Epilepsy with eyelid myoclonia beyond the classical phenotype: Longitudinal electroclinical observations in a pediatric cohort.

OBJECTIVE: Epilepsy with eyelid myoclonia is a childhood-onset generalized epilepsy syndrome with variable recognition of eyelid myoclonia, eye-closure sensitivity, and photosensitivity during follow-up. We aimed to characterize longitudinal clinical and electroencephalographic features in pediatric epilepsy with eyelid myoclonia, focusing on delayed recognition, reflex electroencephalographic variability, electroclinical evolution, and treatment outcomes. METHODS: We retrospectively reviewed 27 children with epilepsy with eyelid myoclonia followed between April 2020 and March 2026. Clinical characteristics, seizure evolution, serial electroencephalographic findings, neuroimaging data, and antiseizure medication responses were analyzed. Longitudinal electroclinical trajectories were summarized descriptively and not considered predefined or validated disease subtypes. RESULTS: Among 27 patients, eyelid myoclonia was recognized at presentation in 14 and during follow-up in 13. Of 10 patients initially presenting with isolated eyelid myoclonia, additional seizure types emerged in six, whereas four retained an isolated phenotype throughout follow-up. The complete classical electroclinical phenotype was present at onset in only four patients. A photoparoxysmal response was documented in five patients, and focal epileptiform discharges in four patients. Epileptiform abnormalities persisted in 10 of 21 seizure-free patients. These findings demonstrate substantial heterogeneity in clinical evolution and electroencephalographic expression. Favorable seizure outcomes were observed in many lamotrigine-treated patients. SIGNIFICANCE: In childhood epilepsy with eyelid myoclonia, classical electroclinical features may be incomplete at onset, and eyelid myoclonia may initially be missed. Repeated clinical and electroencephalographic assessment is important when epilepsy with eyelid myoclonia is suspected, and absence of photosensitivity or classical reflex electroencephalographic features should not exclude the diagnosis when the clinical phenotype is suggestive. Persistent epileptiform abnormalities despite clinical seizure freedom should be interpreted within the broader clinical context. Although favorable outcomes were observed in many patients, the retrospective design precludes conclusions regarding comparative treatment efficacy.