Circannual Clustering of Status Epilepticus with Increasing Daylight After the Winter Solstice
Abstract number :
3.392
Submission category :
16. Epidemiology
Year :
2023
Submission ID :
934
Source :
www.aesnet.org
Presentation date :
12/4/2023 12:00:00 AM
Published date :
Authors :
Presenting Author: Marcus Ng, BMSc, MD, FRCPC, CSCN(EEG) – University of Manitoba
Tony Zhang, MD – Auckland District Health Board; Darion Toutant, BSc – University of Manitoba; Milena Pavlova, MD – Brigham and Women's Hospital / Harvard Medical School; Peter Bergin, MD, ChB – Auckland District Health Board; Mark Quigg, MD, MS, FAES, FANA – University of Virginia
Rationale: Circannual patterns of status epilepticus (SE) in communities near Earth’s poles best test the hypothesis that SE susceptibility varies with light exposure because these communities are routinely subject to large changes in annual light exposure, which may result in changes to daily sleep time.
Methods: Given absence of permanent Antarctic human habitation, we compared northern polar hemispheric (n=117, 2009-2020) circannual SE occurrence in Kivalliq, Canada (latitude 62.8°N) to that in the southern hemisphere (n=367, 2015-2016) at Auckland, New Zealand (latitude 36.9°S). We used MATLAB to calculate the mean resultant length (MRL) of circannual data based on SE frequency per month, week, or day of each year. The MRL is equivalent to the phase locking value (PLV) at a static interval. We also conducted Rayleigh’s test in MATLAB using the CircStat toolbox to assess for statistical departure from circular uniformity with significance at p≤0.05.
Results: Both regions experienced significant circannual SE peaks during the increasing daylight phase after each region’s respective winter solstice. Northern hemispheric circannual SE occurrence in Kivalliq, Canada had a circannual peak (MRL 0.17) after the winter solstice in April on monthly (p=0.03), weekly (p=0.04), and daily (p=0.04) analyses. Southern hemispheric circannual SE occurrence in Auckland, New Zealand had a circannual peak (MRL 0.14) after the winter solstice in July on monthly (p=0.0008), weekly (p=0.001), and daily (p=0.001) analyses.
Conclusions: Our study demonstrates that cumulative effects of increasing light exposure can mediate SE susceptibility. Future studies into light-induced circannual seizure provocation should include more global sites across different latitudes with matched antipodal geographies.
Funding: None
Epidemiology