The Human Brain
The brain is made up of millions of nerve cells called neurons. These cells generate electrical impulses and messages to produce thoughts, feelings, sensations, movement and control body functions.
Regions of the brain
The brain is divided into two halves, left and right, called hemispheres. The right hemisphere controls the left side of the body and left hemisphere controls the right. Each hemisphere has four lobes – frontal, parietal, temporal and occipital.
This is the largest structure of the brain and contains the frontal, parietal, occipital and temporal lobes. It is the centre of intellect, memory, language and consciousness, receiving and interpreting sensory information and controlling movement.
Are considered our emotional control centre and home to our personality. They are also involved in motor function (movement), problem solving, spontaneity, memory, language, initiation, judgement, impulse control, and social and sexual behaviour.
Are involved with touch, temperature and pain perception (sensation), awareness of the body and where it is in space.
Play a large role in language, speech, hearing, memory, personality and behaviour.
Are primarily responsible for vision
Is the stem-like part of the base of the brain that is connected to the spinal cord. It controls the flow of messages between the brain and the rest of the body, and also controls basic body functions such as breathing, swallowing, heart rate, blood pressure, consciousness, and whether one is awake or sleepy.
The cerebellum is responsible for co-ordination, and maintaining of posture, muscle tone, and balance.
If you want to know more about the brain and its functions, go to:
What is a Seizure?
Seizures and epilepsy are not the same.
A seizure happens when the normal alternating pattern of these electrical impulses are disrupted, causing them to rapidly fire all at once.
Depending on where the seizure in the brain, this can cause changes in:
- sensation and feeling
- awareness and consciousness
- emotions and behaviour
Seizures vary greatly and can be very brief or last up to two or three minutes. Most seizures are over in less than two minutes. Some seizures are severe and some very subtle.
Not all seizures are diagnosed as epilepsy.
A seizure is an event – a disruption of the normal electrochemical activity of the brain – and epilepsy is a disease of the brain characterised by the tendency to have recurrent seizures.
Under certain circumstances, anyone can have a seizure.
What is epilepsy?
Epilepsy is a common disease of the brain where there is a tendency to have recurrent seizures. It is a neurological disorder—not a form of mental illness—and seizures are caused by a temporary disruption of the electrical activity in the brain.
Approximately 3% to 3.5% of Australians will experience epilepsy at some point in their lives and over 250,000 Australians currently live with epilepsy.
Epilepsy can start at any age although it is more likely to be diagnosed in childhood or senior years.
There are many different types of epilepsies and people’s experiences differ greatly. Some types of epilepsy are age-limited and the person eventually stops having seizures. For others, epilepsy is a life-long condition.
Approximately two thirds of people with epilepsy become seizure free with medication.
The cause of epilepsy can be identified in about half of people with epilepsy, but the remaining half never find out why they have epilepsy.
Some known causes of epilepsy include:
- head injury such as in a car accident, trauma or serious fall
- stroke or brain haemorrhage
- lack of oxygen to the brain for a prolonged period (such as in birth trauma, cardiac arrest, drowning, drug overdose)
- brain infections (for example meningitis, encephalitis or brain abscess)
- brain abnormalities at birth
- brain tumours
- genetic factors
- degenerative conditions affecting the brain (such as dementia).
Seizure Types and Classification
Seizure classification is a way of naming the many different types of epileptic seizures and putting them into groups.
In 2017, the International League Against Epilepsy revised its classification of seizures to make diagnosing and classifying seizures more accurate and simpler. Some of the words you may have heard to describe seizures, such as ‘tonic-clonic’ are still used while others, such as ‘partial’ and ‘grand mal’ are no longer used.
Doctors look at the following three things when classifying a seizure:
- Where in the brain the seizure starts (e.g. the onset)
- If the person is aware or not during the seizure
- Whether the seizure involves movement.
Seizures can be divided into three major groups:
Most people will only have one or two seizure types. Sometimes a person with more complex or severe epilepsy may experience a number of different seizure types.
1. Focal Onset Seizures
Focal onset (formerly known as partial seizures) means the seizure starts in just one small region of the brain. It may spread to other areas of the brain.
These seizures can often be subtle or unusual and may go unnoticed or be mistaken for anything from being intoxicated to daydreaming. About 60% of people with epilepsy have focal onset seizures – which are also simply known as focal seizures.
Focal onset seizures can be further divided into two groups relating to a person’s awareness during a seizure:
- Focal aware: the person is fully aware of what’s happening around them but may not be able to talk or respond (formerly known as simple partial seizures). They are usually brief, and are often called a warning or ‘aura’ (that a more significant seizure may develop) but are actually part of the seizure.
- Focal impaired awareness: awareness is affected (formerly known as a complex partial seizure) and the person may appear confused, vague or disorientated.
A focal seizure may progress to a bilateral tonic-clonic seizure meaning that it starts in one area of the brain and then spreads to both sides causing muscle stiffening and jerking.
2. Generalised Onset Seizures
Generalised onset means the seizure affects both hemispheres (sides) of the brain from the onset. Because of this, a person may lose consciousness at the start of the seizure. Generalised onset seizures almost always affect awareness in some way, so the terms ‘aware’ or ‘impaired awareness’ aren’t used. However, they can be classified further by movement:
- Generalised motor seizure: may involve stiffening (tonic) and jerking (clonic), known as tonic-clonic (previously known as grand mal) or other movements
- Generalised non-motor seizure: These seizures involve brief changes in awareness, staring, and some may have automatic or repeated movements like lip-smacking.
Types of Generalised Onset Seizures
There are many types of seizures in this classification. They include:
- Absence – a sudden lapse in awareness and responsiveness that look like brief staring spells or daydreaming
- Tonic-Clonic – the body stiffens (the tonic phase) and then the limbs begin to jerk rhythmically (the clonic phase)
- Myoclonic – sudden single jerks of a muscle or a group of muscles that may last no more than a second or two
- Tonic – Can occur when a person is asleep or awake and involves a brief stiffening of the body arms or legs. The person will suddenly fall if standing or sitting.
- Atonic – brief seizures that cause a sudden loss muscle tone and the person often falls to the ground or will have a sudden head nod if sitting.
- Clonic – although uncommon they cause jerking in various parts of the body
3. Unknown Onset Seizures
Unknown onset means the seizure cannot be diagnosed as either focal or generalised onset. Sometimes this classification is temporary and as more information becomes available over time or through further testing, the type of seizure may be changed to a generalised or focal onset seizure.
Rarely, doctors might be sure that someone has had an epileptic seizure, but can’t decide what type of seizure it is. This could be because they don’t have enough information about the seizure, or the symptoms of the seizure are unusual.
Most people will only have one or two seizure type(s), which may vary in severity. A person with severe or complex epilepsy or significant damage to the brain may experience a number of different seizure types.
Watch here for the most common types of seizures explained
What the Seizures Look Like
Focal seizures are classified by whether awareness is retained or impaired (altered). If awareness is unknown, then they are simply classified as a focal seizure.
Focal seizures – retains awareness
Sometimes a focal seizure does not alter consciousness and the person is aware of what is going on around them during the seizure. These seizures are known as focal aware seizures.
People often refer to these seizures as their “aura” but they are actually a seizure which may or may not lead on to a more significant seizure. For instance, the seizure may spread to become a focal impaired awareness seizure or evolve into a bilateral tonic clonic seizure.
Examples of focal aware seizures include:
- Focal motor seizures – movements, such as jerking, posturing or stiffening of arm/s or leg/s, twitching of face
- Focal sensory seizures –sensations, such as numbness, tingling or burning feeling in a part of the body
- Focal autonomic seizures – involuntary body changes, such as blushing, looking pale or grey, increased heart rate, butterflies in the stomach, nausea, and perspiring
- Focal cognitive seizures – include impaired language or thinking, or features such as déjà vu, hallucinations (visual, smell, taste or hearing), illusions or perceptual distortions
- Focal emotional seizures – characterised by feeling emotions such as joy, sadness, anxiety, fear or panic.
Focal seizures – impaired awareness
In some types of focal seizures, the person has a change in awareness, consciousness, and behaviour. These are called focal impaired awareness seizures. They can also be called focal seizures.
These focal seizures vary greatly, depending on where they start and spread within the brain and are frequently not recognised as seizures by onlookers. Many of these seizures begin with:
- A vacant stare, loss of expression or a vague, confused appearance
- Consciousness or awareness is altered and the person may or may not respond
- If they do respond, it is usually inappropriate to the situation
- Sometimes people have unusual and repetitive behaviour such as chewing, fidgeting, walking around or mumbling
- The seizure can range from 30 seconds to 3 minutes
- After the seizure, the person is often confused for a short time, and may not remember anything that happened before or during the event.
Tonic clonic seizures
A tonic clonic seizure is a seizure that has a tonic (muscle stiffening) and a clonic (muscle jerking) phase, typically in this order, but variations such as clonic-tonic-clonic can also be seen. Tonic clonic seizures are the most recognised seizure type and can be frightening to witness. There are slight variations, but a typical tonic clonic seizure will look like:
- A sudden loss of consciousness, sometimes with vocalisation or calling out
- The eyes, head and body may turn in one direction
- The body becomes stiff (tonic), followed by jerking of the muscles (clonic)
- If standing, the person will fall
- Breathing may be shallow or briefly stopped which may cause the lips and face to look greyish/blue
- The person will not respond when spoken to
- Excess saliva may come of the person’s mouth, and there may also be blood if they have bitten their tongue or the inside of their cheek
- There may be loss of bladder or bowel control so the person may wet or soil themselves
- The seizure usually lasts 2 minutes or less
- Immediately after the seizure breathing can be quite laboured and sound like heaving snoring (usually less than a minute)
- After the seizure there is usually a period of confusion, headache, soreness and sleep.
A myoclonic seizure is a seizure where a single jerk or series of single jerks (very brief muscle jerks) occur. They frequently affect the upper body, neck shoulders and arms. A person having a myoclonic seizure usually has sudden jerks on both sides of the body at the same time. They vary in severity but can cause someone to spill or drop what they are holding, or fall off a chair. If severe enough, a myoclonic seizure can also cause a fall.
The seizures are often mistaken for clumsiness before diagnosis.
Note: Even people without epilepsy can experience myoclonus or sudden jerks just as you are falling asleep. These are normal and not seizures.
A tonic seizure involves increased muscle tone of the body usually very brief, lasting a few seconds. If the person is standing they will suddenly fall stiffly to the ground. This is often termed a “drop attack” (astatic seizure).
Tonic seizures often occur during sleep and in clusters of varying intensity of tonic stiffening. The person is unaware during these events. At the beginning of tonic seizures with more intense stiffening, people may make an exhalation or loud sigh sound. With more severe and prolonged tonic seizures the person may look like they have a tremor or shaking.
Tonic seizures often occur in people with intellectual impairment or more complex epilepsies.
An atonic seizure is a type of seizure that involves the sudden loss of muscle tone. If standing, this can cause a “drop attack” where the person suddenly slumps to the ground. If sitting, a simple head nod (as if the person is trying to fight off sleep) may be seen. These seizures are very brief, less than 2 seconds and may involve the head, body or limbs.
Atonic seizures often occur in people with intellectual impairment or more complex epilepsies.
*Clonic seizures (less common)
A clonic seizure is a seizure involving bilateral rhythmic jerking and may occur alone or in combination with tonic (increased muscle tone) activity typically lasting a few seconds up to a minute. The jerking in a clonic seizure is more sustained and rhythmic than seen in a myoclonic seizure.
The most common absence seizure is the typical absence seizure. There are other less common types of absence seizures that are briefly discussed here.
A typical absence seizure starts and ends abruptly, is very brief with altered awareness during the seizure. Absence seizures usually begin in childhood (but can occur in adolescents and adults) and are easily missed, or misinterpreted as daydreaming or inattentiveness.
Typically, it will look like:
- the seizure starts suddenly with the person stopping their activity
- you will see staring, loss of facial expression and unresponsiveness
- sometimes eye blinking or upward eye movements are seen
- the seizure can last from two to 20 seconds and ends abruptly
- the person usually recovers immediately and resumes their previous activity, with no memory of what happened during the seizure
These seizures can happen numerous times a day causing learning to be disrupted. They generally respond well to medication.
The below group are less common absence seizure types:
*Atypical absence seizures
The seizure does not start and end as suddenly as a typical absence, it can be more gradual. They are often seen with other features such as loss of muscle tone of the head, trunk or limbs (often seen as a gradual slump) and subtle jerking. These seizures often occur in people with intellectual impairment and complex epilepsies.
The loss of awareness may be minor with the person continuing an activity, but more slowly or with mistakes.
Rhythmic myoclonic jerks of the shoulders and arms and lifting of the arms during the seizure can be seen. The myoclonic jerks are usually seen in both arms, but may be one-sided or not symmetrical. Puckering (jerking) of the lips, twitching of the corners of the mouth, or jaw jerking can also be seen. Sometimes rhythmic jerks of the head and legs may occur. Seizures last 10-60 seconds and typically occur daily.
The level of awareness varies from complete loss of awareness to retained awareness.
*Absence with eyelid myoclonia
These are absence seizures accompanied by brief, often rhythmic, fast myoclonic jerks of the eyelids at the same time with an upward movement of the eyeballs and of the head. This can look like fluttering of the eyelids and simultaneous rolling back of the eyes. These seizures are typically very brief and occur many times a day.
Mostly awareness is retained.
This is a relatively new classification.
There are seizures that cannot be clearly diagnosed as focal or generalised, and may even be considered both. The “Unknown Onset” classification is used when a seizure is unable to be classified due to either:
- not enough information or
- an unusual nature of the seizure, or
- the inability to classify the seizure as either focal or generalised onset.
Unknown onset seizures are not truly separate types of seizures, but temporary labels for seizure types for which the onset is unknown. As more information becomes available over time or through further testing, the seizure type may be changed to a generalised or focal onset seizure.
For instance a person reports having a tonic clonic seizure, but the start of the seizure was not seen. Therefore it is uncertain if it was a focal or generalised onset.
Epileptic spasms are classified in unknown onset
Epileptic spasms (which include infantile spasms) are seen in infants and appear like:
- A sudden bending or lunging forward (flexion) of the upper body followed by stiffening
- Often the arms are flung out as the knees are pulled up and the body bends forward
- Less often, the head can be thrown back (extension) as the body and legs stiffen in a straight-out position
- Movements can be more subtle and limited to grimacing or head nodding
- These spasms are longer than a myoclonic jerk, but shorter than a tonic seizure.
Each seizure lasts only a second or two but they usually occur in clusters, several in a row.
What is a Syndrome?
There are many different types of epilepsy classifications. Many people are now given a specific diagnosis or name for their epilepsy, rather than just told that ‘you have epilepsy’. Some types of epilepsy are further classified as syndromes and are defined based on a unique combination of symptoms.
An epilepsy syndrome is a type of epilepsy that depends upon:
- family history
- what age the seizures start
- seizure type(s)
- cause, and other linked diseases/conditions
- how the syndrome progresses over time
- presence or absence of brain abnormalities
- EEG findings
- brain scan findings (such as CT, MRI, PET)
- seizures response to medication.
A diagnosis of a particular epilepsy syndrome is useful in deciding the possible treatment options, what course the condition may take, and the possible genetic risk of passing it on to offspring.
Some types of epilepsy syndromes are:
- Childhood absence epilepsy (CAE)
- Childhood epilepsy with centrotemporal spikes (Rolandic epilepsy)
- Dravet syndrome
- West syndrome (Infantile spasms)
- Doose syndrome (Myoclonic Astatic Epilepsy (MAE))
- Rasmussen’s syndrome
- Lennox-Gastaut syndrome (LGS)
- Landau-Kleffner syndrome (LKS)
- Sturge-Weber syndrome (SWS)
- Juvenile myoclonic epilepsy (JME).
and many more.
What is photosensitive epilepsy?
In some people, seizures can be triggered by flashing or flickering lights, or by certain geometric shapes or patterns. This is called photosensitive epilepsy. Some people with epilepsy only have photosensitive seizures, whilst others may have other seizure types as well as photosensitive seizures.
This is a type of reflex epilepsy is seen in up to 5% of people with epilepsy, and because the seizures are usually triggered by some sort of visual stimulation, they can be reduced with simple avoidance strategies. Medication is usually used to help gain seizure control.
Although prognosis is generally very good, photosensitive seizures may persist.
How do I know if I have photosensitive epilepsy?
It is important to have a clear diagnosis, and keep good records or a seizure diary to help differentiate the seizures and their triggers. Photosensitive epilepsy can be diagnosed by having a routine EEG with strobe (flickering) light or pattern stimulation. A routine EEG should include this.
Today’s lifestyle can involve spending many hours using (visual) technology. While a seizure may occur in these conditions, it may also be a spontaneous or chance event – so don’t conclude your seizures are photosensitive seizures just because you had one or two when using technology.
How is it treated?
In most cases the photosensitive seizures can be well controlled by antiepileptic medication and avoiding known triggers.
What are the triggers?
Our modern environment is a rich source of potentially seizure-triggering visual stimuli. Typical sources can include:
- strobe lighting
- television, electronic or video games, or the images on the screen
- shimmering sunlight reflected off snow or water, or sunlight filtering through trees whilst in a moving vehicle
- venetian blinds
- striped walls or clothing
Less common stimuli are:
- moving escalators
- rotating helicopter blades
- faulty fluorescent lights
- welding lights
- mobile phone flashes
New potentially provocative sources turn up now and then unexpectedly.
What are other factors involved?
Whether or not a photosensitive seizure happens is also influenced by:
- whether the eyes are open, closed or closing at the time of the stimulation
- the speed or flicker of the flashing (light)
- the contrast and brightness of the stimuli – in general, with brighter stimuli and strong contrasts in colour, the more likelihood of inducing seizures
- how long the stimulation goes for – a seizure is more likely to occur with longer exposure
- the colour of the flicker (if any) – red flicker is more provocative and colour oscillating from red to blue
- how large and close the screen is – the larger and closer someone is, the more “field of view” it takes up and is more likely to trigger a seizure
Managing photosensitive epilepsy
Types of stimuli that may trigger a seizure
Almost all people with photosensitive epilepsy are sensitive to flickering lights. Many natural light sources can provoke epileptic seizures as well. With the increasing use of technology, there is more exposure to provoking factors (e.g. screen time, visual images and strobe lights) than ever before. Avoiding sources of triggers is the best advice.
The following precautions only apply to those people who are diagnosed with photosensitive epilepsy.
Television: There are many different types of screen technology, and modern television screens are much less likely to trigger seizures. An older cathode ray tube (CRT) TV created its picture with flicker and although not recommended, if you get very close to the screen you can see the flicker.
Liquid crystal display (LCD) and plasma screen televisions do not use the scanning lines and therefore are less likely to trigger seizures than the older CRT televisions. Plasma screens tend to be brighter and have higher contrast than LCD televisions; this increased contrast may increase the risk of seizure activation.
For people with photosensitive epilepsy, the current advice is to opt for an LCD TV over a plasma TV.
It is important to keep a good distance from any screen because seizures may be provoked by images on the screen such as, flashing sequences or rapid changes from light to dark or to contrasting colours, such as from red to blue, rather than from the screen itself. So, the further away you sit from the screen, the less likely a seizure will occur.
It has not been proven that 3D movies are any more likely to trigger a seizure than 2D movies if someone has photosensitive epilepsy.
- Sit at least 2.5 metres from a television screen in a well-lit room
- Sit at an angle rather than directly in front of the screen
- Don’t watch the screen in the dark
- Use a remote control or cover one eye to lessen the effect if you have to change channels manually
- Do not watch the screen when fast forwarding, rewinding or adjusting the vertical hold
- In the cinema, try to sit well back from the screen and near a light source, such as in an aisle seat where there is a guiding light
- Look away from any content that makes you feel uncomfortable
- A smaller screen set at low brightness and contrast is preferable.
In daily life, other factors such as sleep deprivation and drug or alcohol use may also play a role in provoking photosensitive seizures.
Video games: Apart from the screen display, the content and images of video-games are play a role in photosensitive seizures. Other factors that may play a role, particularly if the game is being played for a long time, include emotional excitement or tension, fatigue, eyestrain and difficulties sleeping, which can contribute to seizures.
Also, people tend to sit closer to a video game screen than when watching a TV program.
- Sit as far away from the screen as possible
- Play the game in a well-lit room and reduce the brightness of the display
- Avoid continuous exposure to the same pattern and don’t play when overtired
- Check games for epilepsy or seizure warnings
- If you do find that a game(s) makes you feel like you are going to have a seizure, then it is best to stop playing and keep exposure to the game in short bursts (have a break every 10-15 minutes) or avoid that particular game altogether.
It is good to take regular breaks from any electronic games and refresh.
Computer monitors: It is uncommon for a computer screen to trigger a seizure. Only in exceptional cases would it be necessary to restrict computer work. If you are sensitive to screen flicker on older monitors, a screen filter may help. You could always try an anti-glare filter to reduce screen glare. High quality monitors, liquid crystal or LCD screens with a flicker (refresh) rate of at least 60Hz may not pose a problem. Once again, it is more likely to be the images on the screen that may cause a seizure.
It is uncommon for seizures to be triggered by hand-held screens.
3D movies: There is much hype and concern about the effect of 3D movies being a seizure trigger, but this is not the case. In people with photosensitive epilepsy, the risks of a seizure being triggered by 3D movies is no greater than conventional 2D programmes. For people with non-photosensitive epilepsy the risk of 3D movies triggering a seizure is negligible.
Lights: The frequency of a flashing or flickering light most likely to trigger seizures will vary from person to person. Generally it is between 8-30 flashes per second, but this can vary. Many people seem to be sensitive around 15-20 flashes per second. Again, it is also dependent on the brightness and intensity of the light, and how long the person is exposed to it.
Ordinary lighting in a room is preferable to fluorescent, but faulty fluorescent lights are rarely the trigger of a seizure
Fans: Ceiling fans in a lit room can create a flicker effect. A pedestal fan is best if you feel the ceiling fan may trigger a seizure.
Geometric patterns: Some people are sensitive to geometric patterns which have strong contrasts of light and dark such as stripes or checks. Some of these patterns can create an optical illusion. Some buildings and public places may have large areas like this, such as carpet. The average person will just feel some visual distortion, but if you feel strange in this environment, it is important to leave or at least cover one eye.
These patterns may also be on a television or computer screen, or something in the natural environment, such as sunlight through trees, or through Venetian blinds. Such contrasting patterns are more likely to be a trigger if they are moving, changing direction or flashing, rather than if they are still.
Camera flashes: These rarely trigger seizures unless fired in rapid succession.
Red flickering light and strobe/disco lights: These can trigger seizures, particularly if the room is darkened and there are other triggers such as stress, excitement, tiredness, sleep deprivation and alcohol. For those who are photosensitive, the risk will greatly depend on the speed of the flashing light.
- It is sensible to avoid strobe lighting like those at nightclub’s and music festivals if you have photosensitive epilepsy, but this is a common social activity for young people, so it may be a hard one to resist. Some people these events even if they are photosensitive, and find they can tolerate it. Responsible clubs and DJs may display warnings if these lights are used and retail employers may turn off flashing lights in their store if requested.
Sunlight: This can trigger seizures in a number of ways such as: the shimmering of light off water or through leaves of trees, and light flickering through posts or railings when moving quickly, such as travelling past in a vehicle. Some people may even be affected by looking outside through a screen door.
- Cover one eye with the hand to lessen the effect of the flicker as binocular (looking through both eyes) vision is needed to trigger a seizure.
- Polaroid sunglasses or Zeiss Clarlet F133 Z1 Blue lenses may also help reduce the risk.
Knowing what sources may trigger your photosensitive seizures, and reducing your exposure to them plays a significant role in reducing or stopping this type of seizure. Many people still need medication, but try to:
- Avoid events with strobe lighting if you can
- Avoid video games with high contrast flashing and have frequent breaks if playing video games
- Cover or patch one eye if you cannot avoid certain sources of stimulus (eg travelling in a vehicle when sunlight is flickering through the trees)
- Wear glasses that reduce the amount of light as much as possible, such as polarised sunglasses
- Blue lenses, (type Zeiss Clarlet F133 Z1), have proven effective for many people
- Use smaller TVs and computer screens. Ask about specific computer screens when purchasing a computer
- Reduce the contrast of TV and computer screens
- Use a remote control
- Keep a good distance to any screen (ideally at least three times its width)
- When using any screen, keep the room well lit.
These are general suggestions, and depending on your sensitivity, not all approaches may be necessary or effective.
For more information go to:
Factsheet: Photosensitive Epilepsy
Nocturnal Seizures – Seizures during Sleep
Sleep and seizures – the facts
- Sleep deprivation is one of the most commonly reported seizure triggers by people with epilepsy
- Nocturnal seizures, even if only brief can disrupt sleep and increase daytime drowsiness
- Drowsiness can increase the risk of daytime seizures for people who would normally only have seizures during sleep
- Nocturnal seizures may be misdiagnosed as a sleep disorder and vice versa
- Nocturnal seizures are a risk factor for Sudden Unexpected Death in Epilepsy (SUDEP)
- Some antiepileptic drugs can contribute to sleeping difficulties or daytime drowsiness
- Sleep apnoea is about twice as common in people with poorly controlled epilepsy than in the general population
- People with epilepsy and a sleep disorder have a poorer quality of life compared to those with no sleep disorder. Treatment of the sleep disorder improves seizure control and quality of life
- Lastly, sleep disorders can exacerbate seizures and epilepsy can exacerbate certain sleep disorders
Why do so many seizures happen during sleep?
Seizures during sleep can occur with any type of epilepsy. Some people have seizures occurring only during sleep whilst others have both daytime and night-time seizures. People who have only night-time seizures in their sleep are defined as having nocturnal epilepsy.
The International League Against Epilepsy (ILAE) defines nocturnal seizures as ‘seizures occurring exclusively or predominantly (more than 90%) from sleep.’
It is estimated around 12 percent of people with epilepsy have nocturnal seizures.
Why do nocturnal seizures occur?
Epileptic seizures are often strongly influenced by the sleep-wake cycle.
When we go off to sleep, we have a change of state – from awake to asleep. But during sleep, there are many changes of state, which are called sleep stages. It is thought that a change of state has an effect on the brains ‘epileptic activity’ in people with epilepsy. Some seizures occur predominantly at a certain stages of sleep.
It’s believed that nocturnal seizures are triggered by changes in the electrical activity in your brain when moving between the different stages of sleep, and between sleep and awakening stage. As an example, in wakefulness, our brain waves remain fairly constant, but during sleep there are many changes. We go to bed and shift from
- wakefulness to drowsiness to
- light sleep to deep sleep to
- Rapid Eye Movement (REM) sleep
- and this whole cycle occurs 3-4 times per night.
There are dramatic changes on EEG during these sleep stage changes.
Stages of Sleep
Sleep is divided into 5 stages: Non-REM Stages 1, 2, 3, and 4 and REM sleep.
Seizures don’t seem to happen during REM sleep, but may occur at any other time during the sleep cycle, often in light sleep – that is, stages 1 and 2 of sleep. Nocturnal seizures can also occur when waking or stirring during the night.
This generally means there are more common times at which nocturnal seizures happen:
- Within the first or second hour after going off to sleep (early nocturnal seizures)
- One to two hours before the usual time of wakening (early morning seizures)
- Within the first hour or so after awakening (early morning seizures).
Seizures that occur during sleep may also happen during a daytime nap – they are not limited to night time.
Table 1 Stages of Sleep
|Stage 1 – Sleep Onset Non-REM sleep||Stage 2 Non-REM sleep||Stage 3 Non-REM sleep||Stage 4 Non-REM sleep||Stage 5 REM sleep|
|Drowsiness/ very light sleep, easily awoken||Light sleep||Deep sleep starts||Deep sleep||“Active” sleep. When you dream|
|This is when you start falling asleep, and is usually brief.||Your brain activity heart rate and breathing start to slow down. You begin to reach a state of total relaxation in preparation for the deeper sleep to come.||This is also known as slow wave sleep. Your brain waves further slow but there may still be short bursts of faster of brain activity.
If you were to be suddenly awoken during this stage, you would be groggy and confused, and find it difficult to focus at first.
|This is where you experience your deepest sleep of the night. Your brain is mostly slow wave activity, and it’s difficult to wake someone up when they are in this stage.||Your blood flow, breathing, and brain activity increases, but your muscles go into a paralysis-like state. The brain activity is similar to when you are awake.|
Diagnosing nocturnal seizures
It can be difficult to diagnose nocturnal seizures because they happen during sleep, and the person may not be aware of them happening. Also, nocturnal seizures, particularly focal seizures, can be confused with some sleep disorders.
As with most other forms of epilepsy, a good history of the seizures, or even better, an eyewitness account is very important for diagnosis. The doctor may also suggest a video sleep EEG, often done during the day after being sleep deprived.
If left undiagnosed, the person may suffer from a lot of daytime sleepiness.
This can impact concentration, attention and learning as well as behaviour and emotions resulting in reduced quality of life.
Are there specific types of epilepsy where people have nocturnal seizures?
Nocturnal seizures can happen to anyone with epilepsy, but they are often associated with certain types of epilepsy, including:
- Juvenile Myoclonic Epilepsy (JME)
- Epilepsy with Generalised Tonic Clonic Alone
- Childhood Epilepsy with Centro-Temporal Spikes (also called Benign Rolandic Epilepsy of Childhood)
- Electrical Status Epilepticus of Sleep (ESES or CSWS)
- Landau-Kleffner Syndrome (LKS)
- Frontal Onset Seizures (such as Nocturnal Frontal Lobe Epilepsy)
Nocturnal seizures can be any type of seizures. Sometimes they are too subtle to detect.
Can they change to daytime seizures?
If a person has seizures only during sleep for several years, the chances of the seizures happening during wakefulness is small. However this does not mean daytime seizures won’t occur. For example, in situations of extreme stress, sleep deprivation or illness, medication changes or withdrawal, the risk of a seizure is increased, day or night. Daytime seizures may also occur if someone with nocturnal epilepsy decides to take a nap, or even becomes excessively drowsy during the day.
With good seizure and lifestyle management however, the risks of a daytime seizure can be greatly reduced.
How are they managed?
- It is important to aim for the best seizure control possible because nocturnal seizures can disrupt sleep, sometimes quite a lot. This can then become a cycle of sleep deprivation, which is a known trigger for seizures, and consequently more seizures
- Treatment of nocturnal seizures is generally the same as daytime seizures, although sometimes the specialist may recommend a higher evening dose of antiepileptic medication
- Medical management of seizures is based on the type of seizures rather than when they occur
Sudden Unexpected Death in Epilepsy (SUDEP) is when a person with epilepsy dies suddenly and prematurely and no reason for death is found. SUDEP deaths are often unwitnessed with many of the deaths occurring overnight during sleep. There may be obvious signs a seizure has happened, though this isn’t always the case.
Although the risk of SUDEP is very low, the risk increases for people with tonic-clonic seizures, especially if they happen at night or when asleep. Click here to take action against this risk
We also have a SUDEP and Safety Checklist which your GP or Epilepsy Nurse can discuss with you.
Practice good sleep habits
Some tips for getting a good night’s sleep include:
- Keep the same bedtime and rising times as much as possible
- Work with your internal body clock, so don’t ignore tiredness, go to bed when your body tells you so
- Make sure your bedroom is a restful and calm place to be. Keep it dark at night and open the blinds when you wake up
- Shift work is not ideal as it affects sleep times and quality of sleep
- Don’t use screens – smart phones or tablets – for at least an hour before bedtime
- Some people who have difficulties sleeping, or have interrupted sleep, use sedatives which may ultimately aggravate the problem. Try to improve your sleep regime with more natural techniques
- Try not to resort to large amounts of coffee or other forms of stimulants to overcome tiredness. Avoid any caffeinated products or stimulating substances after lunch as this can also affect sleep quality and affect seizures for some people
- Regular exercise can improve a restful sleep. Don’t exercise within four hours of bedtime though
- Keep evening activities calm or use relaxation techniques to establish a more efficient sleep pattern. If there are things you are worried about, try not to think about them just before bedtime
- A regular routine is vital with some people
- If you have tried and failed to improve your sleep, there are many sleep specialists that can help.
For a person with nocturnal seizures, it is suggested:
- Choose a low bed, avoid sleeping on a top bunk
- Keep furniture away from the bedside to prevent injury during a fall
- Consider using a safety mats on the floor next to the bed if the person tends to fall out of bed during seizures. Such mats are similar to those used in gyms
- Wall mounted lamps pose less safety risks than ordinary table lamps or study lamps, which can be easily knocked over
- Smoking in bed is unwise for anyone and particularly so for a person with nocturnal seizures
- There are a number of devices for night-time seizure monitoring available for use in the home. They are designed to recognise that a seizure has occurred or that breathing has been disrupted, triggering an alarm so that help can be provided. An alarm or device cannot guarantee the safety of a person experiencing nocturnal seizures, however, some families have found monitors to be a useful part of a risk reduction plan and provide peace of mind
- Some people advocate for the use of special anti-suffocation pillows to allow better airflow around the face. Whilst they are quite porous and allow airflow, the use of these pillows has not been proven to prevent death from suffocation nor guarantee the safety of a person having nocturnal seizures. The use of a special pillow is a personal choice
- If there is someone available to help you if you have a seizure, check they know how to put you into the recovery position (onto your side) and what to do in case of emergency. See our First Aid page for advice
- Finally, people who experience seizures exclusively during sleep may be allowed to drive.
For more information go to:
Sleep and epilepsy – Neurologist Dr Dan McLaughlin speaks about epilepsy and sleep
Factsheet – Nocturnal Seizures