Gelastic and Dacrystic Seizures
What are gelastic and dacrystic seizures?
Gelastic and dacrystic seizures are focal (or partial) seizures that start in an area at the base of the brain called the hypothalamus.
- Gelastic seizures is the term used to describe focal or partial seizures with bouts of uncontrolled laughing or giggling. They are often called laughing seizures. The person may look like they are smiling or smirking.
- Dacrystic seizures are focal or partial seizures when a person makes a crying sound. They may also look like they are grimacing.
- The emotions (laughing or crying) are often forced and the person can’t stop them from happening.
- Most people don’t feel happy or a sense of well-being during a gelastic seizure. The opposite may happen - they may feel scared or a loss of control. Some people may feel anxious that they will laugh at a socially inappropriate time.
- Usually a person is aware of what’s going on around them during these seizures.
What part of the brain do these seizures come from?
These focal or partial seizures come from the area of the brain called the hypothalamus. This is found at the base of the brain.
The gelastic or dacrystic seizures are usually seen in people with a lesion or area on the hypothalamus called a hamartoma. The term hypothalamic hamartoma or HH is used to describe this. This lesion or spot congenital (meaning it’s been present since birth) is not a type of cancer.
Seizures associated with HH usually start as focal seizures. Other seizure types may be seen as the person gets older. Gelastic and dacrystic seizures may spread to affect both sides of the brain, resulting in absence, atonic, tonic (also called drop attacks), and tonic-clonic seizures.
Who is at risk?
Gelastic and dacrystic seizures may not be recognized as seizures for years because of the way they look. People don’t expect that someone may laugh or cry during a seizure. Often the seizures go unrecognized until some other seizure type appears.
- These seizures begin in infancy in 1 out of 3 children. The average age when gelastic seizures start is around 10 months.
- Gelastic seizures often happen as a child is falling asleep, but they can occur at any time.
- Infants and children will be awakened from sleep by a gelastic seizure, then settle down and go right back to sleep.
What’s it like to have gelastic or dacrystic seizures?
Gelastic seizures are often short, lasting 10 to 20 seconds or less. They may look different with each child, yet there are some common features, such as:
- They often start with an aura. The person may look startled or even have a look of panic or fear.
- There can also be an unpleasant feeling in the stomach (like butterflies), a tickling in the chest or headache. Automatic behaviors, such as lip smacking or swallowing may be seen.
- The person may stare. Their eyes may seem vacant, dilate, and move up and to one side.
- There often is a slight smile that seems a bit forced and laughter or grunting that seems unusual or not appropriate at that time. In infants, there may be grunting and unusual squirming as well.
- Some children look for comfort from a parent or favorite toy for no apparent reason. Others may run to a place where they feel safe.
- Parents report that their child’s gelastic seizures appear triggered by loud noises or fearful responses to sudden actions.
- These seizures can occur many times a day. In some cases, as many as 100 a day have been seen.
How are gelastic and dacrystic seizures diagnosed?
Diagnosing these seizures can be hard since symptoms are usually missed or not considered seizures at first. Often, once parents hear a description of a gelastic seizure, they realize they had been happening for a while.
- Often the diagnosis is not made until a different type or more visible seizure happens. Three out of 4 people with HH and epilepsy will develop other types of seizures over time, including different types of generalized seizures.
- Diagnosis can be difficult too because EEG tests (electroencephalogram) are often normal or show minor changes or abnormal findings in children with only gelastic seizures. This is because the brain tissue where the seizures come from (the hamartoma) is deep in the brain. EEG changes are hard to pick up from this area, especially during a routine EEG when a person is not having a seizure.
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