Rationale: The quantitative analysis of the photoparoxysmal response (PPR) to intermittent photic stimulation (IPS) becomes a promising method of the assessment of photosensitivity (PS). The pattern of PPR propagation underlies the model used for calculations. The generalization of a discharge should correspond with the parameters objectively characterizing the PPR in both cerebral hemispheres, and yet to date no evidence of a postulated symmetry has been revealed. Methods: We aimed to investigate the interhemispheric symmetry by comparing the EEG amplitude and interhemispheric coherence in both hemispheres in 100 non-epileptic individuals of both sexes, aged five to 18 years, with PS grade IV (sample) and without PS (control). Results: The distribution of amplitude values between the hemispheres was comparable in both groups, but significantly different between the sample and the control. Individual tracks of propagation revealed the hemispheric symmetry. ICoh values were significantly higher in occipital, temporal and fronto-polar areas in children with PS. Conclusions: PPR in children with PS shows a symmetry between cerebral hemispheres. An interhemispheric propagation is facilitated in children with PS and the propagation is more likely in the occipital and temporal regions. The study provides an objective evidence of the interhemispheric symmetry in pediatric PPR Funding: Please list any funding that was received in support of this abstract.: No funding
