Electroclinical characteristics and syndromic associations of "eye-condition" related visual sensitive epilepsies-A...

The systematic study of visual phenomena such as eye closure (ECLS), eye-closed/fixation-off sensitivity (FOS) [terminology proposed as eye-condition sensitive (ECS) epilepsy] distinct from photosensitivity is rarely explored in literature.

Clinical, electroencephalographic (EEG) and imaging records of patients attending an epilepsy clinic were screened. Inclusion criterion was demonstrable electrographic visual sensitivitiy in the form of ECS parameters with/without photosensitivity. Subsequently, detailed analysis of their data was undertaken.

Fifty two patients had one or more ECS parameters. Mean age of onset of epilepsy of the cohort was 10.26 ± 7.79 yrs. A family history of seizures was noted in 17% of the cohort. ECLS, FOS, combination of both, co-existent scotosensitivity and photosensitivity were noted in 32.6%, 48.1%, 19.2%, 23.1% and 30.8% respectively. Epilepsy syndromes included late-onset childhood occipital epilepsy-Gastaut variant (23.1%), reflex occipital lobe epilepsy with ECS without photosensitivity (21.2%), idiopathic photosensitive occipital epilepsy (13.5%), genetic generalized epilepsy (13.5%) and symptomatic epilepsy (28.7%) predominated by patients with posterior cortex gliosis or who were imaging negative. The idiopathic group also had lower seizure score and marked sleep activation of epileptiform abnormalities. Co-existent phostosensitivity was associated with a significantly higher predisposition for female gender, ECLS, generalized seizures and spikes with lower prevalence of FOS and extra-occipital spikes. Parieto-occipital spikes were noted in 88.4% patients.

Syndromic heterogeneity is evident in ECS epilepsies. These form a unique subset of visual-sensitive epilepsy syndromes with focal or generalized seizure subtypes of idiopathic or symptomatic etiologies, with and without associated photosensitivity.