Abstracts

Rationale: There is ongoing debate whether Eyelid Myoclonia with Absences (EMA) can be recognized by the ILAE as a distinct epilepsy syndrome. The three criteria for EMA appear robust: (1) eyelid myoclonia with or without absences, with generalized discharges on EEG, triggered by eye-closure, (2) generalized photoparoxysmal response and (3) onset in childhood. However, eyelid myoclonia with epileptiform discharges upon eye closure is not a uniform phenonomenon, and not always indicative of photosensitivity. A fixation-off phenomenon (FOP) is activation of generalized discharges not triggered by the high contrast change of eye closure, but by loss of fixation during the eyes-closed state. FOP is elicited in the dark even with eyes open, and eye closure related discharges cannot be elicited by closing eyes in a dark room. Furthermore, light sensitivity can change as activation of the occipital cortex is dependent on light intensity (strobe versus sunlight, polarized lenses), volume of cortex activated (monocular stimulation) and cortical excitability (age and anti-epileptic medication). Methods: We report three children followed at Children's Hospital Boston for the clinical care of idiopathic generalized epilepsy with prominent eye-lid fluttering and light sensitivity. Their characteristics span the whole spectrum from fixation off, to eye-closure related discharges, to photosensitivity from either strobe or sunlight. Results: Patients range from age 7 to 14 at presentation. All had eyelid myoclonia, two with absences. All had EEGs with generalized (poly-)spike and wave complexes of 3-6 Hz, and normal exam, intelligence and imaging studies. All were refractory to first line antiepileptic drugs (AEDs). One patient also had myoclonus of the mouth, head and hands, and had a prominent FOP but no photosensitivity. Another patient was photosensitive but only to sunlight, and had discharges upon eye closure but no FOP. A third had eyelid myoclonia without absences provoked by sunlight, and had a prominent photoparoxysmal response with strobe but without clinical signs. See table for details. Conclusions: Eye-lid myoclonia with or without absences, eye closure sensitivity and photosensitivity are common features shared by several epileptic conditions. Complicating matters further, light sensitivity is dependent on light intensity, cortical activation and excitability. Epileptiform discharges upon eye-closure can be FOP, which has characteristics quite opposite to those of eye closure related dischares seen in photosensitivity. Our patients have an apparant similar presentation with eyelid myoclonia, a generalized EEG with photosensitivity and activation with eye closure. But there is more than meets the eye; only detailed clinical assessment and rigorous EEG analysis with application of multiple provocation techniques allow differentiation of EMA from similar conditions.