Electrographic Features of Epilepsy With Eyelid Myoclonia With Photoparoxysmal Responses

Epilepsy with eyelid myoclonia (EMA) is characterized by eyelid myoclonia, eyelid closure sensitivity, and photosensitivity. EEG may manifest with frontal-predominant (FPEDs) or occipital-predominant epileptiform discharges (OPEDs). Data on clinical and electrographic features of these two subtypes are lacking. The purpose of our research was to look at baseline electroclinical features of EMA subtypes and to study electrographic findings of patients with EMA during intermittent photic stimulation (IPS).

We retrospectively identified all patients who had photoparoxysmal responses on EEGs performed at Cleveland clinic between January 01, 2012, and December 31, 2019. Patients who met diagnostic criteria for EMA were studied further.

Of the 249 patients with photoparoxysmal responses, 70 (28.1%) had EMA (62 [88.6%] female; the mean age of epilepsy onset: 7.0 ± 7.9 years). Patients with EMA had either FPEDs or OPEDs. Eleven patients with EMA (15.7%) had seizures (4 absence, 5 myoclonic and 2 bilateral tonic-clonic) during IPS. Patients with OPEDs were more likely to have drug-resistant epilepsy; occipital focal IEDs and other focal IEDs (other than frontal/occipital) on baseline EEG; and generalized IEDs with occipital predominance, generalized IEDs with no predominance, or focal IEDs during IPS. Predictors of seizure occurrence during photic stimulation included the presence of focal occipital IEDs on baseline EEG, generalized IEDs with frontal predominance during IPS, and photoparoxysmal response outlasting the stimulus.

Our study provides evidence that EMA has two distinct subtypes, which differ in clinical characteristics, baseline EEG, and EEG during photic stimulation. We highlight diagnostic and prognostic implications of these findings. Our study also details EEG characteristics of patients with EMA during IPS.