Human photosensitivity: from pathophysiology to treatment


Alberto Verrotti, Department of Medicine, Section of Pediatrics, University of Chieti – Ospedale Policlinico, Via dei Vestini 5, 66100 Chieti, Italy (tel.: + 39 871 358015-574538; fax: +39 871 574831; e-mail:


Photosensitivity is a condition detected on the electroencephalography (EEG) as a paroxysmal reaction to Intermittent Photic Stimulation (IPS). This EEG response, elicited by IPS or by other visual stimuli of daily life, is called Photo Paroxysmal Response (PPR). PPRs are well documented in epileptic and non-epileptic subjects. Photosensitivity rarely in normal individuals evolves into epilepsy. Photosensitive epilepsy is a rare refex epilepsy characterized by seizures in photosensitive individuals.

The development of modern technology has increased the exposition to potential seizure precipitants in people of all ages, but especially in children and adolescents. Actually, videogames, computers and televisions are the most common triggers in daily life of susceptible persons.

The mechanisms of generation of PPR are poorly understood, but genetic factors play an important rule.

The control of visually induced seizures has, generally a good prognosis. In patients known to be visually sensitive, avoidance of obvious source and stimulus modifications are very important and useful to seizure prevention, but in the large majority of patients with epilepsy and photosensitivity antiepileptic drugs are needed.