The pathophysiological mechanisms of cognitive and behavioral disturbances in children with Landau–Kleffner syndrome or epilepsy with continuous spike-and-waves during slow-wave sleep

Abstract

Epilepsy with continuous spike- and -waves during slow-wave sleep and Landau-Kleffner syndrome are two rare childhood epilepsy syndromes. The underlying pathophysiology remains unknown. The current opinions about epidemiologic risk factors, genetic predisposition, EEG and MEG findings, influence of anti-epileptic drugs, neuroradiology, positron emission tomopgraphy, evoked potentials, auto-immunity and subpial transection are summarized.

Rehabilitation issues in Landau–Kleffner Syndrome

“…All children present with a global language disorder and EEG abnormalities. Clinical seizures are the first symptom of LKS in 60% of cases and a language disturbance is the first symptom in the remainder [6]. Clinical seizures are not necessarily present and never appear in 20-30% of cases [7].…”

“…Non-verbal skills are preserved [7]. In many cases, children present with challenging behaviour often directly linked to deficits in communication [6,15].…”

“…The second stage is a chronic phase, during which mild cases show continuing abnormalities in language and EEG, while more severe cases show further deterioration of language as well as manifestation of behavioural problems, which can be seen in 50-70% of cases [6,9]. These can include attention deficits, hyperactivity, oppositionality, aggression, inappropriate social behaviour, mood problems and hyperkinesia [7,10] and have been found to be relatively independent of the severity of the language disturbance [4].…”

“…Severe behavioural problems have been linked to frontal EEG abnormalities, hypothesized to have spread anteriorly from original foci [12], in a sub-set of children [9]. Severe cases also demonstrate general cognitive decline if the duration of disturbance is long [6]. In addition, social adjustment is affected for obvious reasons [8].…”

“…However, out of more than 300 cases reported, only two have involved sets of siblings and one set of monozygotic twins did not show concordance [20]. Therefore, a currently unknown environmental trigger may be necessary for the condition to manifest [6]. Single cases have been reported of LKS following infection or other insult, although these are rare and most cases are idiopathic [5].…”