Department of Neurology

Strobe lights and seizures

Q: Please reference the effects of strobe lights on seizures.

The long-term care facility that I'm involved with ( as a physical therapist and a seizure patient) has recently installed strobes as part of their fire safety system. I would like to have some information to give to the maintainance department regarding the possible effects on people with seizure disorders.

Any help would be appreciated.

A: A small minority of persons with epilepsy have photosensitivity, which means that flashing or flickering lights may trigger a seizure, which is usually a tonic-clonic (convulsive) seizure. On EEG, this response is seen especially at frequencies of 10-20 flashes per second. If you have had an EEG, you might have noticed that they will use a strobe during the recording to see if you have photosensitivity. The most common sources of flashing light that would trigger a seizure include televisions (hence, the association with video-games). We have also seen instances of seizures triggered by flashing light from by waving of hands in front of the face, sun passing through a picket fence while riding in a car, reflections off a running stream of water, flames from a fire, and of course, disco strobes. In most cases, this type of seizure is very sensitive to valproate (Depakene, Depakote).

Usually the fire alarm strobes flash at a slow rate, for example about 1 flash per second. They are intended to alert persons who may be deaf or hard of hearing. At a very slow frequency, the light is probably not that seizure provoking. However, you may wish to contact your maintenence department about this.

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