This page is a work in progress. It is clear DEE-SWAS information that stays true to research, but is easier to read, understand and explain.

The rare epilepsy that rewires a child’s brain during sleep

  • Why are there so many names?

    You might feel confused about why there are so many names for this.

    • When my child was first diagnosed, we were told it was CSWS or ESES.

    • A year or two later, when I read more, I started seeing DEE-SWAS.

    • Now I understand that my child has EE-SWAS.

    In online groups, people use different names. This can depend on what their doctor says, or when their child was diagnosed.

    All of these names describe very similar conditions.

    So what’s going on?

    Over time, doctors have named different parts of the same thing:

    • ESES / CSWS describe the brain waves seen on an EEG in sleep

    • Landau-Kleffner syndrome is a type that mostly affects speech

    • Newer names like DEE-SWAS show this is not just epilepsy - it also affects how our children learn, grow and change over time.

    Why hasn’t this been made simpler for us?

    • Doctors working in this field trained at different times when different names were used - they’ve held on to the name they were taught

    • As a result, studies they do also use different terms

    • Some doctors prefer more specific labels. e.g. A doctor might use Landau–Kleffner syndrome if speech is the main issue.

    How it affects patients and families

    This can make it hard families to find clear health information, feel confident the information we find relates to our child’s diagnosis, and make sense of what it means for their day-to-day life.

    It can also make it harder to explain to the important people in your child’s life.

    For example, your child might be diagnosed with CSWS, but the most helpful online health information to share with their teacher is written under DEE-SWAS.

    Educators are busy and the simpler we can make it to support our child, the more confident we feel that our child can get the support they need at school.

  • 1920s to 1930s
    Brain waves are discovered

    Early EEG research made it possible to recognise this condition.

    1970s
    Sleep shown to be important

    This is when doctors discovered that unusual brain activity during sleep can cause learning, communication and behaviour changes.

    1970s to 2000s
    A condition is recognised

    Doctors begin to name this as a syndrome linked to:

    • abnormal brain activity in sleep

    • loss or slowing of skills

    • changes in behaviour

    ESES and CSWS become the names used. The focus goes from seizures alone to how a child is learning and developing. No clear cause recognised.

    Subclinical "Electrical Status Epilepticus" Induced by Sleep in Children

    2000s to 2010s
    A spectrum is recognised

    Doctors see CSWS/ESES is not one condition, but a range, with different ways it shows up and how the child changes over time.

    This includes overlap with:

    2013
    First gene link found

    In 2013, a gene called GRIN2A was discovered to be a cause in some children with conditions like CSWS and Landau–Kleffner syndrome. This was one of the first clear genetic links.

    GRIN2A mutations cause epilepsy-aphasia spectrum disorders

    Question: when were other causes identified - perinatal stroke, cortical malformation, other brain injuries, immune system

    2010s to present
    New names

    Earlier names like ESES and CSWS were about what the EEG pattern looked like.
    But they didn’t always match the impact in children.

    Newer terms focus on how the child is learning and developing in their day-to-day life.
    Common names today:

    • EE-SWAS - used when a child develops typically at first, then loses or slows skills

    • DEE-SWAS - used when there are already differences in a child’s development, and epilepsy adds further impact.

    Proposed classification: Syndromes in Children

    2020s
    Brain networks and connections

    The focus is now moving beyond seizures and EEG patterns.

    Newer research suggests DEE-SWAS is not just about abnormal activity in one part of the brain. Changes in how brain networks develop and work together over time may help explain changes in learning and development.

    Developmental and epileptic encephalopathy with spike–wave activation in sleep: From the ‘functional ablation’ model to a neurodevelopmental network perspective

  • What the research says

    A recent paper, Rebuilding the Tower of Babel: The Current Landscape and Emerging Opportunities in DEE-SWAS, shows that:

    • There is still no global agreement on how to diagnose DEE-SWAS.

    • The main marker used is the spike-wave index (SWI), measured on an EEG. But experts do not agree on how to use it.

    • There is no consistent cut-off for how much of sleep must be affected. There is also no clear evidence that one number is correct.

    “The historical 85% cutoff has been predominant, but proposed guidelines in 2009 offered a lower cutoff of ≥50% in NREM sleep. Some groups utilize a 25% cutoff.”

    • There is also no standard way to calculate SWI. Different clinicians use different methods, which can give different results.

    • There is no clear agreement on what SWI actually means in real life, or how well it reflects what is happening to the child.

    Tower of Babel idea

    The title of the paper uses the story of the Tower of Babel.

    In the story:

    • People are trying to build something together

    • But they suddenly speak different languages

    • They can no longer understand each other

    • The project breaks down into confusion.

    In this paper, Tower of Babel means:

    People are using different terms, definitions and methods, so they cannot clearly communicate or move forward.

    Why this matters for families

    The lack of agreement about SWI (for example 85%, 50% or 25%) can affect whether a child:

    • is diagnosed

    • receives treatment

    • is monitored closely

    • is seen as having a serious condition.

    As one paper states:

    “Due to the lack of an established electroclinical phenotype, there has been no standardization of therapy.”

    • The same child could be diagnosed in one clinic, and not in another, based only on how SWI is measured or interpreted.

    • A child may be diagnosed with DEE-SWAS when their SWI is above a certain level. But if it drops below that level, they may no longer be considered to have it.

    This can happen even if:

    • thinking and learning are still affected

    • cognitive difficulties continue

    • behaviour and emotional regulation are still impacted

    Questions this raises

    • How much do these cut-offs reflect a child’s needs - and how much do they reflect what each health system can support?

    • What happens to children who fall just below a cut-off, but are still struggling?

    What families experience

    Families may face:

    • different answers from different clinicians, with no clear way to resolve them

    • long delays before changes are recognised or acted on

    • ongoing learning and behavioural difficulties without a clear diagnosis

    • access to care and support that depends on cut-offs, not need.

    Parents and carers often have to advocate again and again just to have concerns taken seriously.

    This comes with a real cost in time, energy and emotional load.

    Access also depends on where you live

    Where a child lives can affect the care they receive.

    A child may be seen by:

    • a neurologist with deep experience in developmental and epileptic encephalopathies

    • or a clinician who has rarely if ever seen DEE-SWAS.

    The bottom line

    The paper makes this clear:

    We still don’t have a shared and reliable way to define, measure and diagnose DEE-SWAS.

    Until there is global agreement on SWI:

    • diagnosis will continue to vary

    • decisions will differ between clinicians and services

    • Children may live with lifelong effects from decisions made - or not made - at critical times.

    • Families will continue to carry deep uncertainty that affects their child’s care, future planning and daily life.

  • Developmental and Epileptic Encephalopathy with Spike–Wave Activation in Sleep (DEE-SWAS) is an umbrella term for a rare type of childhood epilepsy, with varying presentations, causes and outcomes.

    • It affects around 1 in 200 children with epilepsy.

    • It usually starts between ages 2 and 12, most often around 4 to 5 years old.

    Children can lose previously learned skills, or their development may slow or stop, meaning they are not gaining new skills as expected.

    This is linked to unusual brain activity during sleep.

    More information

    If you’re looking for more detailed medical information about DEE-SWAS, these pages may help.

    They can be technical, but they provide more in-depth explanations of diagnosis, EEG patterns and treatment.

  • The less the environment around a child can adapt to their changing needs, the harder life becomes.

    Impact on learning, connection and participation

    Common challenges families talk about include:

    Cognitive

    • Regression in thinking, problem-solving and memory

    • Difficulty learning and retaining new information

    • Impaired attention span and focus

    • Poor planning and decision making (executive function)

    • Slowed processing speed.

    Language and Communication

    • Delayed or halted speech

    • Loss of previously acquired words or sentences

    • Difficulty understanding spoken language (receptive language)

    • Difficulty expressing thoughts verbally (expressive language)

    • Limited vocabulary

    • Trouble with articulation and clarity of speech

    • Social communication challenges (e.g conversations, social cues)

    Emotional wellbeing

    • Hyperactivity or impulsiveness

    • Mood swings, anxiety, depression

    • Difficulty in emotional regulation (e.g., sudden outbursts)

    • Social withdrawal and lack of interest in social interactions

    • Aggression or irritability

    • Repetitive behaviours or routines

    • Difficulty adapting to routine changes

    • Reduced ability to express emotions.

    Movement and coordination

    • Coordination and balance difficulties

    • Delay or loss of gross motor skills (e.g., walking, running, jumping)

    • Fine motor difficulties (e.g., writing, buttoning clothes)

    • Tremors or abnormal movements

    • Muscle weakness or stiffness (hypertonia)

    • Ataxia (uncoordinated movements)

    • Gait abnormalities (e.g., walking difficulties, unsteady walking).

    Seizures

    • Subclinical seizures in sleep, especially in slow wave (deep) sleep (spike-and-wave activity)

    • Subclinical seizure activity in the waking hours

    • Occasional or frequent clinical seizures, including visible (e.g., tonic-clonic, absence) both day and night

    Toileting and continence difficulties

    • Bedwetting

    • Accidents in the day.

    Sensory and Perception

    • Sensory processing(hypersensitivity or hyposensitivity)

    • Sensory overload or under-reactivity (e.g., to sound, light, touch)

    • Difficulty with spatial awareness and body positioning

    • Impaired vision or hearing processing (e.g., trouble interpreting visual or auditory stimuli).

    Social and Interactive

    • Difficulty forming and maintaining friendships

    • Struggles with peer relationships and social integration

    • Lack of interest in group activities

    • Trouble understanding or responding to social cues (e.g., tone of voice, facial expressions)

    • Isolation or avoidance of social situations

    • Reduced ability to engage in age-appropriate play or interactions

    Sleep

    • Sleep disturbances (e.g., trouble falling asleep, frequent waking)

    • Irregular sleep habits (e.g., staying up late or waking up too early)

    • Sleep apnoea or irregular breathing patterns during sleep

    • Restlessness or hyperactivity at night

    • Poor sleep quality despite adequate hours of sleep.

    Co-existing conditions

    • Intellectual disability (ranging from mild to severe)

    • Autism spectrum disorder (ASD)

    • Attention deficit hyperactivity disorder (ADHD)

    • Cerebral palsy

    • Speech and language disorders

    • Sensory processing disorders

    • Sleep disorders (e.g., night terrors, insomnia).

  • To come

Making sense of it
(for yourself and others)

  • The brain of a DEE-SWAS child is a library without a librarian.

    Picture the brain as a library – a place where books (representing thoughts, memories, and knowledge) are carefully stored and organised. Normally, each night, as we sleep, the brain works like a diligent librarian – sorting, storing, and making sure everything is in its right place.

    But in the case of Developmental andEpileptic Encephalopathy with Spike-Wave Activation in Sleep (DEE-SWAS), the process goes awry. Imagine the librarian doesn't turn up for work. Without their organisation, the books get left scattered all over the place. In the brain, this translates to the spike-wave discharges disrupting sleep, preventing the brain from properly organising and consolidating memories and learned information.

    The result? Just like a library with books in chaos, the brain’s ability to store, retrieve, and build on knowledge is compromised. This leads to cognitive and developmental challenges, affecting learning, memory and overall brain function.

    In short, DEE-SWAS is like a library without a librarian during crucial sleep periods – the brain simply can’t get its act together, and the outcome is a disorganised, inefficient cognitive system.

    This concept is something that stuck with me that a parent in an online support group shared. If you read this, and that person is you, please let me know so I can credit you for the idea.

  • It can feel like a child is carefully knitting something during the day in their mind. Stitch by stitch, they are building skills, memories and understanding.

    But overnight, something begins to pull at the yarn… quietly undoing what was learned that day.

    Some nights only a few stitches loosen. Other nights, whole sections of hard work are undone.

    By morning, the knitting is no longer what it was when last left. Parts may need to be repaired, or may be gone altogether.

    Each child’s knitting pattern is different, and what unravels, and how much, is not the same for everyone.

    This concept is something that stuck with me that a parent in an online support group shared. If you read this, and that person is you, please let me know so I can credit you for the idea.

  • Imagine trying to sleep while someone repeatedly flicks the lights on and off in your room. Just as you drift off, the light snaps on again. Then off. Then on.

    This continues for hours.

    By morning, you haven’t truly rested. You might feel irritable, confused, slow to respond, or unable to think clearly.

    Now imagine this happening night after night, for months or years.

    This is one way to understand what disrupted sleep in DEE-SWAS can feel like for a child.

    This concept is something that stuck with me that a parent in an online support group shared. If you read this, and that person is you, please let me know so I can credit you for the idea.