Weather patterns and occurrence of epileptic seizures

Sanja Tomasović,Josip Sremec,Vedran Ostojić,Zurap Raifi,Koraljka Bačić Baronica,Dunja Plačko-Vršnak,Nada Tomić Sremec,Jelena Košćak Lukač,Krunoslav Mikec,Lidija Srnec,Gordana Sičaja

doi:10.1186/s12883-021-02535-8

Abstract

BackgroundThe results of various studies that have so far evaluated the influence of meteorological conditions on seizures are often divergent. No studies have been performed so far that evaluate the possible correlation between the occurrence of seizure-related events, surface and upper level atmospheric conditions and biometeorological forecasts. The aim of this study is to investigate those interactions.MethodsRecords of “Sveti Duh” University hospital, Zagreb, Croatia between January 2016 and May 2020 were analysed in order to determine number of patients per day who were assessed through Emergency room because of a recent epileptic seizure. The dates were assessed for surface and upper level atmospheric conditions and biometeorological forecasts. Analyses of these factors were performed for two consecutive days preceding that day, the day of seizure, as well as for the following day. Data was analysed using chi-squared test, Mann-Whitney U-test or Kruskal-Wallis test (with Conover’s test for post-hoc analyses), depending on variable type. Additionaly, logistic regression was used to study effects of variables on seizure occurrence. Statistical significance was set to p < 0.05.ResultsResults showed significant difference between the numbers of patients with seizure depending on upper level type on the following day. We also observed fewer daily patients with seizures when the synoptic situation on the following day was high pressure field then when it was low pressure or non-gradient pressure field (observed just during the colder part of the year), which was supported in our regression analyses. A greater frequency of seizures was observed if the biometerological prognosis was deemed unfavourable on the following day. Furthermore, our results showed significantly larger proportion of days with seizure patients in warmer, than in colder days of the year.ConclusionsAll of the analyzed weather-related parameters seem to be associated with daily numbers of seizures on the previous day. The reason behind this phenomenon is uncertain; however, the results indicate that weather patterns have a certain influence on patients with epilepsy, but are not yet fully understood or adequately appreciated.

Highlights

The results of various studies that have so far evaluated the influence of meteorological conditions on seizures are often divergent
The differences stem from distributions of days with non gradient upper level weather types (for a more detailed analysis we could discriminate non gradient field in ridge (NG-R) and in trough (NG-T) – as descripted in Table 1), which are more common in warmer months, while trough (T), as well as Front side of the trough (SWS), Back side of the trough (NWS), SES, Northeasterly flow (NES), NS, and SS types are more common in colder months
There were no differences regarding the number of patients with seizures between days with particular upper level weather types (p = 0.433, Kruskall-Wallis test), as well as in respect to those weather types on the day (p = 0.577, Kruskall-Wallis test) or 2 days (p = 0.982, Kruskall-Wallis test) earlier

Summary

Introduction

The results of various studies that have so far evaluated the influence of meteorological conditions on seizures are often divergent. Meteorological and climate factors, both short and long-term, In neurology, surface meteorological conditions such as mean daily temperature, humidity, atmospheric pressure and wind conditions, as well as seasonal changes, have been associated with the occurrence of disorders with paroxysmal onset: seizure related disorders, as well as Tomasović et al BMC Neurology (2022) 22:33 diseases of vascular origin (haemorrhagic and ischemic stroke, subarachnoid haemorrhage), the results of various studies for the latter are often heterogeneous and conflicting [8,9,10,11,12]. Unstable weather conditions correlate with epileptiform changes in electroencephalography (EEG) studies of patients with epilepsy [24]

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