Disenfranchisement of reflex seizures ending?Posted: 04/16/2014
A new definition of epilepsy published this week affirms that photosensitive and other reflex seizures qualify as “real” epilepsy. This clarification may eventually help increase awareness of seizures from video games and other electronic media.
Although reflex seizures have long been included in official classification schemes of epileptic seizures, they don’t fit cleanly into established categories of seizure types and epilepsy syndromes. In neurology training they are typically mentioned only briefly. And typically they are taken too lightly by doctors using the prevailing diagnostic criteria for epilepsy: at least two unprovoked seizures at least 24 hours apart.
Because reflex seizures, by definition, are provoked by specific triggers, there’s confusion and most doctors have been reluctant to diagnose epilepsy in people whose epileptic seizures require an environmental provocation. The authors of the new definition paper acknowledge this:
“Under limits of the current definition, [a] patient might have photosensitive epilepsy, yet not be considered to have epilepsy because the seizures are provoked by lights…People with reflex epilepsies previously have been disenfranchised by the requirement that seizures be unprovoked. The inclusion of reflex epilepsy syndromes in a practical clinical definition of epilepsy now brings these individuals into the epilepsy community.”
Diagnostic criteria under the new definition now include at least two unprovoked or reflex seizures at least 24 hours apart. The new definition also allows an epilepsy diagnosis after a single seizure–either unprovoked or reflex–if there is a high probability of recurrence.
I’ve written previously about the inconsistency inherent in using the criterion of “unprovoked” to diagnose epilepsy in people whose seizures happen only in response to sensory triggers such as flashing light. This thinking (along with the assumption that photosensitive epilepsy is very rare) has led to marginalization of reflex seizures in the research community and among clinicians as well. Marginalization means doctors have been underdiagnosing reflex epilepsy, researchers seeking funding pursue other topics to study, and the public and public policy makers are largely unaware of the public health issue of photosensitive seizures.
The practical clinical definition was developed by a 19-member multinational task force of the International League Against Epilepsy (ILAE), incorporating input from hundreds of other clinicians, researchers, patients, and other interested parties. I’m more than pleased that the ILAE is choosing to make it clear that reflex epilepsy deserves the same respect as other forms of the disease (the new definition paper characterizes epilepsy as a disease rather than a disorder). It’s fortunate that the chair of the ILAE task force that produced the new definition is Robert Fisher, MD, PhD of Stanford, lead author of the 2005 consensus paper describing seizures from visual stimulation as “a serious public health problem.” No doubt Dr. Fisher’s appreciation of the magnitude of the problem was instrumental in ensuring that the task force addressed it.
Not all epileptologists agree with all aspects of the new epilepsy definition–and Epilepsia has given them a voice as well, publishing half a dozen commentaries, all of which are available free online. I contributed a piece as well, providing a patient/family perspective.
Of course, it remains to be seen how long it will take for neurologists to shift their attitudes and diagnostic practices regarding reflex epilepsy. Perhaps the inclusion of reflex seizures in the epilepsy definition will help dispell the idea that reflex seizures are rare.