The cells in your brain communicate with your muscles, nerves, and other parts of your brain via electrical signals. Sometimes, these signals go haywire, sending too many or too few messages. When this happens, the result is a seizure.

You can have a seizure associated with any form of epilepsy, even while you sleep. But with certain types of epilepsy, seizures only occur during sleep.

Epilepsy is the most common cause of seizures. Doctors make an epilepsy diagnosis when you have two or more unprovoked seizures at least 24 hours apart, not caused by another medical condition.

About 3.4 million people in the United States have epilepsy. You can get it at any time. According to the Epilepsy Foundation in 2014, new cases are most often diagnosed in children under the age of 10 and adults over the age of 55.

As with epilepsy, there are many different kinds of seizures. They fall roughly into two categories: generalized seizures and focal, or partial, seizures.

Generalized seizures

A generalized seizure happens when abnormal electrical activity occurs in both cerebral hemispheres. Included in this category are:

  • Tonic-clonic seizures. Formerly known as grand mal, these seizures include a stiffening of the body, jerking motions, and usually loss of consciousness.
  • Absence seizures. Formerly known as petit mal, these seizures are characterized by brief periods of staring, blinking eyes, and small movements in the hands and arms.

Partial seizures

Partial seizures, also called focal or localized seizures, are limited to one hemisphere of your brain. When they occur, you may remain conscious but may not know the seizure is happening. Partial seizures can affect behavior, consciousness, and responsiveness. They also can include involuntary movements.

Many types of epilepsy associated with nighttime seizures start in childhood. For example, in children with benign rolandic epilepsy, about 70 to 80 percent of seizures occur while sleeping.

Types of epilepsy associated with nighttime seizures include:

According to 2014 research, almost two-thirds of seizures occur between 8 p.m. and 8 a.m. It’s estimated that, in people with seizures:

  • about 20 percent experience seizures during sleep
  • about 41 percent experience seizures during the day
  • about 39 percent experience seizures during the day and night

Some other studies estimate that about 12 percent of epilepsies cause nighttime seizures almost exclusively. Both focal and generalized seizures can occur during sleep, but focal seizures are more common.

People with epilepsy who experience nighttime seizures have more than twice the risk of sudden, unexpected death than people who only experience seizures in the day.

Sleep deprivation is very common among people with epilepsy. Lack of sleep can potentially lead to more frequent seizures, since sleep deprivation is one of the main risk factors.

Most common seizure times and sleep stages

It’s believed that sleep seizures are triggered by changes in the electrical activity in your brain during certain stages of sleeping and waking. Nighttime seizures occur most often in the early morning around 5 a.m. to 6 a.m. and occur least often shortly after falling asleep. Some types of epilepsy, such as infantile spasms, tend to cause seizures shortly after waking.

Sleep is divided into stages called rapid eye movement (REM) sleep and non-REM sleep. Non-REM sleep is divided into three phases called N1, N2, and N3.

Compared with REM sleep, focal seizures are estimated to occur:

  • 87 times more often in N1
  • 68 times more often in N2
  • 51 times more often in N3

Compared with REM sleep, generalized seizures are estimated to occur:

  • 3.1 times more often in N1
  • 3.13 times more often in N2
  • 6.59 times more often in N3

It can be hard to recognize nocturnal seizures, especially in children, but symptoms can include:

  • crying out
  • unusual noises
  • convulsions
  • bedwetting
  • muscle twitches or jerks
  • tongue biting
  • falling out of bed
  • trouble waking after seizure
  • suddenly waking
  • strange movements or postures while sleeping

About 3.4 million adults in the United States have epilepsy. Seizures and epilepsy are most common in infants and children under age 15. Children who have epilepsy often stop having seizures by the time they reach adulthood.

Parents of new infants sometimes confuse a condition called benign neonatal sleep myoclonus with epilepsy. Infants experiencing myoclonus have involuntary jerking that often looks like a seizure.

In cases of myoclonus, an electroencephalogram (EEG) won’t likely show changes in the brain that are consistent with epilepsy. Additionally, myoclonus is rarely serious. For example, hiccups and jerking in sleep are forms of myoclonus.

It can be tricky to diagnose nocturnal seizures because of when they occur. Sleep seizures can also be confused with parasomnia, an umbrella term for a group of sleep disorders. These disorders include:

To determine which form of epilepsy you may have, a doctor will evaluate a number of factors, including:

  • the type of seizures you have
  • the age when you began having seizures
  • family history of epilepsy
  • other medical conditions you may have

To diagnose epilepsy, a doctor may use:

  • images of electrical activity in your brain recorded by an EEG
  • the structure of your brain as shown in a CT scan or MRI
  • a record of your seizure activity

If you suspect that your infant or child is having nighttime seizures, consult with their doctor. You can monitor your child by:

  • using a baby monitor so you can hear and see if a seizure occurs
  • watching for signs in the morning, such as unusual sleepiness, headache, and signs of drooling, vomiting, or bedwetting
  • using a seizure monitor, which has features like motion, noise, and moisture sensors

Speak with a doctor if you believe you or your child is experiencing seizures while sleeping. The doctor can order tests that will confirm if you’re experiencing seizures.

Medication is the first-line treatment for epilepsy. A doctor will help find a treatment that works best for you or your child. With proper diagnosis and treatment, most cases of epilepsy can be managed with medications.