photoparoxysmal response
Pronunciation: foh-toh-par-ok-SIZ-mal
An abnormal EEG reaction to flashing light stimulation, characterized by epileptiform discharges.
Full Definition
A photoparoxysmal response (PPR) is an abnormal electroencephalographic reaction to intermittent photic stimulation, characterized by the appearance of epileptiform discharges such as spikes, sharp waves, or spike-wave complexes. This response indicates photosensitivity and is typically seen in patients with photosensitive epilepsy syndromes, particularly juvenile myoclonic epilepsy and generalized tonic-clonic seizures. The PPR is graded on a scale from 1 to 4 based on the extent and morphology of the abnormal activity. Detection of a photoparoxysmal response has important implications for seizure management, as patients must avoid flashing lights and other photosensitive triggers.
Usage
Usage note: Often abbreviated as PPR; graded on a numerical scale in clinical reports.
In Context
- "A grade 3 photoparoxysmal response was elicited during photic stimulation at 18 Hz." — EEG photosensitivity assessment
- "The absence of photoparoxysmal response ruled out photosensitive epilepsy as a trigger for her seizures." — Epilepsy evaluation report