Photosensitive epilepsy = Purple Day epilepsy?Posted: 03/25/2012
In 2008 an international epilepsy awareness campaign was started that designates March 26 as Purple Day. It’s a grassroots movement that provides a framework for organizing fund-raising and educational events…should people with photosensitive epilepsy be part of it? Where do visually induced seizures fit in the epilepsy world?
Somehow, photosensitive epilepsy and other reflex epilepsies, where seizures occur in response to a specific stimulus, tend not to get much notice. This is true among clinicians and the community of people with “regular” epilepsy. I can think of several factors contributing to the marginalization of photosensitive epilepsy:
1) It starts with ambivalence among the research and clinical communities as to whether photosensitive epilepsy qualifies as “real” epilepsy. The belief that this is a rare condition has a way of relegating photosensitive epilepsy to the sidelines of epilepsy research funding, advocacy, and clinical concerns. In a future post I’ll need to further explore the issues of why the estimates of its 1 in 4,000 prevalence are tough to swallow.
“…reflex epilepsy is regarded by some as a clinical curiosity and an interest such as butterfly collecting, an attractive thing of no great consequence. We are convinced that this idea is wrong…”
— Benjamin G. Zifkin, MD, co-editor of Reflex Epilepsies and Reflex Seizures (Advances in Neurology, vol. 75), from his preface to this collection of articles for neurologists. Sounds good.
But then Zifkin continues, “Although reflex epilepsy is not common, properly studied it teaches us about the brain in general and about epilepsy in particular.” (OK, it’s not a curiosity, it’s a tool for studying the real epilepsy.) Based on his extensive writings on the subject, I suspect Dr. Zifkin is extremely aware of the intrinsic seriousness of photosensitivity — but in the preface to his scholarly book he was appealing to the wider audience of neuroscientists who continue to view it as a trifle.
2) Another problem that creates confusion and perpetuates the ambivalence is the manner in which seizures are officially classified.
Here are two quotes from the NYU Langone Medical Center website that illustrate the essence of the confusion.
- Epilepsy is a disorder in which a person has two or more unprovoked seizures.
- In reflex epilepsies, seizures are triggered or evoked by specific stimuli in the environment.
How to reconcile these? What’s the difference between provoking and triggering/evoking?
When epilepsy experts describe seizures as “unprovoked,” they are referring to seizures that are not brought on by a temporary medical situation. Unprovoked seizures are an expression of a chronic, underlying neurological condition, often not identifiable, such as a lesion or a subtle malformation in brain tissue.
“In general, seizures do not indicate epilepsy if they only occur as a result of a temporary medical condition such as a high fever, low blood sugar, alcohol or drug withdrawal, or immediately following a brain concussion. Among people who experience a seizure under such circumstances, without a history of seizures at other times, there is usually no need for ongoing treatment for epilepsy, only a need to treat the underlying medical condition.”
If the structure and biochemical environment of the brain are such that exposure to visual stimuli such as lights and patterns brings on a seizure, this is likely a permanent condition (only 25 percent of patients outgrow photosensitivity). Therefore this kind of sensitivity should be considered a form of epilepsy. A brain tumor that causes seizures, however, is not considered to be causing epilepsy.
3) There’s enormous reluctance for clinicians to diagnose epilepsy, driven in part by backlash against more liberal diagnosing practices in the past, which may have unnecessarily exposed some patients to anti-epileptic drugs. Clinicians are typically quite strict about needing conclusive EEG evidence to assign the diagnosis.
4) Epilepsy is still a frightening word. Most clinicians avoid it, preferring to talk about seizures. So if your seizures are triggered exclusively by a video game or strobe light, why call your sensitivity to visual stimuli by such a scary name?
5) The advocacy community remains focused on severe, life-threatening forms of epilepsy. Obtaining funding to find cures for these devastating disorders is their top priority.
So where does that leave you on March 26? Are you part of the epilepsy community or not?