Often, people sense that something is about to happen to them right before a seizure. During seizures, abnormal signals travel through the brain. These signals cause different physical effects depending on which parts of the brain are involved and how far the signals fan out. Some people have violent seizures that knock them to the floor unconscious and twitching. Others experience less severe seizures that may only blank them out for a few seconds or more.
Some mild seizures pass so quickly that it seems the person is just daydreaming.
It is not uncommon for this so-called photosensitivity to run in families. Some drugs, like valproate, are helpful in reducing photosensitivity and preventing these seizures. Some people simply outgrow epilepsy or are able to evade seizures by avoiding the stimuli that provoke them. Seizures are the worst but not the only problems for video game fanatics. The houseguest, who had not previously played nintendo, remained riveted to the set for 5 straight hours, pressing a button with her thumb over and over again.