Epileptic seizure cycles are robust, patient specific, and more widespread than previously understood, according to a recent study, which suggests that these seizures align with the accepted consensus that most epilepsies have some diurnal influence. This retrospective cohort study used the 2 most comprehensive databases of human seizures (SeizureTracker [USA] and NeuroVista [Australia]) and analytic techniques from circular statistics to analyze patients with epilepsy for the presence and frequency of multi-temporal cycles of seizure activity. Researchers used data from 12 people from the NeuroVista study and 1,118 patients from the SeizureTracker database. They found:
- At least 891 (80%) of total patients in the SeizureTracker cohort and 11 (92%) of total patients in the NeuroVista cohort showed circadian (24-hour) modulation of their seizure rates.
- In the NeuroVista cohort, patient 8 had a significant cycle at precisely 1 week, patients 1 and 7 others also had approximately 1-week cycles, and patients 1 and 4 had 2-week cycles.
- In the SeizureTracker cohort, between 77 (7%) and 233 (21%) of total patients showed strong circaseptan (weekly) rhythms, with a clear 7-day period.
Karoly PJ, Goldenholz DM, Freestone DR, et al. Circadian and circaseptan rhythms in human epilepsy: A retrospective cohort study. [Published online ahead of print September 12, 2018]. Lancet Neurology. doi:10.1016/S1474-4422(18)30274-6.