Abstracts

Rationale: The diagnosis of electrographic status epilepticus of sleep (ESES) is established based on the presence of continuous spike wave (SW) activity during at least 85% of non-REM sleep (NREMS) in association with motor and neuropsychological deterioration independent from the primary epileptic disorder (ILEA, 1989). However, assessment of clinical improvement following therapeutic intervention is often based on subjective parental reporting. Intra-observer variability during subsequent EEG monitoring to document continuing percentage of sleep disrupted by SW activity may also make assessment of therapeutic response difficult. Here, we examined the clinical utility of compressed spectral array (CSA) as a tool for assessing the improvement of background SW activity in children with ESES. Methods: 6 children were retrospectively identified in whom EEG was available for CSA prior to and following therapeutic intervention. 5 patients with the diagnosis of ESES were identified. ESES was diagnosed based on clinical criteria described above in association with focal or generalized SW activity during at least 85% of NREMS (Tassinari, 1995). 1 patient with frequent SW activity (60% of NREMS) was included given the concurrent onset of new behavioral and neuropsychological deterioration which improved with normalization of her EEG (<5% SW activity) following treatment with high dose diazepam. 4 children underwent initial in-hospital treatment with oral diazepam (DZP) (1mg/kg, max 40 mg as a first dose). 2 remaining children not initially treated with high dose diazepam were managed with other oral antiepileptic medications. Demographics, clinical features, and EEG findings were reviewed. CSA was compared prior to and following therapeutic intervention and was obtained using MagicMarker (Persyst, Inc, Prescott AZ, U.S.A.) The frequency spectra data were calculated for 2 groups of electrode pairs representing right and left scalp regions combining parasagittal and temporal channels. Results: The mean age of initial seizure onset and diagnosis of ESES was 3.33yrs±2.73 yrs (2F/4M) and 7.14yrs±2.33yrs respectively. Primary epilepsy diagnosis included symptomatic generalized epilepsy in 2 and symptomatic focal epilepsy in 4 patients. Brain MRI was abnormal in 5 patients. Seizures were well controlled in 4 patients with mean duration from last seizure to ESES onset of 2.2yrs±1.74yrs. EEG findings included focal SW activity and generalized SW activity in 5 and 4 patients respectively. The majority (n=5/6) had a sustained clinical and EEG response to therapy. CSA was concordant with the visual interpretation of EEG findings prior to and after medical treatment. CSA also accurately quantified the duration, frequency and lateralization of SW activity in all children. Conclusions: CSA is an efficient, reliable and reproducible method for analysis of the EEG findings seen in ESES. This method provides additional objective information concerning the change in EEG findings over time and is useful in the evaluation of response to therapeutic medical intervention.