Clinical Research Assistant McMaster University Hamilton, Ontario, Canada
Rationale: The active epileptic process in encephalopathy associated with electrical status epilepticus in sleep (ESES) contributes to the neurocognitive impairment. The aim of treatment for this age dependent epileptic encephalopathy is to improve neurocognitive outcome; however, there is limited prospective data to support the hypothesis that successful treatment results in improved neurocognitive outcomes. Therefore, we explored the relationships between multiple cognitive outcomes measured using standardized neuropsychological tests and changes in sleep EEG pattern as a result of treatment of ESES. Methods: Data came from a prospective cohort of children (aged 4-12 years), newly diagnosed with ESES and followed for one year. The primary cognitive outcome was compsite IQ; other cognitive measures included verbal and nonverbal IQ, language, and visuomotor construction. Change in sleep spike wave index (sSWI) from baseline to follow-up, and an aggregate sleep EEG score (ASES) at follow-up were used to predict cognition at follow-up, while adjusting for baseline cognition. The ASES grade (Grade 1-8) was based on both sSWI and the distribution of epileptiform discharges. Results: Twenty-one eligible children (16 male; mean age, 7.73 years, SD: 1.95) were followed for a median period of 1 year (SD: 0.12; range, 0.91-1.39 years). The sleep EEG pattern was significantly associated with Verbal IQ but not with any other cognitive outcome. A 50% deterioration in sSWI between baseline and follow-up and a one-grade deterioration in ASES were associated with a 4.26 (95% CI: 0.27, 8.25; p=.038) and 1.35 (95% CI: 0.02, 2.68; p=.047) point increase in Verbal IQ, respectively, though this change was relatively minor and not clinically meaningful. Change in sSWI or ASES was not associated with composite IQ (B=3.03, 95% CI: -3.15, 9.19, p=0.32 and B=1.03, 95% CI: -1.01, 3.07, p=0.30). Conclusions: The sleep EEG pattern was not found to be meaningfully associated with cognitive outcomes. It will be important for these results to be replicated by larger subsequent studies and over the long-term. Funding: Please list any funding that was received in support of this abstract.: The study was funded by Ontario Brain Institute and Hamilton Health Sciences Foundation.
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