Abstracts

Rationale: PGES is relatively common (27-40%) with generalized tonic clonic seizures (GTCs) observed on the epilepsy monitoring unit (EMU) and was significantly longer in patients that subsequently died of SUDEP than in those that survived. In addition, an increase in skin conductivity has been shown to be associated with duration of PGES. We sought to determine whether peri-ictal physiologic changes in the autonomic nervous system are correlated with PGES in order to identify additional potential risk factors for SUDEP. Methods: Six children with epilepsy, aged 3-18 and undergoing video EEG have been enrolled into the study with an enrollment target of 30 patients by November 2012. During monitoring, the patients wore unobtrusive commercially-available sensors that continuously recorded heart rate, respiration, and skin conductivity. The latter is missing on the first 2 patients enrolled. Results: Three GTCs among 15 total seizures were observed, 2 of which were followed by PGES (8 sec and 40 sec duration). Physiological changes during the pre-ictal, ictal and PGES periods are summarized in Table 1. All 3 seizures demonstrated marked changes in heart rate and depth of breath (respiration amplitude) during the ictal period when compared with a one-minute pre-ictal interval. Heart rate and respiration amplitude peaked during the ictal period, but remained elevated throughout PGES. Sweat gland activity, quantified by the skin conductivity sensor, was measured during one GTC event that was followed by 40 seconds of PGES. Skin conductivity began to increase toward the end of the ictal period, and surged throughout the PGES period. Conclusions: Autonomic dysfunction during the ictal and post-ictal periods may be associated with generalized seizures and is postulated to be a contributing factor to SUDEP which is a rare event. We demonstrated a robust sympathetic surge in heart rate and skin conductivity during PGES as compared to the ictal period. If this finding is replicated in our larger study of 30 patients, it may help explain the reported association between duration of PGES and SUDEP.