Epilepsy is a complex neurological condition with well-established ties to sleep health.
Its 2-way relationship with the sleep-wake cycle makes it difficult to diagnose, especially for those who only have epileptic seizures at night (nocturnal seizures).
What is epilepsy and why does it share such common ground with sleep disorders?
Types of epilepsy
Epilepsy is a neurological condition characterized by patterns, or random activation, of seizure activity. Researchers still don't know what causes epilepsy, though certain factors may predict its onset, such as tumors, strokes, concussions, even a genetic predisposition.
Not all seizures are caused by epilepsy, but for those who do have epilepsy, their seizure activity leads to a number of challenges that are cognitive, medical, and social. People with epilepsy also suffer varying degrees of seizure activity and may not share common symptoms with others who also have epilepsy.
Thankfully epilepsy is not considered degenerative and is, for the most part, a manageable condition, with pharmaceutical and alternative treatments available.
What is a seizure?
A seizure is a sudden change in brain activity caused by increased electrical activity.
Also known as a convulsion, this increase in electrical activity can lead to something as simple as a silent period of staring or something more dramatic, including violent involuntary muscular contractions and/or unconsciousness.
Kinds of seizures
The type of seizures that people with epilepsy experience are defined by the convulsion's trigger and the point of origin for the seizure activity.
The most common triggers for epileptic seizure include emotional stress, sleep deprivation, and chronic fatigue.
According to the Epilepsy Foundation, "Seizures are very sensitive to sleep patterns. Some people have their first and only seizures after an 'all-nighter' at college or after not sleeping well for long periods."
The lobes most commonly impacted by seizures are the temporal lobe and the frontal lobe, though the occipital lobe is also affected, though less commonly.
A typical seizure lasts under a couple of minutes and is often preceded by an aura or other sensation several minutes prior to the actual event. This may be why seizures in sleep are so difficult to detect; there is no conscious warning to heed, since the epileptic is not conscious.
Epileptic seizures are either categorized as generalized or partial seizures.
Generalized seizures affect both sides of the brain and lead to post-seizure fatigue (called the postictal state).
Partial (or focal) seizures take place in one or more areas across one side of the brain.
The person having a partial seizure might experience a warning sensation prior to their events.
These seizure varieties further differentiate the condition.
Petit mal seizure (generalized): Symptoms include little or no movement, a brief loss of consciousness, and a blank stare.
Grand mal seizure (generalized): Symptoms include violent involuntary muscular contractions across the whole body, loss of consciousness, pauses in breathing, urinary incontinence, tongue or cheek biting, and confusion or weakness following the event.
Atonic seizure (generalized): Also called a "drop attack," this sudden loss of muscle tone resembles the cataplexy of narcolepsy.
Myoclonic seizures (generalized). Symptoms include quick, sudden jerking movements occurring in clusters across a muscle group. They can happen several times a day over the course of several days.
Simple partial seizure (partial or focal): Symptoms include muscle contractions or jerking movements only in limited locations across the body while fully conscious, with numbness or tingling, nausea, sweating, and dilated pupils.
Complex partial seizure (partial or focal): Symptoms include automatic behavior (physical movement without purpose), a loss of consciousness that can still include a blank stare, communicative unresponsiveness, the expression of inappropriate emotions, and strange smell or taste hallucinations.
There are even more differentiations to be made, but for the purposes of this article, these are the key types, and they can happen during the day or as sleep seizures.
Epilepsy and sleep: familiar bedfellows
The relationship between epilepsy and sleep is complex and has been the subject of study since the late 1800s after correlation between sleep and seizures was documented.
The process of sleep can activate seizure activity; the brain is, contrary to popular thinking, very active during sleep, when major electrical and hormonal activity takes place. It's this activity which can predispose an epileptic to nocturnal seizures. Research shows that this seizure activity follows a cycle, just as circadian rhythms are also cyclical.
Epileptic activity is also shaped by sleep stages and their transitions.
Most activity is linked to NREM stage sleep (stages 1, 2, and 3) while seizures can be partially prevented during REM sleep.
In addition, the sleep architecture of someone with epilepsy will be influenced by their disorder and can include:
increases in how long it takes to fall asleep
higher arousal events throughout the night
more wakefulness after sleep onset (WASO) (a measure of sleep quality)
less efficient sleep
reduced or broken REM sleep
As one can guess, these can all add up to chronic sleep deprivation for the person with epilepsy.
For some epileptics, seizures only happen while they sleep, while others experience them at other times of the day (or at all times in their sleep-wake cycles). Others may have all of their seizures during sleeping, or while falling asleep or waking up. And for many epileptics, inadequate sleep may be enough to aggravate seizure activity that has been triggered by other reasons.
When sleep disorders mimic epilepsy
In medical jargon, epilepsy and sleep disorders have what is called a bidirectional relationship: that is, epilepsy disturbs sleep, and sleep deprivation aggravates epilepsy. What's more, treatments for epilepsy can further disrupt healthy sleep.
In addition, separate sleep disorders can be more pervasive in those with epilepsy, or they can mimic symptoms of epilepsy, making it difficult to identify and diagnose either without sophisticated tests.
Insomnia, or epilepsy?
Certain kinds of epilepsy have a distinct association to sleep, such as Rolandic epilepsy, more commonly known as benign focal epilepsy of childhood. For people with this condition, seizures during sleep cause arousals that are easily confused with the symptoms of insomnia.
These patients may not realize their "insomnia" is actually the byproduct of untreated epilepsy, and they may suffer daytime sleepiness and cognitive problems for years without realizing their sleeplessness at night has a treatable cause.
Sleep apnea and epilepsy
According to research from the University of Michigan that was published by the National Sleep Foundation, sleep apnea is likely to occur in as many as a third of all epilepsy patients. These patients were also found to be more likely to have convulsive events at night when compared to those epilepsy patients who did not have sleep apnea.
The Epilepsy Foundation also references the connection: "In one series, obstructive sleep apnea was found in 71 percent of people with epilepsy who were referred for a sleep study."
Research is now focused on sleep apnea therapies to see if they can lessen the severity and frequency of epileptic events for those who have both conditions.
Other common sleep disorders or conditions which mimic epilepsy
Confusional arousals (“sleep drunkenness”)
Sleep-wake transition disorders (i.e. hypnic jerks, sleep talking, rhythmic movement disorder)
Bedwetting (sleep enuresis)
REM sleep behavior disorder
How do physicians uncover epilepsy when so many sleep disorders may potentially hide its diagnosis? Assessments used to identify epilepsy include:
Magnetic resonance imaging (MRI)
Computed tomography scan (also called a CT or CAT scan)
Lumbar puncture (spinal tap)
- Overnight sleep studies (NPSGs) to uncover seizure activity that is suspected to take place only during sleep
Chronic health problems common to both sleep disorders and epilepsy
People with epilepsy may have a higher risk for developing the following problems, which also happen to be common to many sleep disorders:
Depression and mood disorders
Given the close resemblance that disordered sleep shares with epilepsy, and other health risk factors they both share, it makes sense to identify (through sleep or neurological tests) the root cause (or causes) of a person's sleep problems, especially when they appear to be of neurological origin and they have a history of seizure-like symptoms or behaviors.
This is best determined through a visit (or, likely, multiple visits) with a medical practitioner and, potentially, a sleep specialist, who can order the appropriate diagnostic assessments to determine a proper diagnosis.
Johns Hopkins Medicine
National Sleep Foundation
University of Michigan