The brain contains billions of nerve cells, or neurons, that communicate with one another by sending and receiving electrical signals. A seizure occurs when large groups of neurons fire at the same time and produce abnormal electrical activity — an “electrical storm” — that interrupts normal brain function. This sudden, temporary interruption in brain activity causes changes in behavior, sensation, movements, or awareness.

Brain damage is an injury to brain tissue that affects a person’s physical, emotional, or behavioral health. Brain damage may be caused by a head injury, an illness, or a condition. Typically, an isolated seizure doesn’t lead to lasting brain damage, but sometimes it has a negative effect on brain function. However, a person with uncontrolled epilepsy or rare, severe types of epilepsy may be at greater risk of brain damage.

What Causes Brain Damage?

Brain damage occurs when neurons and their connections are destroyed. It’s thought that some isolated seizures may negatively impact the brain, though many different types of seizures (including simple febrile seizures) aren’t linked to lasting brain injuries.

The risk for brain damage in epilepsy depends on factors including your age, how frequently you have seizures, what causes them, and how you respond to treatment.

Researchers in neurology believe that whether epileptic seizures can cause long-term brain damage depends on several factors, including:

• The type of seizures a person has
• The number of seizures they experience
• The frequency of seizures
• The duration of each seizure
• The cause of the seizures
• The response of a person’s epilepsy to treatments
• The age at which seizures occur

Isolated vs. Repeated Seizures

A seizure is a single event that a person experiences just once or rarely. Often called “isolated seizures,” they can be triggered by situations including:

• Low blood sodium
• Heavy drinking or withdrawal after alcohol abuse
• High fever
• Infection
• Brain tumor
• Specific medications

The type of seizure and how long it lasts affect its potential for brain damage. Seizures lasting longer than five minutes are medical emergencies.

Isolated seizures may not require specific treatment other than managing the underlying medical problem. However, seizures without a clear cause should be treated with an individualized plan and safety counseling. Isolated seizures do not always require anti-seizure medication, but in certain cases, starting treatment can reduce the risk of another seizure in the short term.

Repeated or recurring seizures are defined as having seizures more than once. You might not know the cause. When a person has two or more seizures at least 24 hours apart without another known cause, they are considered to have epilepsy.

How Long Can a Seizure Last Before Causing Brain Damage?

The longer a seizure lasts, the greater the potential for harm. While there isn’t a specific duration that guarantees brain damage, seizures lasting more than five minutes, as well as recurrent seizures without time to recover in between, require urgent medical attention. The type of seizure also plays a role in the risk.

For example, generalized convulsive seizures lasting more than five minutes are considered a medical emergency. Other types of seizures are less likely to cause serious brain injury unless they last for more than 30 to 60 minutes.

4 Seizure Types That May Cause Brain Damage

Some seizures listed below are known to cause negative long-term effects on brain function. Here, we discuss four kinds of seizures that put people at an increased risk for brain damage.

1. Refractory Epilepsy

Epilepsy can be challenging to treat, and not everyone responds well to anti-seizure medications. Some individuals develop drug resistance and continue to experience seizures despite taking medication — this condition is known as refractory, uncontrolled, intractable, or drug‑resistant epilepsy. In the U.S., about 30 percent to 40 percent of people with epilepsy have drug-resistant epilepsy.

People with refractory seizures are at a higher risk of brain damage compared to those with controlled epilepsy. People with uncontrolled or frequent generalized tonic-clonic seizures (more than three per year) are at a much higher risk of experiencing sudden unexplained death from epilepsy (SUDEP). Seizure control is the most effective way to reduce this risk.

Uncontrolled epilepsy can also result from misdiagnosis, improperly prescribed or used medications, or lifestyle factors such as a poor diet, high stress, and lack of sleep. If uncontrolled epilepsy doesn’t improve, it can cause brain damage and negatively affect a person’s quality of life.

2. Status Epilepticus

Another group at greater risk of brain damage from seizures includes those who experience episodes of status epilepticus.

A typical seizure lasts from 30 seconds to two minutes. However, in some cases, seizures occur back-to-back without giving the person time to fully recover, leaving them unconscious. When a seizure lasts longer than five minutes, or when recurrent seizures happen without recovery in between, it’s called status epilepticus. During status epilepticus, neurons can be destroyed, leading to permanent brain injury.

Although status epilepticus is rare, it can occur with any type of epilepsy or seizure. The condition is a medical emergency that may lead to permanent brain damage or death. One study found that people who survive status epilepticus may have significant changes in their behavior, learning, and memory. The researchers reported that this result seemed to especially affect children whose brains were still developing.

3. Temporal Lobe Epilepsy

People who experience temporal lobe seizures are at a higher risk of brain damage. Temporal lobe epilepsy often involves seizures that can be more challenging to treat compared to other types.

Studies have shown that prolonged focal impaired awareness seizures (seizures in one part of the brain causing confusion or reduced awareness) in temporal lobe epilepsy — especially when they progress to tonic-clonic seizures — can lead to declines in cognitive functions such as thinking, reasoning, and memory, as well as brain damage. (“Tonic-clonic” refers to the seizures’ two phases.)

Treatments can’t replace or heal lost brain cells. However, there are steps you can take to improve brain function and reduce further harm.

When medication is ineffective in temporal lobe epilepsy and seizures are severe, doctors may recommend surgery. For carefully selected people, epilepsy surgery can greatly reduce seizures and improve quality of life. However, surgery often involves removing the part of the brain where seizures originate. This can affect function depending on which part of the brain is removed.

4. Seizures in Children

Some types of seizures are more likely to cause brain damage in children than they are in adults, which may be related to the presence of specific epilepsy syndromes.

The brain undergoes significant growth and development from birth through adulthood, with the most critical period occurring during the first eight years. Infants and children with certain types of epilepsy may be at a higher risk of developmental challenges in cognitive, motor (muscular movement), and psychiatric (mental, emotional, and behavioral) functions. They’re also at greater risk of status epilepticus. That’s why, if your infant or child is experiencing seizures, it’s critical to seek medical care right away.

Severe seizures in a developing brain can cause changes in various brain structures and lead to neuron loss, resulting in brain abnormalities. Based on animal studies, researchers believe these changes can sometimes become irreversible, causing permanent brain damage. Keep in mind that these results are from animal studies, and it’s possible that children may recover. Additionally, infants who experience seizures during their first few months of life (known as infantile epileptic spasms syndrome) are at a higher risk of lifelong seizure activity, developmental problems, and even related death.

Consequences of Brain Damage

The effects of uncontrolled epilepsy, prolonged seizures, and recurrent seizures go beyond the injuries or accidents that may occur during the seizure. One risk factor involves damage to neurons, which can lead to brain damage. Examples of brain damage include:

• Impairment of cognitive processes such as memory and language
• Difficulties with school and learning
• Psychiatric symptoms such as depression or anxiety
• Difficulty with balance and coordination
• Repeated severe seizures
• SUDEP, which can happen with poorly controlled seizures or in status epilepticus

Additionally, a person’s disease progression may begin with focal seizures — affecting just one part of the brain — and later develop to generalized seizures (previously called grand mal) that affect multiple parts or the entire brain. This progression can complicate diagnosis and influence the long-term effects on brain function.

While these potential brain symptoms may seem alarming, it’s important to understand that each person’s experience with epilepsy is unique, and outcomes vary widely. Some people may have multiple seizures with few long-term effects, while others may develop serious brain damage.

Treatment Options for Brain Damage

Treatments can’t replace or heal lost neurons. The good news is that treatments such as neurorehabilitation, epilepsy medications, and diet patterns like the ketogenic diet can improve brain function and reduce further harm for many.

Additionally, researchers in healthcare are studying new ways to regenerate brain cells in clinical trials. These alternative therapies are experimental but may hold promise for people with epilepsy.

If you’re living with epilepsy, the most important step in avoiding brain damage is to address the underlying cause of the seizure (if known) and control seizures. This involves:

• Following a proper treatment plan consistently
• Adopting a healthy lifestyle to minimize the risk of worsening symptoms and triggering seizures
• Avoiding injuries that could lead to disability or brain damage

Preventing uncontrolled seizures should be the top priority to reduce the risk of permanent brain damage.

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