Abstracts

Rationale: Psychogenic non-epileptic seizures (PNES) can mimic epileptic seizures, but in contrast to the latter, are not associated with physiological CNS dysfunction. Missing the diagnosis of PNES may result in unnecessary treatment with anti-epileptic medications with unwanted side effects. Video-electroencephalography (vEEG), the gold standard diagnostic test for PNES, should be performed in all suspected patients. The notion of the effects of lunar cycle on seizure occurrence in patients with PNES has been scarcely studied with mixed results. Furthermore, effects of climate factors on frequency of non-epileptic seizures are not well understood. As such, we aimed to study the influence of lunar phase and climate on the frequency of non-epileptic seizures. Methods: The vEEG report of all patients aged 18-89 year-old admitted to the Epilepsy Monitoring Unit (EMU) at Upstate Medical University from October 2014 to March 2016 was reviewed. Patients with a discharge diagnosis of PNES were included in the study. Patients with mixed epileptic and non-epileptic seizures were excluded. Non-epileptic events, based on their semiology, were categorized as hypermotor (violent and disorganized movements of the extremities, pelvic thrusting, or head movements), hypomotor (altered responsiveness associated with either mild motor or trembling-like activities), or altered sensorium (subjective report of symptoms without impaired consciousness). All seizure occurrences were divided into the four quarters of the lunar cycle for statistical analysis. Events were further analyzed based on various climate factors including ambient temperature and barometric pressure. Results: A total of 50 consecutive patients who met the criteria were included in the study. Among the included patients, 197 individual seizures were recorded. Patient characteristics and baseline vEEG data are summarized in Table 1. Among the reviewed seizures, 44.2% were hypomotor, 34.5% hypermotor, and 21.3% altered sensorium. Total number of seizures in each day showed a weak but statistically significant correlation with the mean daily temperature [Correlation coefficient (CC)=0.220, P=0.029]. When broken up for each type of seizure, the correlation remained statistically significant only for hypermotor seizures (CC=0.250, P=0.046). A slightly stronger reverse correlation was observed between the incidence of hypermotor seizures and barometric pressure (CC=?'0.324, P=0.046). Also, there was a significant increase in overall seizure frequency in lunar first quarter (P < 0.001). This difference was mainly accounted for by hypermotor (P < 0.001) and altered sensorium (P < 0.001) seizures as hypomotor seizure occurrence was not found to be different between lunar phases. Incidence of different seizure types in each lunar phase is plotted in Figure 1. Conclusions: This primary study suggests that climate factors and lunar phase may have an influence on the frequency of non-epileptic seizures, especially in the hypermotor category. In our study the frequency of hypermotor seizures shows a weak but statistically significant correlation with higher ambient temperatures and slightly stronger and reverse correlation with barometric pressure. Hypermotor and altered sensorium seizures are more prevalent in the first quarter of lunar cycle but our data on hypomotor seizures is not yet conclusive. Funding: None