before the seizure itself.

Non-epileptic seizures: Psychological seizures without abnormal brain activity can lack predictive signs.

Unclear correlation: More research is needed to definitively link prodromal symptoms as direct precursors to seizures.

Subtle signs: Changes detected by technology as predictive may be imperceptible to the patient themselves.

Cost barriers: Medical tests and monitoring devices can be expensive and often are not covered by insurance.

Stress trigger: For some patients, proactively worrying about an impending seizure itself may trigger seizure activity.

While more work is being done, seizure prediction remains limited. Having an effective treatment plan with your doctor is critical, regardless of your ability to anticipate seizures.


Identifying your own prodromal signs and patterns that precede your seizures can provide valuable insight. Paying attention to subtle changes in feelings, sensations, mood and cognition might give you advance warning of an impending seizure. If you think you may have reliable early seizure predictors, diligently tracking your symptoms and potential correlations can help in discussions with your doctor to improve seizure management. However, limitations exist on definitively predicting seizures. Maintaining consistent treatment and self-care habits is vital for living well with epilepsy, regardless of seizure predictability. Increased understanding of pre-seizure brain activity continues to advance research towards more reliable seizure forecasting and risk assessment to minimize their impact when they do occur.