What is developmental/epileptic encephalopathy with spike wave activation in sleep (DEE-SWAS)?
Developmental/epileptic encephalopathy with spike wave activation in sleep (DEE-SWAS) is a rare epilepsy syndrome that affects children aged two to 12 years, with a peak around four to five years of age.
It was previously known as epileptic encephalopathy with continuous spike and wave in sleep (CSWS) or electrical status epilepticus in sleep (ESES).
If a child’s pre-existing neurodevelopment is normal, those patients are referred to as epileptic encephalopathy with spike wave activation in sleep (EE-SWAS). If there is a pre-existing developmental delay, then it is called developmental/epileptic encephalopathy with spike wave activation in sleep (DEE-SWAS).
When language is predominantly affected, some people also use the term Landau-Kleffner syndrome (LKS); it may be considered a subtype of DEE-SWAS.
What are the common symptoms of DEE-SWAS?
An affected child may (EE-SWAS) or may not (DEE-SWAS) have prior normal neurodevelopment.
Usually, the loss of previously acquired skills, such as language, motor abilities or social interaction are noted. Frequently, there may be changes in behaviour, such as hyperactivity, aggression or difficulty with attention. Sometimes, patients may fail to gain new skills with the onset of this syndrome and development “plateaus”.
Not all children with DEE-SWAS also have seizures. When seizures happen, they can be focal, generalized tonic-clonic, absence (typical or atypical) or atonic seizures. Seizures may appear for the first time or may change in frequency, intensity or appearance with the onset of this syndrome.
Learning difficulties and sleep disturbances are often noted.
What are the causes?
The exact cause of DEE-SWAS is not always clear.
Possible causes may include the following.
- Genetic: Several genetic changes have been linked to DEE-SWAS. Common ones include GRIN2A and CNKSR2.
- Structural: Brain malformations, early childhood strokes (especially in the newborn period) or any early brain injury or damage, especially involving the thalamus (located on top of the midbrain).
- Evolution from other epilepsy syndromes: Sometimes, other epilepsy syndromes may evolve into DEE-SWAS, either spontaneously or, rarely, due to medications such as carbamazepine.
How is DEE-SWAS diagnosed?
Diagnosis of DEE-SWAS requires loss of developmental skills or stalling of neurodevelopment with a simultaneous EEG showing a striking finding of marked activation of epileptiform discharges in sleep (when compared to awake state). Seizures are often present but may not be accompanying.
A detailed evaluation by a child neurology doctor or epilepsy specialist is crucial. This usually involves detailed information gathering about a child’s birth history, development and trajectory, behaviour and seizures. Some children may also require a formal neuropsychology evaluation by a psychologist.
A sleep EEG is mandatory to establish the diagnosis. A short awake and sleep EEG (30 to 60 minutes) or a prolonged EEG (e.g., overnight EEG) may be ordered by the treating doctor.
The emergence of classical sleep EEG findings must be correlated in time with the clinical deterioration in form of loss of skills or stalling of development. If there are no changes in the developmental trajectory that correlate to the sleep EEG findings, then a diagnosis of DEE-SWAS cannot be made.
A brain MRI is often ordered (if not already done) to explore the underlying cause.
If a clinical evaluation, EEG and brain MRI fail to reveal a cause, genetic testing may be done.
How is DEE-SWAS treated?
Treatment needs to be individualized to every patient.
Common anti-seizure medications used to treat DEE-SWAS include benzodiazepines (e.g., clobazam, diazepam), steroids (e.g., prednisolone, prednisone, methylprednisolone, dexamethasone, hydrocortisone), valproate, ethosuximide, acetazolamide, sulthiame and levetiracetam. Rarely, immunotherapies such as intravenous immunoglobulin or the ketogenic diet may be considered.
Some medications, such as carbamazepine, oxcarbazepine or phenytoin, should be avoided as they worsen this syndrome.
In carefully selected patients (e.g., patients with stroke or brain malformations affecting one side of the brain), epilepsy surgery may be explored.
Medical management needs to be done along with speech, occupational and behavioural therapies to support development. Collaboration with school teachers to create an Individualized Education Plan is recommended.
What is the long-term outlook for patients with DEE-SWAS?
Patients with DEE-SWAS often improve during their teenage years. Seizures often get better and neurodevelopment may also improve.
Seizures and neurodevelopmental trajectory may often fluctuate during treatment. Often, patients are left with mild to severe cognitive deficits despite treatments.
Early diagnosis with early treatment leads to better outcomes.
Patients often require periodic clinic visits, sleep EEGs and ongoing neuropsychology evaluations.
