Photoparoxysmal response
An abnormal EEG response to photic stimulation, indicating increased photosensitivity and seizure risk.
Full Definition
Photoparoxysmal response (PPR) is an abnormal electroencephalographic response characterized by epileptiform discharges triggered by intermittent photic stimulation during routine EEG testing. The response typically consists of spike-wave or polyspike-wave complexes that occur in a time-locked fashion to the flashing light stimulus. PPR is a biomarker of photosensitive epilepsy and is graded on a scale from 1 to 4 based on the extent and morphology of the abnormal discharge. Patients with PPR may be at risk for seizures triggered by flashing lights, video games, or other visual stimuli.
Usage
Usage note: Graded 1-4; distinct from normal photic driving response which follows stimulus frequency.
In Context
- "The EEG demonstrated a grade 3 photoparoxysmal response at 15 Hz stimulation." — EEG interpretation report
- "Patients with photoparoxysmal response require counseling about photosensitive seizure triggers." — Clinical consultation note