Abstracts

Rationale: Infantile spasms are the defining seizures of West syndrome, an early life epilepsy associated with refractory seizures, severe developmental consequences and early mortality. To better understand why some infants develop spasms, we compared infants with and without spasms with respect to age and clinically determined etiology.  Methods: 775 children were prospectively recruited at the time of initial diagnosis of epilepsy (onset < 3 years) from 17 US-based pediatric epilepsy programs.  Age, gender, gestational age (GA), and clinically assessed etiology were compared in children who presented with spasms (N=231), evolved to have spasms (N=41) and who never developed spasms over the course of a 1-yr follow-up (N=503).  Results: 408 (53%) children were boys. The average age of epilepsy onset was 11.1 mos (SD=9.4). Age of spasms onset had a striking peak near 6 months whereas other seizures were more concentrated at younger ages and decreased in frequency with age (Figure).  Onset of first seizure was An etiological factor was identified in 60% (155/253) of infants with spasms and 40% (109/256) without (p Conclusions: Spasms are a distinct seizure type with a quintessential neurodevelopmental component.  The broad etiological inputs, distinct peak of age at onset, and association with gestational age -- suggestive of a correction factor to allow preterm babies to reach a target age in brain development -- all point to a perfect storm of neurodevelopmental events and pathways with a common final manifestation.  Spasms are known to have substantial variation in seizure and developmental outcomes. Potentially, this reflects heterogeneity of the inputs resulting in spasms and suggests a need to focus on the mechanisms rather than the seizure type alone.   Funding: The Pediatric Epilepsy Research Foundation., Dallas, TX