Abstracts

Rationale: There are still limited studies on ESES. Most are small case series and majority have looked into ESES with spike wave index occurring >50% of non-rapid eye movement (REM) sleep. We have looked into our ESES population that fits the classic definition with a SW index of more than 85%. Methods: :We retrospectively reviewed patients who were monitored by overnight inpatient video EEG at the Children s National Medical Center from March 2010 to March 2013. Of the video EEGs, 37 showed EEGs with sleep activated spikes at least 50% of the non-REM sleep. Of these 37, 21 had a SW index of > 85%. Medical records were queried for seizure type, etiology, neuroimaging, medical treatment, and seizure outcome. Results: Twenty one (21) patients were found to have spike wave index of >85 %. Age ranged from 5 to 11 years with 12 females and 11 males. Seizure onset was 1 month to 7 years and diagnosis of ESES was at 3 to 10 years old. Seizure type consists of mixed = 1, GTC = 4 (19%), CPS = 13 (61%); atonic = 1; tonic =1. One patient had no seizures but had LKS. Nine (42%) had ADHD and 16 (76%) had cognitive issues. However, only 4 had neuropsychological testing done. Language regression was seen in 4 patients (19%), 2 with an LKS diagnosis. MRI findings were normal in 11 (52%) patients and 3 (14%) had nonspecific findings. Two (9%) had thalamic hemorrhage; and 5 had other abnormalities in the MRI (diffuse brain injury - 1, dysplasia -3; schizencephaly-1 ). Other etiologies include: incontinentia pigmenti (1), chromosomal abnormality (2), septooptic dysplasia (1), and 1 with MELAS. Thirteen out of the 21 (61%) patients became seizure free. Six were either on valproic acid monotherapy or with another medication. Three were on ethosuximide plus one other medication. One patient was on levetiracetam and oxcarbazepine and 1 patient was on diazepam. One became seizure free with sulthiame. Of these 13 patients, follow up EEGs were normal in 6 (46%), 4 had improvement with no ESES but with occasional spike waves, and 1 showed persistent ESES. Two had no follow up EEGs. Two patients had surgery done and remained seizure free with normal follow EEGs. Four out of the 21 patients (19%) had seizure reduction of > 50%. Three showed reduction in the SW index of < 50% and one had persistent ESES. One patient had MELAS but the other three had normal MRI with no clear etiology. Two patients continued to have seizures despite medications with a persistent ESES. Two patients had no follow up EEG done. Conclusions: We have looked into patients with ESES diagnosis with a specific EEG criteria . Majority of patients have complex partial seizures. Two patients showed a thalamic hemorrhage and this was observed in a previous study. Majority of the patients (61%) became seizure free mostly on a valproic acid or ethosuximide. In carefully selected patients, surgery can be an option. There was no clear correlation with etiology and MRI abnormalities with response to treatment. Majority of the patients with improvement in seizures also had improvement in their EEG.