Seizure risk may increase with certain weather conditions
Weather is a major risk factor for epileptic seizures, such that exposure to low atmospheric pressure and high relative air humidity may increase epileptic seizure risk whereas high ambient temperatures lower the risk, a study has found.
The retrospective study included 604 adult patients (median age 64 years; 49.5 percent female) admitted to a large university hospital in Central Germany for an unprovoked epileptic seizure between 2003 and 2010. Researchers estimated the effect of atmospheric pressure, relative air humidity and ambient temperature on the onset of epileptic seizures under temperate climate conditions.
A close-to-linear negative association was found between atmospheric pressure and seizure risk. Every 10.7 hPa lower atmospheric pressure increased seizure risk 14 percent in the entire study population by (odds ratio [OR], 1.14; 95 percent CI, 1.01 to 1.28) and by 36 percent among patients with less severe epilepsy treated with one antiepileptic medication (OR, 1.36; 1.09 to 1.67).
A J-shaped association was observed between relative air humidity and seizure risk, with a high relative air humidity of >80 percent increasing the risk by up to 48 percent in the entire study population (OR, 1.48; 1.11 to 1.96) 3 days after exposure.
On the other hand, high ambient temperatures of >20°C demonstrated a protective effect, reducing seizure risk by 46 percent in the overall study population (OR, 0.54; 0.32 to 0.90) and in subgroups, with the greatest effect observed for male patients (OR, 0.33; 0.14 to 0.74).
Epileptic seizures are one of the most common neurologic disturbances in adults, with several external and internal trigger factors including sleep deprivation, sensory stimulation, psychological stress and hyperventilation. Nevertheless, most seizures occur unexpectedly and unpredictably, independent of the aforementioned factors. [Seizure 2014;25:72–79; Epilepsy Behav 2005;6:85–89]
Of note are patient reports of changes in weather as one of the most significant risk factor for seizures. Plausible explanation for this association is the increasing neuronal activity that occurs with increasing temperature or decreasing atmospheric pressure. [Headache 2010;50:1449–1463]
The present data lend support to the perception of many epileptic patients that seizure risk increases with certain weather conditions, researchers said, adding that patients could take precautions in such unfavourable weather conditions to help prevent common seizure-related injuries.
Still, the findings require further replication in different regional climate zones and cohorts before reliable clinical recommendations can be made, they added.