Some issues in non-convulsive status epilepticus in children and adolescents with learning difficulties

Individuals with learning difficulties commonly suffer from concomitant conditions; epilepsies constitute up to 35%. The prevalence of epileptic syndromes in learning disabled people is less well documented. Non-convulsive status epilepticus (NCSE) occurs with many epileptic syndromes. It can present with insidious or paroxysmal change of neurovegetative, behavioural, cognitive or affective symptoms which can mistakenly be attributed to other causes. NCSE of generalized epilepsy syndromes can show localizing features and NCSE of localization-related epilepsy can show generalized epileptiform discharge patterns. We reviewed 14 residents' (< 20 years, all learning disabled) EEG recordings in inter-ictal stages and in NCSE and conclude that the current nosological grouping of NCSE does not ensure appropriate categorization in a significant number of cases. We developed a revised NCSE classification: (I) Generalized epileptic syndromes: (a) with no evidence of lateralization inter-ictally or in NCSE; (b) with evidence of lateralization in NCSE only. (II) Localization-related epileptic syndromes: (a) with evidence of lateralization/focal activity in NCSE; (b) with evidence of generalized EEG patterns when in NCSE only; (c) with transient forms: same individual shows generalized and lateralized/focal NCSE activity in different EEGs. We suggest our system be tested in larger studies for its sensitivity, reliability and validity.