Idiopathic encephalopathy related to status epilepticus during slow sleep (ESES) as a "pure" model of epileptic encephalopathy. An electroclinical, genetic, and follow-up study.
OBJECTIVE
The objective of the study was to investigate electroclinical and neuropsychological features, genetic background, and evolution of children with idiopathic encephalopathy with status epilepticus during slow sleep (ESES), including Landau-Kleffner syndrome (LKS).


MATERIAL AND METHODS
All children diagnosed with idiopathic ESES at the Danish Epilepsy Centre between March 2003 and December 2014 were retrospectively reviewed. Repeated 24-hour electroencephalography (24-h EEG) recordings, neuropsychological assessments, and clinical-neurological evaluation were performed throughout the follow-up in all patients. In 13 children, genetic investigations were performed.


RESULTS
We collected 24 children (14 males and 10 females). Mean age at ESES diagnosis was 6 years, and mean ESES duration was 2 years and 7 months. Twenty-one children had epileptic seizures. Three children had LKS. Topography of sleep-related EEG epileptic abnormalities was diffuse in 3 subjects, hemispheric in 6, multifocal in 9, and focal in 6. During the active phase of ESES, all children presented with a heterogeneous combination of behavioral and cognitive disturbances. In 14 children, a parallel between severity of the clinical picture and spike-wave index (SWI) was observed. We could not find a strict correlation between the type and severity of neurobehavioral impairment and the side/topography of sleep-related EEG discharges during the active phase of ESES. At the last follow-up, 21 children were in remission from ESES. Complete recovery from neurobehavioral disorders was observed in 5 children. Genetic assessment, performed in 13 children, showed GRIN2A variant in two (15.4%).


SIGNIFICANCE
Our patients with idiopathic ESES showed a heterogeneous pattern of epileptic seizures, neurobehavioral disorders, and sleep EEG features. Only one-fourth of children completely recovered from the neuropsychological disturbances after ESES remission. Lack of correlation between severity/type of cognitive derangement and SWI and/or topography of sleep EEG epileptic abnormalities may suggest the contribution of additional factors (including impaired sleep homeostasis due to epileptic activity) in the neurobehavioral derangement that characterize ESES.
['Pavlidis|Elena|E|', 'Møller|Rikke S|RS|', 'Nikanorova|Marina|M|', 'Kölmel|Margarethe Sophie|MS|', 'Stendevad|Pia|P|', 'Beniczky|Sandor|S|', 'Tassinari|Carlo Alberto|CA|', 'Rubboli|Guido|G|', 'Gardella|Elena|E|']
D000293:Adolescent D017668:Age of Onset D001927:Brain Diseases D002648:Child D002653:Child Behavior Disorders D002675:Child, Preschool D003072:Cognition Disorders D004569:Electroencephalography D005260:Female D005500:Follow-Up Studies D006801:Humans D007223:Infant D018887:Landau-Kleffner Syndrome D008297:Male D009483:Neuropsychological Tests D016194:Receptors, N-Methyl-D-Aspartate D012189:Retrospective Studies D000077310:Sleep, Slow-Wave D013226:Status Epilepticus D016896:Treatment Outcome
Status epilepticus Slow sleep ESES Epileptic encephalopathy Sleep homeostasis