Electrical Status Epilepticus of Sleep (ESES)
Kobe Christensen
ELECTRICAL STATUS EPILEPTICUS OF SLEEP (ESES)
Introduction
Electrical Status Epilepticus in Sleep (ESES) is a condition that is characterized by an EEG pattern of continuous spike and wave discharges during non-REM (NREM) sleep. ESES presents with cognitive decline, likely as a result of almost constant epileptiform activity during sleep which may lead to significant cognitive decline.
Signs & Symptoms
Onset
ESES typically affects children between the ages of 2 and 12 with a peak onset between 4 and 8 years old.
Cognitive Effects
A hallmark of ESES is regression in their development. Normal sleep processes are critical for consolidating memories, processing information, and the ability to learn new skills. Due to the frequent disturbance of sleep, many children with ESES experience a loss of previously acquired skills particularly in language and memory. Some children will experience significant behavior and emotional challenges that may be misinterpreted as ADHD or other behavioral disorders.
Epilepsy
ESES is defined by frequent epileptiform rather than physical seizures though some children may experience absence, atonic, myoclonic, or focal seizure types. Seizure frequency is noted to be heavily correlated with cognitive regression in these patients.
EEG Findings
Characteristic Discharges
The key EEG pattern in the diagnosis of ESES are continuous (or nearly continuous) spike and wave discharges during NREM sleep. These discharges are isolated to NREM sleep, as during wakefulness and REM sleep the pattern may partially or completely disappear.
During NREM sleep, discharges are generally between 1-3 Hz spike and wave discharges that are often generalized, but may appear more focal in some cases. During wakefulness and REM sleep, it is more likely to see discontinuous, focal or multifocal epileptiform discharges. Due to the sleep dependence of ESES, clinical guidelines generally recommend a prolonged EEG capturing multiple sleep cycles to aid in diagnosis.
Spike-Wave Index (SWI)
The SWI is used to measure the percentage of NREM sleep that is marked by epileptiform discharges. For diagnosis of ESES, the SWI is typically >85%, though there is some debate among researchers as different studies have quoted a highly variable range between 25%-85% of NREM sleep being considered ESES.
(Insert photo of ESES when given permission)
Treatments & Prognosis
Antiepileptic Drugs (AEDs)
Commonly used AEDs in the treatment of of ESES include, levetiracetam, valproate and ethosuximide. These medications are not generally given as a monotherapy, but rather together in some type of combination therapy. AEDs generally prove useful as they can decrease the frequency of discharges during sleep, however complete remission is not commonly reached.
Prognosis
In children with ESES, seizures and epileptiform during sleep tend to spontaneously resolve after puberty. However, cognitive decline as a result of ESES typically persists into adulthood. Capturing ESES earlier in life is important to reducing the severity of cognitive decline into adulthood as delayed treatment generally leads to a worse cognitive outcome.
Associated With Landau-Kleffner Syndrome
Landau-Kleffner syndrome is marked by a severe regression of language development and status epilepticus during sleep. EEG in Landau-Kleffner is usually lateralized as opposed to the diffuse nature of ESES. Children with Landau-Kleffner are still referred to as having ESES, and it is important to know that while all Landau-Kleffner patients have a form of ESES, not all ESES patients are diagnosed with Landau-Kleffner syndrome.
Case Study
Scenario
A 5 year old child with no prior medical history is referred to a neurologist due to significant language regression and attention difficulties in school.
EEG Findings
Wakeful EEG showed multifocal sharps suggesting potential epilepsy. Upon falling asleep, the monitoring technician noticed nearly continuous spike and wave discharges with a frequency of 2-2.5 Hz. These discharges abruptly stopped when the patient entered REM sleep, and shortly restarted as the sleep cycle continued. The technician noted that about 90% of the NREM sleep cycle was marked by these continuous epileptiform discharges.
Diagnosis
Electrical Status Epilepticus in Sleep (ESES).
Key Takeaways
- ESES affects children between the ages of 2 and 12, and will spontaneously resolve after puberty.
- EEG during NREM sleep will show nearly continuous 1-3 Hz spike and wave discharges that make up >85% of the non-REM sleep cycle.
- Language regression, cognitive decline, and behavioral challenges are symptoms of ESES.
- ESES is seen in Landau-Kleffner syndrome, though typically in Landau-Kleffner syndrome ESES is only seen unilaterally on EEG.
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