Eye closure sensitivity and related EEG findings: Persistence rates and classification of epilepsy syndromes by the International League Against Epilepsy.

BACKGROUND

We aimed to investigate the frequency and persistence rates of eye closure-related epileptiform EEG findings in a cohort with epilepsy and classify them according to the latest epilepsy syndrome classification by the International League Against Epilepsy (ILAE).

METHOD: Consecutive patients referred to the EEG laboratory, showing eye closure sensitivity (ECS) and related EEG findings, were included between October 2022 and August 2024. Their epilepsy syndromes were classified according to ILAE. EEG patterns were categorized as ECS, eye-closed sensitivity, and fixation-off sensitivity (FOS). Persistence rates were calculated for each patient by examining all eye closures in the EEG records. The clinical findings and persistence rates were compared between subgroups by SPSSv26.

RESULTS

Of 5084 EEG traces, 63 (1.3%) from 35 patients with ECS and related EEG findings were included, with a mean age of 21.28 ± 8.38 years, and 68.6% of them were female. ECS was present in 85.7% of the patients, while 14.3% had eye-closed sensitivity, of which 11.1% had FOS. In the cohort, 25.7% had focal epilepsy, whereas 74.3% had generalized epilepsy. The most frequent generalized epilepsy syndrome was epilepsy with eyelid myoclonia (EEM) in 25.7%. Genetic etiology was disclosed in one patient with propionic acidemia, and another had chromosomal duplication at 8p11.21q11.1. ECS was exacerbated by hyperventilation, awakening, and intermittent photic stimulation. Photoparoxysmal response (PPR) was more frequently associated with ECS than with eye-closed sensitivity (95% vs. 5%, respectively). Although the persistence rates (mean: 47.7% ± 8.3%) did not significantly differ with respect to clinical outcomes (18% vs. 21%, p = .33), age was negatively correlated with this ratio (r = -.521, p = .002).

SIGNIFICANCE: Eye closure sensitivity and related sensitivities in EEG exhibit heterogeneity across epileptic syndromes and prognosis. Investigating ECS within the framework of the latest epilepsy syndrome classification, alongside co-occurrences of other activation methods, and calculating persistence rates may offer valuable insights for future genetic research and long-term management.