Nocturnal frontal lobe epilepsy (NFLE) causes seizures while a person is asleep. It is a rare genetic condition that passes from parents to children.

Nocturnal frontal lobe epilepsy (NFLE) is now called sleep-related hypermotor epilepsy (SHE).

Epilepsy is a chronic seizure disorder that causes excessive electrical signals to occur in the brain, causing seizures. Several types of epilepsy may occur depending on the types of seizures, when they occur, what causes them, and which parts of the brain they affect.

A note about NFLE

This article will use the term SHE to refer to NFLE, as clinicians have described this as a more accurate way to address the symptoms.

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SHE causes seizures while a person sleeps. Doctors first described the condition in 1981 based on the night-time movements of five people. They were unsure whether this was a movement disorder or a form of epilepsy. By using electroencephalography (EEG), the doctors identified epilepsy-like electrical activity in the brain.

Since then, the condition’s name has changed from NFLE to SHE as it describes several vital aspects of the condition:

  • sleep brings on seizures
  • seizures arise from parts of the brain outside the frontal lobe
  • people move during the seizures

SHE is rare, with reports of it occurring in just over 100 families worldwide. One large 2015 study in Italy suggested that 18 in every million people may have SHE. However, the exact global prevalence of the disorder is unclear.

Most SHE seizures occur during sleep, but some people with this type of epilepsy experience daytime seizures. The seizures generally occur in groups, and the individual seizures often last for several seconds but may continue for a few minutes. Most seizures last under 2 minutes.

Some mild seizures wake an individual up but do not cause involuntary movements. Others are more severe, causing repetitive, sudden motions that may involve:

  • throwing motions
  • swinging the arms around
  • cycling with the legs

People with SHE may leave the bed and walk around the room, which resembles sleepwalking but is not the same.

People may make vocal sounds during SHE seizures, including:

  • groans
  • gasps
  • moans
  • cries

Onlookers such as sleeping partners may confuse these for nightmares or panic attacks. These seizures may disturb sleep and lead to drowsiness during waking hours.

SHE is a type of epilepsy that causes an aura, or a series of sensations ahead of a seizure. These include:

  • tingling
  • shivering
  • fearfulness
  • dizziness
  • a sensation similar to being pushed or falling
  • occasionally, breathlessness or rapid breathing

Most people with SHE do not experience cognitive, developmental, or intellectual impairment between seizures. However, an increasing body of research suggests that SHE may lead to cognitive and behavioral problems.

Some people with this type of epilepsy have also had diagnoses of schizophrenia, behavioral issues, or intellectual disabilities, but the link between these additional impairments and SHE is unclear.

The seizures generally become less severe and happen less often over time.

Most people with SHE do not have a known cause for the condition. However, clinical findings have linked several different causes with SHE, including:

  • Focal cortical dysplasia (FCD): This is the most common cause in people who require surgery to treat SHE that does not respond to medication. FCD involves the abnormal organization of nerve cells on the brain’s outer layer.
  • Injury: Physical damage is another structural anomaly that can lead to SHE in some people.
  • Genetics: Mutations in specific genes, including CHRNA2, CHRNA4, and CHRNB2, can lead to SHE, as can KCNT1, DEPDC5, NPRL2, and others. These gene changes may affect how the brain releases and absorbs chemical messengers called neurotransmitters, potentially leading to altered brain activity in people with SHE.

SHE is autosomal dominant, which means a person only needs to inherit a single copy of the mutated gene to develop the condition. Most people with SHE have a single affected parent and other family members with SHE.

Males and females have an equal risk of developing SHE. However, 85 in 100 people with SHE have a diagnosis before 20 years of age, and the symptoms usually begin at around 9 years of age.

To diagnose SHE, healthcare professionals will carry out the following steps:

  • taking a full medical history and physical examination
  • carrying out an EEG, usually including a video EEG to capture the hypermotor events during sleep, although this may show normal results in many people with SHE
  • genetic testing to check for the mutated gene variants
  • completing an MRI to rule out FCD

SHE and many sleep disorders overlap, as the condition involves involuntary movements during sleep, such as sleepwalking, night terrors, and confusional arousal, also known as parasomnias. These can also occur alongside SHE, making diagnosis complex.

The diagnostic criteria for SHE include:

  • seizures lasting 2 minutes or less
  • seizures occurring mainly during sleep
  • hypermotor events, meaning excessive movement or unusual posturing during sleep

The healthcare professional will use the video EEG to confirm SHE and other measures to guide diagnosis.

Treatment for SHE usually involves medications. Anti-seizure medications can be effective at treating SHE for many people, including:

Other medications include but are not limited to the following:

Medications cannot stop seizures for around 3 in 10 people with SHE. Surgery may be necessary for some people with FCD whose SHE symptoms do not respond to medications.

People with treatment-resistant SHE should visit an epilepsy specialist or center and discuss treatment options.

Individuals who experience cluster seizures due to SHE may need emergency rescue therapy, which may include diazepam gel inserted rectally or other benzodiazepines under the tongue or in the nose.

Can nocturnal epilepsy be cured?

No cure is available for SHE, but medications and other treatments may help people control symptoms.

Is frontal lobe epilepsy progressive?

SHE does not get worse over time. However, for many people, seizures become milder and less frequent as they get older.

Epilepsy resources

Visit our dedicated hub for more research-backed information and in-depth resources on epilepsy and seizures.

Sleep-related hypermotor epilepsy (SHE), formerly known as nocturnal frontal lobe epilepsy (NFLE), is a rare form of epilepsy that mainly causes brief seizures and involuntary movements while people sleep.

Some people with SHE may experience cognitive and behavioral problems, but symptoms often get milder over time.

SHE can occur due to focal cortical dysplasia, injury, or genetic mutations. Diagnosing SHE can be complex, but a video EEG and genetic testing can help confirm an SHE diagnosis.

Treatment typically includes anti-seizure medications, but these do not always work. Emergency rescue therapy may help people relieve cluster seizures.