Abstracts

Rationale: Although the pathophysiologic mechanism of sudden unexpected death in epilepsy (SUDEP) is unknown, autonomic dysfunction is thought to be the most likely. It has been hypothesized that respiratory depression resulting in SUDEP may be secondary to postictal generalized electroencephalography (EEG) suppression (PGES). Although PGES has been studied in adults, its significance in children has not been fully assessed. We sought to determine whether PGES is associated with ictally mediated autonomic changes and increased risk of SUDEP in children. Methods: Children admitted to our Pediatric Epilepsy Monitoring Unit (PEMU) between 3/2009 and 10/2011 were prospectively recruited for our study. Clinical and electrophysiological data from children with PGES (an absence of electroencephalographic activity in all leads viewed at >= 10 microvolts amplitude immediately following seizure offset) on scalp EEG were compared to those without PGES. Data collected included the occurrence of peri-ictal tachycardia, bradycardia, and hypoxemia. SUDEP risk was assessed using SUDEP-7 Inventory scores (DeGiorgio CM et al., Epilepsy & Behavior 2010; 19(1): 78-81). Results: Thirty seven children with 168 seizures were analyzed. PGES was observed following 27/168 (16.1%) seizures in 12/37 (32.4%) children. Only primary and secondarily generalized tonic clonic (GTC) seizures were marked by PGES. PGES in children was significantly associated with peri-ictal tachycardia (p=0.019) and hypoxemia (p=0.005). For partial seizures with secondary generalization, PGES was more likely to be observed following temporal versus extratemporal onset seizures (p=0.012). Children with PGES also had significantly higher SUDEP-7 Inventory scores than those without PGES (4.2+/-1.3 versus 2.8+/-1.4, p=0.007). However, the scores were not significantly different between children with and children without peri-ictal tachycardia (3.4+/-1.3 versus 2.5+/-1.6, p=0.12), bradycardia (4+/-2 versus 2.9+/-1.4, p=0.45), or hypoxemia (3.4+/-1.5 versus 2.4+/-1.3, p=0.051). Conclusions: Children with PGES have more risk factors for SUDEP than children without PGES as measured by the SUDEP-7 Inventory. Therefore, PGES may prove to be a useful electrophysiological finding to assess SUDEP risk in children. Conversely, peri-ictal tachycardia, bradycardia, and hypoxemia are not associated with significantly higher SUDEP-7 Inventory scores.