Photosensitivity and Reflex Epilepsies

Abstract

Reflex epilepsies (RE) objectively and consistently provoked by specific external or internal stimuli are important clues for investigating complex mechanisms of epileptogenesis. RE have many intriguing subtypes depending on the trigger. Visually-sensitive epilepsies or photosensitive epilepsies are genetically determined and constitute the major part of RE but their diversity is even huge both clinically and electrophysiologically. Reflex seizures can occur in both focal and generalized epilepsy syndromes and can also be associated with spontaneous seizures. Afferent external stimuli can be: elementary or elaborate, structured and complex. Moreover, triggering activity may also be elementary (motor movement) or elaborate (reading, chess playing), or both (reading aloud). Complex forms of RE pose many different questions and there are reported cases with various symptomatic etiologies indicating some acquired factors besides genetics. This review will focus on the current understanding of RE and its pathogenetic implications.