Epileptic encephalopathy with continuous spike-waves during sleep

Epileptic encephalopathy with continuous spike-waves during sleep (ECSWS)
Epileptic encephalopathy with continuous spike-waves during slow-wave sleep (CSWS)

• a spectrum of epileptic conditions best defined by the association of cognitive or behavioral impairment acquired during childhood and not related to another factor other than the presence of abundant interictal epileptiform discharges (IED) during sleep^[2]
• characterised by infrequent nocturnal focal seizures, atypical absences related to secondary bilateral synchrony, negative myoclonia, and atonic and rare generalized tonic-clonic seizures.
• Landau-Kleffner syndrome (LKS) is a particular presentation where acquired aphasia is the core symptom
• LKS and CSWS are said to “describe the clinical epileptic syndromes seen with ESES. There is an overlap between the two syndromes in that patients with CSWS have more global regression and more problematic epilepsy than those with LKS, who had only acquired auditory agnosia and fewer seizures^[3]
• The EEG patterns CSWS and electrical status epilepticus during sleep (ESES) are likely equivalent terms. CSWS is used by some authors, and ESES by others^[4]
• The term “epilepsy with continuous spike and wave during slow sleep” was adopted by the Commission on Classification and Terminology of the International League Against Epilepsy in 1989^[5]
• transition from childhood epilepsy with centro-temporal spikes (CECTS) into LKS and CSWS has been shown to occur particularly when there are atypical signs, high discharge rates, prolonged duration of ESES, cognitive dysfunction, and poor responsiveness to medications^[6].

Electrical status epilepticus during sleep

Patry et al. in 1971^[7] decribed six children in whom sleep induces, night after night and sometimes over a period of many years, a dramatic modification of the EEG, very characteristic of petit mal status but without any clinical accompaniment nor changes in normal sleep patterns. Lasting throughout the whole night, it subsides upon awakening. They proposed to call the phenomenon an “electrical status epilepticus.”

ESES can be divided into symptomatic and idiopathic forms^[4][8]. Symptomatic forms are associated with local structural lesions on MRI in whom ther are hemiclonic, secondarily generalized, and automotor seizures with continuous regional or diffuse epileptiform activity and also marked cognitive disturbances.

The idiopathic form was characterized by early normal development, mostly “rolandic” attacks, atypical absences, negative myoclonus, exclusively diffuse epileptiform activity, cortical subatrophy on MRI, and some cognitive disturbances.

• acquired aphasia^[9]; sensory aphasia followed later by motor aphasia^[10], usually severe and called “epileptic aphasia”^[11]
• cognitive function impairment
• neuropsychological impairment (behaviour problems)
• motor impairment (ataxia, dyspraxia, dystonia, or some unilateral deficit)
• all types of generalized seizures may occur
• improvement in seizures usually is associated with improvement in cognition followiing AED institution

• continuous, diffuse, bilateral spike-waves during slow-wave sleep
• in CSWS EEG foci is predominantly in the frontotemporal or frontocentral areas, whereas in LKS the EEG foci is in the posterior temporal areas^[3]
• in ESES nearly continuous, irregular generalized spike–wave complexes, seen in at least 85% of the sleep record and with minimal abnormalities during wakefulness^[12]
• the bilateral complexes in ESES represent secondary bilateral synchrony^[13][14]

• prednisolone^[15], benzodiazepines^[16], and also levetiracetam^[17] have been found to be effective in patients with CSWS.