Seizures occur when brain cells malfunction, discharging signals excessively in a disorganized, uncontrolled manner. The resulting surge of electrical energy that pulsates through the brain causes a variety of symptoms, ranging from clouded awareness to loss of consciousness. Vulnerability to seizures is referred to as epilepsy. For certain epileptic children, seizures can be triggered by viewing television. A variety of media--broadcast or cable television, DVDs, 3-D television and video games--played and viewed on a television monitor can all induce seizures in susceptible children.
Photosensitive Seizure
The Epilepsy Foundation reports that over 3 million Americans suffer from epilepsy. Only about 3 percent of these, however, have photosensitive seizures, or seizures that are triggered by flashing lights or by particular visual patterns. Photosensitive epilepsy occurs more often in epileptic children and adolescents, and especially in those with juvenile myoclonic epilepsy. It becomes less frequent as children age, and very few cases persist past the mid-twenties.
Symptoms
Usually seizures only last one or two minutes, though certain symptoms such as confusion, fatigue and headaches can persist well beyond the actual seizure. Many children aren't aware when they have a seizure. Often, only particular parts of the brain are affected, so children display different symptoms that vary in severity. Some may have a clouded sense of awareness and limits in their ability to communicate; others simply experience a headache. However, some have more intense symptoms, such as uncontrolled, undirected movements like flailing of limbs, loss of awareness or loss of consciousness.
Causes
The origin of seizures lays in malfunctioning brain cells, but according to the Epilepsy Foundations, in 7 out of 10 cases the actual cause of the malfunction is unknown. In cases where the origin is known, brain trauma of some sort is usually implicated, such as lack of oxygen, brain tumors, lead poisoning, or infections like encephalitis or meningitis.
Triggers
The Epilepsy Foundation reports that several characteristics of television displays can trigger seizures: flicker rate, rolling images, rapid flashing, contrast between the television brightness and background light source, brightness of the television screen and alternating patterns of different colors. For example, Science Daily describes an incident that occurred in 1997 in Japan. At 6:50 p.m., 685 people, mostly children, who were watching an episode of a popular television show called "Pocket Monsters" had simultaneous epileptic seizures. It was later determined that a rapid change between blue and red in the background triggered the mass seizures. The "Richmond Times-Dispatch" reports that in April of 2010, Samsung released an advisory regarding their 3-D televisions--the 3-D glasses apparently can cause a flickering effect that triggers seizures in some vulnerable viewers.
Interventions
Children with photosensitive epilepsy can reduce the likelihood of television-induced seizures through the proper, consistent use of anti-seizure medication such as valproic acid and avoidance of the triggers. Many children with photosensitive epilepsy can still view television. Certain precautions can minimize the risk of seizures, including watching the television in a well-lit room, keeping far back from the television, avoiding watching when tired, not watching for long periods of time, wearing polarized sun glasses and reducing the brightness of the screen.
Diagnosis
Neurologists can diagnose photosensitive epilepsy by monitoring an EEG while a child is exposed to specific light and pattern stimuli. Abnormal responses indicate vulnerability to seizures during television viewing.
