Neuropharmacology & Neurotherapeutics
Oct. 07, 2021
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Differentiation of eye-closure (as seen in photosensitivity) from eyes-closed abnormalities (as seen in fixation-off sensitivity). (A) Eye-closure-related abnormalities in a patient with Jeavons syndrome (eyelid myoclonia with absences). High-amplitude, generalized discharges occur within 1 to 3 seconds of closing the eyes in a lit room. These are of brief duration, do not continue in the resting period that the eyes are closed, and are totally inhibited in complete darkness. (B) Eyes closed-related abnormalities in a woman who probably has cryptogenic epilepsy with seizures related to fixation-off sensitivity. The EEG paroxysms last as long as the eyes are closed. They are abruptly inhibited when the eyes are opened. The response to fixation-off and fixation-on were similar, irrespective of the means by which they were elicited (eyes closed, darkness, +10 spherical lenses, Ganzfeld stimulation). The best practical means for testing fixation-off sensitivity is with underwater goggles covered with opaque tape. (Used with permission from: Panayiotopoulos CP. Reflex seizures and related epileptic syndromes: a clinical guide to epileptic syndromes and their treatment. Revised 2nd ed. London: Springer, 2010:497-531.)