Imagine suddenly laughing when nothing is funny and being unable to stop. Maybe people around you think you’re joking or simply laughing at the wrong time rather than experiencing a neurological event. Gelastic seizures, sometimes called laughing seizures, are rare seizures that cause sudden, uncontrollable laughter. They can happen in both children and adults.

One MyEpilepsyTeam member shared what this can feel like: “My family nicknamed me ‘Happy’ because I laughed so much, and at the most awkward moments as a child. Nothing was funny.”

Here, we discuss what gelastic seizures can look like, why they happen, and what treatment may help.

🗳️ Do you or your child with epilepsy experience sudden bouts of uncontrollable laughter?

Yes, and I/they have been diagnosed with gelastic seizures

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What Are Gelastic Seizures?

Gelastic seizures are focal seizures, meaning they begin in one area of the brain. They’re most often linked to the hypothalamus, a deep, tiny coordinating structure at the center of the brain. Seizures can also arise from other parts of the brain, particularly the frontal and temporal lobes.

These seizures are usually brief, often lasting less than a minute — around 10 to 30 seconds — but they may happen several times a day.

Gelastic seizures cause episodes of laughter, while dacrystic seizures, a related type of seizure, cause sudden episodes of crying. Some people may experience both of these types.

“I had a laughing seizure while talking with my daughter. I drifted away for a few minutes, and she said I just started laughing. There were no jokes or triggers.”

— A MyEpilepsyTeam member

Causes of Gelastic Seizures, Including Hypothalamic Hamartoma

A hypothalamic hamartoma (HH) is a congenital, noncancerous malformation that forms in the hypothalamus before birth and acts as an electrical short circuit. It’s the most common cause of gelastic seizures. When an HH is the cause, seizures often begin in infancy or early childhood, although they can start later.

“For years, we didn’t know why my son was laughing like that. At 5, an MRI showed he had an HH. It was a scary discovery, but reading about it, everything made sense,” shared one MyEpilepsyTeam member.

However, not everyone with gelastic seizures has an HH.

The laughter may offer clues. One small study found that seizures arising outside the hypothalamus involve laughter that sounded more mechanical or lacked a feeling of amusement. However, the way a seizure looks or sounds isn’t enough to establish its cause, and detailed brain imaging may be required.

Gelastic Seizures in Babies and Infants

In babies and young children, gelastic seizures may be mistaken for ordinary smiles or laughter. Because the episodes are often brief, parents may easily mistake the event for a happy developmental milestone and not realize that their child is experiencing a seizure.

Some children with HH develop other types of seizures over time, including tonic-clonic seizures. Learning, behavior, or mood disorders may also occur. An HH can also cause central precocious puberty, or puberty that begins unusually early.

If your child has repeated episodes of unexplained laughter or you notice new seizure types, developmental changes, or signs of early puberty, consulting a pediatrician or pediatric neurologist early is vital.

How Are Gelastic Seizures Diagnosed?

Gelastic seizures can be difficult to recognize because sudden laughing or giggling may not look like a seizure. Parents sometimes realize only later that their child’s unusual laughing spells were early seizures.

To make a diagnosis, your neurologist will consider what happens during the episodes, your medical history, the results of a thorough neurological examination, and test results. Testing may include an electroencephalogram (EEG) and brain MRI to uncover the root cause.

Electroencephalogram

An EEG records electrical activity in the brain, but it may be normal during a gelastic seizure, especially when an HH is involved. Video EEG, which records the episode and brain activity at the same time, may provide additional information.

Brain MRI

A high-resolution 3T brain MRI using an epilepsy-specific protocol can help identify a small HH that may be difficult to see on routine imaging.

Doctors may order additional tests such as hormone assays for premature or precocious puberty associated with hypothalamic involvement.

Treatment Options for Gelastic Seizures

Treatment for gelastic seizures depends on their cause, how often they occur, and how well they respond to medications. Treatment options include anti-seizure medications and, in some cases, surgery.

Anti-Seizure Medications

Gelastic seizures can arise from the frontal or temporal lobes, and some people with gelastic seizures not associated with an HH respond well to anti-seizure medications. The medication prescribed depends on the type of seizures a person has.

Gelastic seizures caused by an HH, however, are often difficult to control with medication. Anti-seizure medications may still help control other seizure types that occur with HH. There’s no single anti-seizure medication that works best for HH-related epilepsy. Options may include brivaracetam (Briviact), carbamazepine (Tegretol), levetiracetam (Keppra), oxcarbazepine (Trileptal), among others.

Because HH-related epilepsy is often drug-resistant, health experts recommend beginning a surgery evaluation early.

Surgery

When an HH is causing the seizures, surgical treatment can target the HH itself. Minimally invasive options include MRI-guided laser interstitial thermal therapy (LITT) and radiofrequency treatment, which use heat to destroy the tissue causing the seizures. Another option, stereotactic radiosurgery, uses focused radiation. One type of stereotactic radiosurgery used is called Gamma Knife radiosurgery.

The best approach depends on factors such as the size and location of the HH and the person’s individual needs.

One MyEpilepsyTeam member shared, “I’ve had three brain surgeries for HH, and since my last surgery, I’ve been seizure-free for more than six years.”

“I’ve had three brain surgeries for HH, and since my last surgery, I’ve been seizure-free for more than six years.”

— A MyEpilepsyTeam member

Talk With Your Neurologist

If you think you or your child may be having gelastic seizures, talk with a neurologist. Because these seizures can be easy to overlook, getting the right diagnosis is an important first step toward finding treatment that can help.

Before your appointment, write down any questions or concerns you have. Your neurologist can help you understand what’s happening and recommend what to do next.