Most epilepsies appear to have some diurnal influence, and seizure cycles are patient-specific, robust, and more widespread than previously understood, according to a study published in The Lancet Neurology.
Researchers in this large, retrospective, cohort study used analytic techniques from circular statistics to quantify the prevalence, frequency, and strength of seizure cycles in patients with epilepsy. They collected data from the NeuroVista study (Melbourne, VIC, Australia) and SeizureTracker (United States). Patients from NeuroVista were selected for analysis based on having intractable focal epilepsy and at least 30 clinical seizures. As participants in SeizureTracker are self-selected, patients were chosen for analysis based on having a minimum of 100 seizures. Investigators determined the presence of cycles over multiple time scales using R value (the mean resulting length), and they also determined circular uniformity using the Hodges-Ajne test and the Rayleigh test paired with Monte-Carlo simulations for confirmation.
Of the 1118 SeizureTracker patients, 891