Influence of weather on seizure frequency — Clinical experience in the emergency room of a tertiary hospital

Abstract

Introduction: Some patients with epilepsy identify weather as a typical seizure trigger. However, it is yet to be confirmed. Thus, we aimed to evaluate possible relationships between daily meteorological conditions and the daily incidence of seizures. Methods: This was a retrospective single center study that included adult patients who were admitted to the emergency room of a tertiary hospital in Lisbon, with a seizure, between January and December 2015. The influence of temperature, atmospheric pressure, relative humidity, wind, precipitation, sunlight duration, and the seasons on seizure frequency was evaluated. Results: Three hundred seven seizure episodes were included (from 286 patients) in a total of 365 days, 117 (38.1%) first unprovoked seizures and 190 (61.9%) with previous seizure episodes. There were 82 days with higher incidence of seizures (≥2) and 171 days without seizures. We found a statistical significant relation between lower ambient temperatures, higher atmospheric pressure, and higher maximum humidity with days with two or more seizures. We also found a statistically significant higher incidence of seizures in the winter days (p-value: 0.001) and in days with lower daylight duration (10.8 vs. 12.7 h; p-value: 0.0001). With the exception of humidity, these findings remained true when analyzing the subgroup of patients with previous seizures, but there was no significant difference in the subgroup of first unprovoked seizures. Conclusions: Our results support the possible influence of the weather on seizure frequency in the overall admissions of the emergency department of a tertiary hospital. In particular, these findings suggest that winter conditions, such as, lower ambient temperatures, higher atmospheric pressure, higher humidity, and reduced sunlight exposure, may have impact in the occurrence of higher incidence of seizures in patients with epilepsy.

Cues for seizure timing

“…Cyclical but irregular changes in weather, including barometric pressure, external temperature, and air humidity, may play an additional role in modulating the risk of seizures. Seizures are typically thought to occur on “dull gray days” but do not strictly synchronize with weather patterns 8,27–29 . Solar storms, tidal cycles, and other celestial phenomena often have cyclical behaviors, but seizures do not synchronize to external cues at these timescales (Figure 2).…”

“…The existence of endogenous circannual modulation of cortical excitability was also suggested by experiments on mice kept in a constant environment 34–36 ; however, longitudinal assessment in the same animal was lacking. Epidemiological cross‐sectional data, such as admission rates to emergency departments or seizure counts on the neurology ward, suggest that seizure rates tend to increase in winter 29,37,38 (but see 39 ) across patients, with possible contribution from cold weather, 28,29 daylight duration, 37 and seasonal illnesses leading to febrile seizures in children 40 . Some authors have even speculated that light therapy, effective in the treatment of seasonal depression, could be an add‐on approach in epilepsy to “smooth out some of the seasonal peaks in seizure frequencies.” 37,41 …”

Air Pollution and Hospital Admission for Epilepsy in Kerman, Iran

“…Several studies have shown that meteorological factors such as temperature are associated with hospital admissions for epilepsy attacks (3,(11)(12)(13)(14), therefore we adjusted for average daily temperature and relative humidity. The degree of freedom (df) for the smoothers is determined with Generalized Cross Validation (GCV) and by using the mgcv package in R software.…”

From Precision Metapharmacology to Patient Empowerment: Delivery of Self-Care Practices for Epilepsy, Pain, Depression and Cancer Using Digital Health Technologies

“…Precision digital interventions can be adjusted for stressful or traumatic events (personal and family accidents, wildfires) which could trigger additional anxiety and/or depression (Graham et al, 2019). Since atmospheric conditions can impact people with epilepsy (Xu et al, 2016;Brás et al, 2018;Chang et al, 2019), cardiovascular diseases (Stewart et al, 2017), arthritis (Savage et al, 2015), or seasonal affective disorders (Wirz-Justice, 2018), digital therapy can include algorithms which take into account weather forecast. These examples illustrate a unique potential of digital health technologies to optimize interventions based on predictability of seasonal factors and weather forecast.…”