Assistant Professor University of California, Los Angeles, Department of Pediatrics Los Angeles, California
This abstract will be presented during a Pediatric Highlights platform session This abstract has been invited to participate in the Better Patient Outcomes Through Diversity poster session
Rationale: Epileptic spasms (ES) most often occur in the setting of West syndrome, though occasional cases occur in older children, usually without hypsarrhythmia. Given that interictal paroxysmal fast activity (PFA) appears to be a prominent finding on interictal EEG among children with ES, we set out to evaluate an unbiased computational method to identify and quantify PFA and use this measure to identify children with ES. Methods: We identified 50 patients with epileptic spasms confirmed by overnight video-EEG, as well as 25 infants who underwent video-EEG to specifically evaluate for suspected epileptic spasms, but were found to have a normal EEG and deemed neurologically normal. In an identical fashion for cases and controls, each EEG was sampled four times (two awake, two sleep) with specific samples selected using a randomization algorithm to mitigate sample selection bias. Artifactual EEG was then excluded using a fully-automated, principal components analysis-based algorithm. Thereafter, we calculated the strength of cross-frequency coupling between gamma (35-70 Hz) and delta (3-4 Hz) activity measured as the modulation index (MI) in wakefulness and sleep as follows: MI for each EEG sample was determined using the mean MI across all EEG channels (except A1 and A2) and MI for each patient (awake or sleep) was defined as the mean of the two samples. We then contrasted awake and sleep MI between cases and controls. Results: In both wakefulness and sleep, gamma-delta MI was substantially higher among cases than controls (P < 0.001 for all comparisons) (Figure 1). This contrast remained highly significant (again, all comparisons P < 0.001) after limiting the analysis to patients without hypsarrhythmia and with statistical adjustment for age at EEG. Conclusions: This study suggests that gamma-delta MI may reliably distinguish between children with and without epileptic spasms, even in the absence of hypsarrhythmia, without the need to record sleep or events suspected to represent epileptic spasms. Further study is needed to validate these findings and evaluate the utility of MI against other computational and clinical EEG measures. Funding: Please list any funding that was received in support of this abstract.: This study was accomplished with support from the Susan S. Spencer Clinical Research Training Scholarship from the American Academy of Neurology, the Pediatric Victory Foundation, the Sudha Neelakantan & Venky Harinarayan Charitable Fund, the Elsie and Isaac Fogelman Endowment, the Mohammed F. Alibrahim Endowment, the Hughes Family Foundation, the John C. Hench Foundation, the UCLA Children’s Discovery and Innovation Institute, and UCB Biopharma.
