Abstracts

Rationale: Signs indicating the end of a focal seizures characterized by loss of awareness and/or responsiveness are (LOA/R) are poorly defined and can be difficult to detect. Not recognizing changes between ictal and postictal behavior can affect accuracy of seizure reporting by family members and may lead to erroneous nursing response or seizure classification during video EEG review. Methods: Our epilepsy monitoring unit database was searched for focal seizures without secondary generalization for the period from 2007 to 2011. The first focal seizure in a patient with LOA/R and/or behavioral arrest and/or automatisms were included. Seizures without objective symptoms or inadequate video-EEG quality were excluded. Seizure onset was defined by the first clinical or EEG change indicating seizure onset. Seizure end was determined by resolution of the ictal EEG pattern. Results: A total of 41 patients were included, 10 men, 31 women, average age 43.1 (19-80), 30 with temporal, 11 with extra-temporal focal epilepsy; 23 from the left and 17 from the right hemisphere. Average clinical duration 1:18 min (0:14 - 10:36), electrographic duration 1:21 min (0:05 - 10:38). 21 events occurred out of wakefulness and 20 out of sleep (stage II or deeper). In the 21 awake patients, four went untested. 20 showed abrupt change in motor activity and contact with the environment. Specific signs were seen in 10 out of 21 events: nose wiping in 5, cough in 3, throat clearing or deep sigh in 2. Eleven of 20 events out of sleep went untested. Four out of the 11 patients went back to sleep without awareness of the event, one of them showed nose wiping. Seven of 11 were awake at the end of the seizure, a sigh or cough was seen in 3. None of them alerted the nursing staff about having had a seizure. Of the nine tested seizures out of sleep, 8 showed an abrupt change in behavioral activity and contact at the end of the event. Nose wiping was seen in 3, sigh and spontaneous laughter were seen each in 1 patient. Specific ending signs (nose wiping, cough, sigh or throat clearing, laughter) were seen in 19 out of 25 temporal lobe seizures and 8 out of 16 extra-temporal lobe seizures (Fisher exact, p=0.11). Conclusions: Seizure ending signs are often subtle and the most common finding is a sudden change in motor activity level and resumption of contact with the environment. More specific signs, nose wiping, coughing or throat clearing, or a deep sigh, are seen in around half of patients. There was a trend of those signs being more frequent in temporal vs. extra-temporal seizures, which would be consistent with an insular, autonomic mechanism. A significantly higher proportion of seizures out of sleep went untested as compared to those out of wakefulness (11 out of 20 compared to 4 out 21, p=0.025, OR 5.2, 95% CI: 1.1-27.3), despite 24 hour supervision. None of the 11 patients with untested seizures out of sleep were aware of their events afterwards. This demonstrates that seizure semiology can be very subtle and arousals during video monitoring should alert the monitoring staff.