Abstracts

Electrical status epilepticus in slow sleep (ESES) is characterised by spike, polyspikeand wave discharges occurring during at least 85% of slow wave sleep (SWS). In association with these EEG abnormalities global and selective neuropsychological regression and motor impairments can occur. Increasing awareness that we were diagnosing this condition more frequently recently led us to undertake an audit to explore the patterns of ESES in our clinic populatation. We wanted to identify the prevalence of ESES, underlying etiologies or risks factors, spectrum of clinical presentations, assess treatments, clinical evaluation methods and long term outcome.
The cohort was identified by reviewing all recordings from the previous five years period exhibiting sleep accentuation of epileptiform activity. Those who fulfilled the criteria for ESES were identified. Also included were children whose epileptiform activity occupied 60-85% of SWS if accompanied by a history of regression. Children in nonconvulsive status day and night were excluded. Pre and post treatment evaluation consisted of neurodevelopmental,neuropsychological, school, speech and language therapy assessments. Response to treatment was defined as a measurable improvement on assessment and EEG improvement.
Reports of 2,240 sleep EEG were revieved, 144 (6.4%) showed accentuation of epileptiform activity in SWS.
30 / 2,240 (1.3%) met our extended criteria for ESES. Age at diagnosis ranged from 18/12 -15 yrs mean 6 yrs, median . Age range at presentation with seizures was 1/12 -11.5yrs. ESES was identified at the time of diagnosis of epilepsy in 9 cases. 3 / 30 never experienced seizures.
Indications for considering ESES were cognitive / behavioural / developmental / communication regression or acquired motor problems.
13 / 30 had structural brain abnormalities,12 / 13 had a signficant perinatal event (prematurity, intraventricular haemorrhage)and neonatal seizures, 5/13 have periventicular leukomalcia without motor deficit, 2/13 had a mild head injury prior to onset of ESES. 7/13 reponded to treatment.
8 / 30 cryptogenic partial seizures. 2 / 8 responded to treatment.
6 /30 polymorphous epilepsy. 1 / 6 responded to Rx.
3 / 30 communication disorder 1 / 3 responded.
Teatments used were benzodiazepines (clobazam, nitazepam)20/30, steroids 20/302/30, valproate, Ketogenic diet 1 / 30, surgery 1 / 30
The prevalence of ESES in our clinic population was 1.3% which is higher than previously reported. There is a spectrum of underlying aetiologies, 43% of the cohort had a structural brain abnormality. This later group demonsrated the best response to treatment.ESES can present in teenage years. In most children ESES was refractory to treatment and led to progressive loss of skills however ESES can be a reversible cause of functional deterioration in certain groups. It is essential to consider ESES as a treatable cause for loss of skills in children with acquired or developmental brain lesions.
[Supported by: Nil]