Abstracts

Rationale: Encephalopathy with electrical status epilepticus during sleep (ESES) is the clinical syndrome of epileptic encephalopathy that presents during childhood and consists of epilepsy, developmental regression, and a characteristic electroencephalographic (EEG) pattern of significant sleep-potentiated spike-and-wave activity during non-REM sleep^1,2. Here, we present two children with ESES who initially presented with focal motor rather than cognitive decline. This is an unusual and rare occurrence but it should raise awareness to continue to consider ESES in the differential of focal motor findings in the absence of another plausible etiology and in the absence of cognitive decline.

Methods: Retrospective chart review was performed of two patients at Phoenix Children’s Hospital, AZ. EEGs and MRIs were reviewed where available.

Results: Patient 1 initially presented around age 3.5 years with repetitive jerks and drop attacks. The initial EEG showed recurrent bursts of generalized irregular polyspikes, and slow spike and wave discharges maximal over the central and bi-frontocentral regions. Sleep recording did not show epileptiform activity at that time. Over the next few months, he started experiencing staring episodes and more frequent myoclonic jerks. Along with increased seizures, he developed left hemiparesis and difficulty standing. His weakness worsened and he was eventually unable to walk. Following the motor decline, he began to demonstrate a decline in language skills as well. At this time, repeat continuous EEG monitoring revealed ESES with a spike-wave index of 90% measured over random 3-minute epochs during sleep (Figure 1a). He was treated with a 30-day course of high-dose diazepam at night, which resulted in dramatic improvement in seizure frequency along with resolution of left hemiparesis and improvement in language. Repeat EEG monitoring showed a reduction in spike wave index to 50% during sleep (Figure 1b).

Patient 2 was a female with autism spectrum disorder who was non-verbal with global developmental delays and presented with occasional events concerning for seizures around age 1.5. By age 4, she presented with bilateral lower extremity weakness that rapidly progressed to an inability to walk or stand. She had continuous EEG monitoring which showed ESES with spike-wave index of 78% measured over random 3-minute epochs during non-REM sleep (Figure 2a). She was started on course of nightly diazepam followed by repeat continuous overnight continuous EEG monitoring which showed improvement in spike wave index to 50% during sleep (Figure 2b). She also had complete resolution of bilateral lower extremity weakness and mobility.

Conclusions: A presentation of encephalopathy with ESES with focal motor deficits prior to cognitive deficits has not been previously reported. Although this is a rare occurrence, it may also be an unrecognized and under-detected phenomenon. This case series will highlight the importance of recognizing this atypical pattern.

Funding: Please list any funding that was received in support of this abstract.: This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.