Methodology of photic stimulation revisited: updated European algorithm for visual stimulation in the EEG laboratory

Dorothée Kasteleijn-Nolst Trenité, Guido Rubboli, Edouard Hirsch, Antonio Martins da Silva, Stefano Seri, Arnold Wilkins, Jaime Parra, Athanasios Covanis, Maurizio Elia, Giuseppe Capovilla, Ulrich Stephani, Graham Harding

Research output: Contribution to journalArticlepeer-review


Intermittent photic stimulation (IPS) is a common procedure performed in the electroencephalography (EEG) laboratory in children and adults to detect abnormal epileptogenic sensitivity to flickering light (i.e., photosensitivity). In practice, substantial variability in outcome is anecdotally found due to the many different methods used per laboratory and country. We believe that standardization of procedure, based on scientific and clinical data, should permit reproducible identification and quantification of photosensitivity. We hope that the use of our new algorithm will help in standardizing the IPS procedure, which in turn may more clearly identify and assist monitoring of patients with epilepsy and photosensitivity. Our algorithm goes far beyond that published in 1999 (Epilepsia, 1999a, 40, 75; Neurophysiol Clin, 1999b, 29, 318): it has substantially increased content, detailing technical and logistical aspects of IPS testing and the rationale for many of the steps in the IPS procedure. Furthermore, our latest algorithm incorporates the consensus of repeated scientific meetings of European experts in this field over a period of 6 years with feedback from general neurologists and epileptologists to improve its validity and utility. Accordingly, our European group has provided herein updated algorithms for two different levels of methodology: (1) requirements for defining photosensitivity in patients and in family members of known photosensitive patients and (2) requirements for tailored studies in patients with a clear history of visually induced seizures or complaints, and in those already known to be photosensitive.
Original languageEnglish
Pages (from-to)16-24
Number of pages9
Issue number1
Early online date16 Nov 2011
Publication statusPublished - Jan 2012


  • adult
  • algorithms
  • child
  • electroencephalography
  • reflex epilepsy
  • Europe
  • humans
  • photic stimulation
  • seizures
  • visual perception
  • guidelines
  • photoparoxysmal response
  • intermittent photic stimulation
  • standardization


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