Abstracts

Rationale: Photic induced seizure (PIS) refers to seizures provoked by visual stimulations. Photoparoxysmal response (PPR) is an abnormal EEG response to light or pattern consisting of epileptiform discharges. While patients having PPR on EEG are said to be photosensitive, there is limited data available regarding correlation between PPR and PIS.The rationale for this study was to assess whether a patient with PIS could be identified by routine EEG using photic stimulation. With the increasing popularity of video games and parental concern of their predisposition for seizures, there is a need to identify individuals at risk for PIS. 1. To study the EEG response to photic stimulation in patients with PIS. 2. To study the clinical significance of PPR on EEG and determine the importance of PPR as an isolated predictor for PIS. Methods: This was a retrospective analysis of the Kaleida Buffalo EEG database containing EEGs from 1999 to 2013. We identified the EEGs of patients who came in with PIS. Their EEG response to photic stimulation and the triggers of PIS were studied. We also isolated EEGs with PPR and compared them with an age and sex-matched control group without PPR on EEG with regards to the incidence of PIS and associated EEG findings. For statistical analysis, two-tailed Fischer exact Chi Square test was used for the categorical variables. Significance level was kept at p<0.05. Results: There were 129 patients with PIS identified from 1999 to 2013. The incidence of PPR on their EEGs was only 6.2%. The main triggers for PIS were TV (37.2%) followed by computer (39.5%) and video games (23.2%). We isolated 86 EEGs done in the last 5 years that had PPR (PPR group) and a control group of 94 patients that did not show PPR on photic stimulations. Although there was a trend of higher incidence of PIS in the PPR group (13 out of 86) comparing to the control group (7 out of 94), it was not statistically significant (p=0.153). Conclusions: The study did not find a clear association of PPR and PIS. We concluded that PPR cannot be used as an isolated predictor for PIS.