Abstracts

Rationale: Epileptic seizures present with diurnal and nocturnal periodicity. Secondary generalization of seizures based on 24 hour periodicity, day/night or wake/sleep has not been investigated. Sleep and circadian periodicity may influence epileptogenicity in specific regions of the brain and potentially influence secondary generalization of seizures.Methods: 380 consecutive pediatric patients (0-21 years) with epilepsy and video-EEG (V-EEG) over 2 years were reviewed for seizure semiology with secondary generalization, EEG localization, occurrence during the day (6AM-PM) or night, during wakefulness/ sleep, 3-hour time blocks, epilepsy localization and etiology. Seizures were analyzed based on ILAE seizure terminology. Patients with recorded EEG seizures were included. Statistical analysis was performed using binomial testing.Results: Out of 380 patients, 225 met the inclusion criteria of recorded epileptic seizures. In these 225 patients a total of 1,008 epileptic seizures were recorded. The mean age of the patients (113 boys and 112 girls) was 8.5 years +/- 5.7 years. 127 out of 225 patients (527 seizures) presented with evolution of semiological seizure type into a second or third semiological seizure phase, including 27 patients (86 seizures) with evolution into generalized tonic clonic (GTC) seizures. 527/1008 seizures had a second seizure phase, and 162/1008 seizures evolved into a third phase. Combining the second and third evolution phase of seizures, the following evolution patterns were seen: 86 GTC (12.5%), 1 aura (0.15%), 255 clonic (37%), 83 tonic (12%), 93 automotor (13.5%), 40 hypermotor (5.6%), 19 dyscognitive (2.8%), 4 hypomotor (.58%), 37 myoclonic (5.4%), 54 versive (7.8%), and 17 epileptic spasms (2.5%). Sleep was more frequently related to secondary generalization than wakefulness (p<0.001). Secondary generalization of seizures during day or nighttime did not differ. Secondary generalization of seizures was most frequently seen between 3AM and 9AM (p<0.01) irrespective of sleep. Secondary generalization during sleep occurred most frequently between 12AM-9AM (p<0.001). Seizures which evolved into a second or third phase consisting of generalized, parietal, or frontal EEG patterns occurred most frequently out of sleep (p<0.001). Generalized seizures (p<0.01) and multiregional EEG seizures (p<0.001) related to evolution were most frequently seen between 6-9AM . Patients with MRI findings exhibiting lesions were more likely to have secondary generalization seizures during sleep (p<0.001). MRI lesions were not related to circadian seizure patterns of seizure evolution.Conclusions: Evolution into secondary generalization during pediatric seizures occurred most frequently out of sleep, with peaks between 12AM and 9AM. Secondary generalization was more frequently seen in patients with abnormal MRIs. Our data may assist in identifying times and epilepsy types in pediatric epilepsy patients at greatest risk for secondary generalization.