Etiology and Long-Term Outcomes of Late-Onset Infantile Spasms

Objectives The purpose of the study was to evaluate the etiology and long-term outcomes of late-onset epileptic spasms (LOS). Methods This is a retrospective analysis of all consecutive patients seen at our center with onset of clusters of epileptic spasms between 1 and 3 years of age in 1995 through 2005. Results Overall, 17 children with LOS were identified. Overall, 14 children (82%) had structural etiology. Six patients received resective surgical treatment. Five had focal cortical dysplasia type 1 (FCD1) histology (29% of all the patients). Overall, 16 children were followed for 2 to 18 years. At the latest follow-up, seizure freedom was observed in 67% of the operated and in 50% of the nonoperated patients. Normal cognition or only mild mental deficiency was observed in nine patients (56%), of whom eight were seizure-free. All patients with intractable spasms had a severe mental deficiency. Conclusion The overall cognitive outcome of LOS was more favorable than in the previous reports and was associated with seizure freedom. FCD1 is a frequent etiology for LOS and the cognitive outcome of patients with FCD1 seemed to be favorable.