Photosensitive Epilepsy may be a familiar term to people acquainted with playing video games. A mandatory warning appears in the beginning of video or computer games and even a few animated programs such as cartoons for kids, which have flashing graphics or flickering lights. Dr. Prithika Chary, a neurologist and neurosurgeon practicing at Kauvery Hospital, Chennai, Tamil Nadu speaks to Medindia about Photosensitive Epilepsy.
- Flickering Sunlight
- Moving Vehicle
- Sunlight Flickering Through Leaves
- Dr. Prithika Chary Neurologist Neurosurgeon
- Flashing Light
- Eye Patch
Q. What triggers photosensitive epilepsy?
AdvertisementA. Photosensitive Epilepsy is caused by natural lights such as sun flickering through the leaves or when a person is moving while in a vehicle watching irregular patterns of light. Artificial lights also cause photosensitive epilepsy when a person looks down from escalators, exposed to disco lights, or sees certain patterns such as stripes or checks.
Q. How does photosensitive epilepsy differ from other seizures?
A. There are many kinds of seizures. Grand mal seizure, generalized tonic clonic seizure affecting the brain, and absence seizures where a person is momentarily absent. It is often associated with eye blinks and staring. A person could get several attacks of absence seizures. Another kind is the focal seizure where the arm or face twitches, involuntary repetitive movements (automatism) and chewing or champing movements are observed. Then there is complex partial seizure where a person's awareness or the ability to respond fails.
Photosensitive Epilepsy is a generalized tonic clonic seizure.
Q. People of all ages watch TV or play video games so how is it only a few people have photosensitive epilepsy?
A. Three out of hundred people with epilepsy have photosensitive epilepsy. It depends on where the problem is, which is usually in the occipital lobe (the part of the brain responsible for vision). All people with epilepsy exposed to prolonged hours of viewing computer or television sometimes without even moving their eyes face the chances of developing photosensitive epilepsy.
Q. What is the diagnosis of photosensitive epilepsy?
A. Even routine electroencephalogram (EEG) may not detect photosensitive epilepsy. It is provoked during the EEG sessions where hyperventilation is induced in a person with epilepsy. Certain fits come about during these sessions even in the EEG rooms. In addition to EEGs, Photic stimulation aids in diagnosis, meaning a person with epilepsy is exposed to a certain number of flashes beginning from 5 flashes, then 10 flashes up to 40 flashes. If the person does have photosensitive epilepsy, the seizures will confirm the diagnosis.
Q. How can people affected by photosensitive epilepsy stay protected?
A. Young people below the age of 20 run a risk if they visit discos or dance clubs because of the flickering lights. People with photosensitive epilepsy should avoid viewing red flashing graphics. If the flashes per second (refresh rate) on the screen is anywhere between 15 to 20 hertz, it could trigger photosensitive epilepsy. So when the refresh rate (flashes per second) of a screen is low it causes seizures in people with photosensitive epilepsy. But these days, advanced model of screens have a refresh rate of 100 hertz, which does not pose a threat to people with photosensitive epilepsy. But an outdated screen, which has a low refresh rate of 50 hertz or below, may cause seizures in a person with photosensitive epilepsy.
Q. What are some of the precautionary measures for a person with photosensitive epilepsy?
A. A person with photosensitive epilepsy must avoid looking at the reflection of sunlight on water no matter how alluring it is. As a first aid measure, when there is a chance of seizure, the hand should immediately cover one eye or the person can wear an eye patch. This act reduces the number of neurons being stimulated, thus reducing the risk.
Q. When is it an emergency for a person to seek medical assistance? Who should one contact in case of an emergency?
A. A person with epilepsy can get seizures anytime. But it does not mean they are always vulnerable to having seizures. Sometimes the condition of epilepsy is complacent and a person may not have any seizure. The specialist one should visit to get medical attention is a neurologist.
Medindia thanks Dr. Prithika Chary for sharing information on Photosensitive Epilepsy.