Photoparoxysmal Response

An abnormal brain response to flashing lights or patterns, detected through electroencephalogram (EEG) monitoring during intermittent photic stimulation. A photoparoxysmal response indicates photosensitivity and potential risk for photosensitive epilepsy, though not everyone who exhibits PPR will experience seizures. PPR is graded on a scale from localized occipital spikes to generalized discharges. Research on PPR rates at different flash frequencies informs the thresholds used in accessibility guidelines like WCAG SC 2.3.1.