What affects your odds of visual sensitivity?Posted: 09/12/2011
Do video game seizures worry you in particular? Should they?
Nobody knows the percentage of people whose sensitivity to flash and patterns could cause seizures. To find out with any statistical accuracy, researchers would need to do EEG testing with photic stimulation and patterns on large numbers of people. A population screening would be difficult due to sheer logistics and cost – attaching and removing EEG electrodes is a labor-intensive process as is properly performing the test. Pattern testing is rarely offered in the US In addition there are ethical considerations, since the photic stimulation could provoke a seizure.
Studies have found that 3 to 5 percent of epilepsy patients test positive for photosensitivity (whether or not they experience visually induced seizures). As I’ve noted previously, it’s really not known what percentage of the population without epilepsy (spontaneous seizures) is at risk for experiencing seizures induced by visual stimuli.
So, what known biological factors place you at higher risk for photosensitivity? These are things you can’t, in general, do much about:
- Being female
- Age 7 – 25
- Parent or sibling with photosensitivity
- Parent or sibling with febrile seizures
- A specific form of epilepsy, juvenile myoclonic epilepsy
- History of concussion
- History of frequent headaches
- Need for corrective eyeglasses
- In those with epilepsy, a history of myoclonic, tonic-clonic, or absence seizures
- Learning, behavioral, or psychiatric difficulties
These factors were ascertained in studies primarily by Graham Harding and Peter Jeavons in the UK and Dorothée Kasteleijn-Nolst Trenité in the Netherlands, leading researchers in photosensitivity and visually-induced seizures.
Note that studies measure the presence of a well-defined “photoparoxysmal” EEG pattern during exposure to photic stimulation (and sometimes, striped patterns). Its presence is a laboratory finding that does not invariably mean the test subject will experience seizures when exposed to flashing light and other visual provocation in everyday life.
Sensitivity in the same individual is affected by additional variables over which you have some control, such as fatigue, alcohol, distance away from the screen, etc.