Reflex Epilepsy

Those with reflex epilepsy experience seizures that are triggered by an environmental stimulus. Reflex seizures occur as a reaction, or "reflex," to the stimulus. According to researchers at Toronto's Hospital for Sick Children, approximately 6 percent of people with epilepsy suffer from reflex seizures. Photosensitive epilepsy (seizures triggered by light) is the most common type of reflex epilepsy.

What Causes Reflex Epilepsy?

Reflex epilepsy is also known as "environmental epilepsy." This is somewhat deceiving, however, as the environmental triggers of epilepsy seizures are not the real causes of the seizures. More accurately, when the external stimulus is processed in the brain, it's processed in a seizure-sensitive area, and causes a seizure to develop.

Reflex epilepsy may be associated with:

• Genetic inheritance (photosensitive epilepsy is partly inherited)
• Minor structural abnormalities in the brain
• Other epilepsy syndromes (idiopathic epilepsy syndromes have been known to cause photosensitive epilepsy seizures).

Photosensitivity epilepsy (PSE) is by far the most common type of reflex epilepsy. It usually develops during childhood, whereas other reflex epilepsies can develop at any age. PSE seizures can develop as a result of:

• Alternating light and dark patterns
• Computer monitors
• Flashing or flickering lights
• Sunlight flashing through the trees while driving
• Television (most common stimulus for photosensitive seizures)
• Video games.

Other, less-common types of reflex epilepsy may be triggered by:

• Being startled
• Certain body movements
• Eating
• Hot water immersion
• Looking at patterns
• Music
• Reading
• Specific sounds or a certain tone of voice
• Thinking about certain topics
• Typing
• Writing.

People with reflex epilepsy typically do not exhibit any developmental or neurological problems.

What Does Reflex Epilepsy Look Like?

The vast majority of reflex epilepsy seizures are generalized tonic-clonic seizures. During a generalized tonic-clonic seizure, the individual will lose consciousness. His body will stiffen and his muscles will jerk involuntarily.

Although it's less common, reflex epilepsy may also produce absence seizures (staring) or myoclonic seizures (muscle contractions).

What's the Prognosis for Reflex Epilepsy?

The best treatment plan is to avoid the environmental triggers of epilepsy seizures. This is not always practical, however, and most people have to take a low dose of medication to help control their seizures.

Many people who develop photosensitive epilepsy as children eventually grow out of the disorder in their twenties. This is more likely in individuals whose seizures are well under control as children.

Resources

Donner, E. J et al. (2006). Reflex epilepsy. Retrieved March 25, 2010, from http://www.aboutkidshealth.ca/Epilepsy/Reflex-Epilepsy.aspx?articleID=6989