Triggers for partial-onset seizures may include sleep deprivation, stress, alcohol, or flashing lights.

Partial onset seizures begin in one area of the brain. Another term for partial seizures is focal seizures. Triggers are situations, states, or substances that can lead to seizures in people with epilepsy or another medical condition that causes seizures.

Triggers may vary for each person and depend on the underlying cause of the seizures. For example, some people with epilepsy have photosensitivity, in which case flashing lights can trigger seizures.

Generally, triggers can lead to atypical electrical activity in a specific brain area, causing someone to experience a seizure.

This article examines possible triggers for partial seizures, prevention, and outlook.

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According to the Epilepsy Foundation, around 3% of people with epilepsy may have flashing lights as a seizure trigger. The term for this is photosensitive epilepsy, which is more common in children and adolescents.

Certain levels of flashing, flickering lights, or contrasting light patterns may trigger a seizure. They can come from the following sources:

  • computer or television screens
  • video games
  • strobe lighting
  • sunlight reflecting off water or flickering through trees or slats of a blind
  • special lighting effects at events or concerts

Sleep patterns can greatly affect seizures. The sleep-wake cycle has links to changes in hormonal and electrical activity in the brain, and sleep deprivation may trigger seizures.

Practicing appropriate sleep hygiene and getting enough quality sleep each night may reduce the frequency, intensity, and length of seizures.

Learn more about sleep hygiene.

Having very low blood sugar levels, particularly in those who have diabetes and take excess insulin, may trigger seizures for some people. However, no evidence suggests mild drops in blood sugar will trigger seizures.

Hyperglycemic hyperosmolar state (HHS) is a serious complication of type 2 diabetes. People with HHS may have high blood sugar levels, dehydration, and acidosis. The latter refers to increased levels of acid in the body.

HHS can cause the following:

  • partial seizures
  • uncontrolled twitching
  • weakness on one side of the body

People will need immediate medical treatment for HHS.

According to the Epilepsy Foundation, dehydration may increase the number of seizures some people experience.

The body requires a certain amount of water to function properly. Even mild dehydration may negatively affect short-term memory, attention span, and motor skills.

People can aim to drink 8 cups of water daily to stay hydrated. Children need around 6–8 cups for optimal hydration.

An electrolyte imbalance may cause partial seizures. Electrolytes are substances, such as sodium, potassium, and calcium, that are essential for the body to function properly.

If electrolyte levels are too high or low, it can cause an imbalance that can be life threatening. Electrolyte imbalances which may cause seizures include:

  • hyponatremia, which is when sodium levels are too low
  • hypernatremia, which is when sodium levels are too high
  • hypomagnesemia, which is when magnesium levels are too low

Alcohol is a common seizure trigger for various reasons, as it can:

  • make antiseizure medication less effective
  • disrupt typical sleep, which may trigger seizures
  • lead to hangovers that dehydrate the brain and increase the risk of seizures

Still, the effect alcohol has on seizures depends largely on the individual.

In some people, recreational drugs may trigger seizures or increase seizure frequency. Drugs may also increase the risk of mental or physical issues, further increasing seizure risk.

According to a 2021 review, stress is one of the most common seizure triggers in people with epilepsy.

The release of the hormone cortisol due to stress may promote seizures. Chronic stress may reduce neurosteroids, which are steroids that the body naturally produces, and increase the risk of seizures.

Certain medications may trigger seizures. Over-the-counter medications containing diphenhydramine may trigger seizures in some people with epilepsy.

Also, certain cold medicines containing pseudoephedrine as an ingredient may reduce the seizure threshold. This refers to the resistance people have to seizures. Therefore, these medicines could make seizures more likely.

Avoiding common or personal triggers for partial seizures may help reduce their occurrence. Additionally, treating their underlying cause, such as an electrolyte imbalance, may help prevent future seizures.

Treatment for partial seizures with no known cause or those due to brain structure abnormalities may include antiseizure medications.

Alongside avoiding triggers where possible, getting enough sleep may help in partial seizure management. In some cases, following a ketogenic diet may also be beneficial. This diet is low in carbohydrates and protein and very high in fat.

Some common triggers for partial-onset seizures include lack of sleep, stress, and alcohol. Triggers may vary for each person and depend on the underlying cause of the seizures. For example, some people with epilepsy have photosensitivity, in which case flashing lights can trigger seizures.

Avoiding triggers where possible and taking antiseizure medication may help people control or prevent partial seizures.