continuous spike and wave during slow wave sleep(CSWS) was first described by patry. The syndrome is characterized by continuous spike and wave activity during non-REM sleep and is sometimes called as “Epilepsy with electrical status Epilepticus during slow sleep” (ESES ). Onset ranges from 1-12 years peak age around 8 years. 2/3 of patients normal neurologically before onset. In time most patients have frequent seizures generalized tonic clonic , atypical absence and atonic also have a significant decline in IQ with deterioration in language, impaired memory , reduced attention span, and behavioral changes with aggression or psychosis epileptiform activity consists of generalized slow 1.5 to 2.5HZ spike wave as well as focal or multifocal spikes, which are sporadic in the waking state. In sleep, spike-wave bursts become nearly continuous(CSWS pattern) , occupying more than 85% of the total NON-REM sleep time . The csws pattern persists for one to several years. Similar to LKS, the EEG then tends to normalize and seizures remit spontaneously in most patients. However recovery of neurological deficit and behavior is often incomplete and about half of the patients remain profoundly impaired.

1. Continuous spike and wave during
slow wave sleep(CSWS)
08/10/20

2. Introduction
• continuous spike and wave during slow wave sleep(CSWS) was first described
by patry.
• The syndrome is characterized by continuous spike and wave activity during
non-REM sleep and is sometimes called as “Epilepsy with electrical status
Epilepticus during slow sleep” (ESES ).
• Onset ranges from 1-12 years peak age around 8 years.
• 2/3 of patients normal neurologically before onset. In time most patients
have frequent seizures generalized tonic clonic , atypical absence and atonic
also have a significant decline in IQ with deterioration in language, impaired
memory , reduced attention span, and behavioral changes with aggression or
psychosis epileptiform activity consists of generalized slow 1.5 to 2.5HZ spike
wave as well as focal or multifocal spikes, which are sporadic in the waking
state.
• In sleep, spike-wave bursts become nearly continuous(CSWS pattern) ,
occupying more than 85% of the total NON-REM sleep time .
• The csws pattern persists for one to several years. Similar to LKS, the EEG
then tends to normalize and seizures remit spontaneously in most patients.
• However recovery of neurological deficit and behavior is often incomplete
and about half of the patients remain profoundly impaired.

3. What is epileptic encephalopathy with continuous spike and
wave during sleep?
• This epilepsy is also known as CSWS or epilepsy with continuous spike-wave during slow wave
sleep.
• This syndrome is a very rare form of epilepsy, affecting 1 out of 200 (0.5%) children with
epilepsy.
• Children can be developing normally before the onset of CSWS.
• Boys seem to be affected more often than girls.
• The cause of CSWS is often found to be brain malformations (when an area of brain forms
differently at birth), genetic variant, or metabolic conditions.
• Seizures begin first, followed by a slow cognitive decline that often is not noticed by
caregivers at first. Types of cognitive problems depend on where abnormalities are found in
the brain.
• If an electroencephalogram (EEG) shows abnormalities in the frontal lobes, behavioral
problems, such as attention deficit hyperactivity disorder (ADHD), aggression, or impulsivity,
are more common.
• If abnormalities are more commonly seen on an EEG in the posterior region of the brain
(back of the head), language or other cognitive abilities may be impaired.

4. What do seizures in this syndrome look like?
• The most common seizure type seen in CSWS is focal motor seizure (only
one part of the body is affected).
• Focal seizures can progress to affect both sides of the brain. When this
happens, the seizure is called a bilateral seizure and looks like tonic-
clonic seizures or convulsions.
• Other seizure types include absence (staring), atypical absence,
and atonic (drop attack) seizures.
• Seizures usually happen during sleep.

5. How is this syndrome diagnosed?
• An EEG (electroencephalogram) is needed to diagnose CSWS.
– In many instances, a prolonged EEG that includes sleep or video
EEG (overnight admission to the hospital) is also needed.
– The EEG in children with this epilepsy syndrome is abnormal, especially as
they enter sleep.
– The spike discharges seen in CSWS tend to become much more frequent
during sleep as compared to wakefulness.
– Almost continuous slow-spike-wave is seen during the slow sleep cycle. Your
physician might use the term ESES, which stands for electrical status
epilepticus during slow sleep.
– These EEG changes may happen in more than 85% of the child’s sleep time.
The EEG changes improve during the REM sleep cycle.
• Genetic and metabolic tests may be ordered.
• MRI (magnetic resonance imaging) scans can be normal, but they are
needed to see if a structural problem in the brain is present.

6. How is epileptic encephalopathy with continuous spike and
wave during sleep treated?
• Medications often used are steroids or high dose diazepam at night. Other
medications that have been used to treat this epilepsy syndrome
include clobazam (Onfi), ethosuximide (Zarontin), valporic
acid (Depakote/Depakene), acetazolamide (Diamox),
and levetiracetam (Keppra). Often, more than one medicine is used at
once.
• Medications can be used together or by themselves, depending on what
works for each child.
• If seizures persist despite medication, a surgery called multiple subpial
transections may be done. This type of surgery makes multiple small cuts
in the brain cortex where the seizures begin.

7. What is the outlook for people with this syndrome?
• Children may be developing normally when seizures first start.
A progressive decline in cognitive and behavioral functioning
starts up to 1-2 years later.
• Children with CSWS may improve during the teenage years.
Seizures often improve or stop and cognitive and behavioral
functioning may get better.
• While cognitive and behavioral functioning may improve,
rarely do children return to normal functioning and can be left
with severe impairment.
• For some children, the abnormalities on EEG may continue
into the adult years.

12. References
Practical guide for clinical neurophysiologic testing EEG.1st edition by Thoru Yamada,MD and
Elizabeth Meng, BA, REEGT/EPT
https://www.epilepsy.com/