Low-luminance visual stimuli compared with stroboscopic IFS in eliciting PPR in photosensitive patients

Purpose: Photosensitivity is thought to play the most important role in the genesis of electronic screen games induced seizures (ESGIS). To elicit pho toparoxysmal response (PPR) effectively, we performed EEG activation by low -luminance visual stimuli: 20 cd/m(2) deep-red flicker and flickering 2 c/d eg geometric pattern stimuli produced by strobofilters. We investigated eff icacy of eliciting PPR by use of Grass PS33-plus stroboscopic 18-Hz intermi ttent photic stimulation (IPS) and low-luminance 18-Hz visual stimuli. Methods: We studied 31 photosensitive patients. We gave stroboscopic IFS (e yes closed and eyes open); after deep-red flicker stimulation (eyes open), we gave flickering geometric-pattern stimuli by using dot, vertical grating , and horizontal grating patterns. Results: Stroboscopic IFS elicited PPR in 14 patients, whereas absence of P PR provocation was found in 17 patients. Low-luminance visual stimuli elici ted PPR in 30 patients, whereas absence of PPR provocation was found in onl y one patient. These PPR provocation differences in both stimuli were stati stically significant (p < 0.001). Conclusions: The data suggest that low-luminance visual stimuli as describe d are useful for EEG diagnosis of ESGIS when seizures are thought to be due to photosensitivity.