Characteristics of Patients With Epileptic Spasm Onset Over 2 Years of Age.

BACKGROUND

The definition of late-onset epileptic spasms has shifted from epileptic spasm (ES) onset over one-2 years of age, due to the emergence of infantile epileptic spasms syndrome. This study investigated differences in clinical characteristics between patients who demonstrated ES at one-2 years of age versus >2 years of age.

METHODS

This retrospective study included patients aged ≥one year who developed ES and visited Saitama Children's Medical Center between January 1, 1990, and March 31, 2023. Patients were classified based on age at ES onset into the one-2-year-old group (one-2 years group) and the older-than-2-year-old group (≥2 years group). The clinical characteristics of each group and the differences in clinical characteristics between the two groups were investigated.

RESULTS

The one-2 years group included 10 patients, while the ≥2 years group comprised 8 patients. Comparison between the two groups revealed that the ≥2-year group exhibited higher developmental quotient at ES onset, longer lead time, and more misdiagnosis, and less hypsarrhythmia on interictal electroencephalography. At the last follow-up, intellectual disability (ID) was present in all patients across both cohorts. Regarding the severity distribution of ID, higher proportion of patients in the ≥2 years group demonstrated mild ID and a lower proportion demonstrated severe ID compared to those in the one-2 years group.

CONCLUSIONS

Age at ES onset may reflect different clinical phenotypes and outcomes within the late-onset spectrum.