Blockage of eye-closure-generated generalized paroxysms by mental activity

Abstract

Seizures and electroencephalography (EEG) paroxysms induced by eye closure. Are rare but a recognized form of stimulus induced epilepsy. We report a case of a 15-year-old male diagnosed with juvenile absence epilepsy in whom EEG paroxysms in the form of generalized three per second spike and wave bursts generated by sustained eye closure were consistently blocked during mental activity in the form of skip counting. To the best of our knowledge, this phenomenon has not been previously reported. We propose two possible mechanisms to account for this blockage, both based on reduction of excitability: (1) blockage of the seizures in the brainstem at the level of the reticular activating system, by raising the level of attention, via the thalamo-cortical circuitry, (2) task-specific, based on the model mechanism of “winner-takes-all“ which generates enhanced inhibition to produce cognitive selectivity.