Photosensitive Epilepsy (PSE) is defined by seizures that are caused by visual stimuli that form patterns in time or space, such as flashing lights, bold, regular patterns or regular moving patterns. It affects about one out of every 4,000 people in the world. It is important to note, however, that people with or without epilepsy can become disoriented, uncomfortable or ill as a result of flashing or patterned lights. This does not always imply that they suffer from photosensitive epilepsy. There are signs and symptoms that you can keep a lookout for, to tell if you are living with this condition.
Symptoms and Signs of Photosensitive Epilepsy
When patients with photosensitive epilepsy are exposed to visual stimuli, they experience epileptic seizures. Many patients have reported experiencing an “aura” or a strange feeling before a seizure, which could be an indicator for the patient to step away from the trigger stimuli. As mentioned, seizures could be triggered by flashing lights or constantly shifting or alternating images such as in clubs, near emergency vehicles, near overhead fans, in action movies or television shows, etc. Static spatial patterns like stripes and squares can also cause seizures.
The cause stimuli of several people with photosensitive epilepsy share many similar characteristics.
1. Luminance contrast is normally strong in the patterns (bright flashes of light alternating with darkness, or white bars against a black background).
2. Patterns of some colours affect certain patients more than patterns of other colours.
3. The exact timing of a pattern in time or space is critical and varies from one person to the next. For example, a patient may have seizures when lights flash seven times per second, but not when lights flash twice per second or twenty times per second.
4. Stimuli that take up the entire visual field are more likely to trigger seizures than those that only take up a portion of it.
5. Stimuli that are seen by both eyes are much more likely to trigger seizures than stimuli that are only seen with one eye. Covering one eye in some cases may allow patients to avoid seizures when presented with visual challenges. Some patients are more alert when they shut their eyes; others are more sensitive when they open their eyes.
6. Finally, alcohol intake, sleep deprivation, sickness, and other sources of stress all increase the sensitivity to seizures.
Other Important Causes of Photosensitive Epileptic Seizures
Television has long been the most common cause of seizures in people with PSE. The minuscule constant shifting of light is hidden from the naked eye, but in the long run, it can affect the patient. Especially viewing television in a dark room, at close range, or when the television is out of adjustment and displaying a rapidly flickering picture is particularly dangerous for people with PSE.
Modern digital television sets, which can’t be tampered with in this way and refresh the image on the screen at a high rate, pose a lower risk than older analogue television sets. Some people, particularly those with cognitive impairments, self-induce seizures by moving their fingers in front of their eyes in bright light or by other means. However, the majority of people with PSE do not. It is also noted that some people with PSE, especially children, can develop an uncontrollable obsession with seizure-inducing television images, to the point that they must be physically removed from television sets. Children find it particularly hard to understand what their condition is all about. This is why there is a large selection of available books to explain epilepsy to a child.
The Use of Fluorescent Lighting
Fluorescent lighting has a sufficiently high flicker rate to minimise the incidence of problems when it is working properly. On the other hand, a defective fluorescent light will flicker at a much slower rate and cause seizures. Newer high-efficiency compact fluorescent lamps (CFLs) with electronic ballast circuits work at far higher frequencies than the human eye can detect, though faulty lights can still cause seizures.
How Can You Treat Photosensitive Epilepsy
The best course of treatment is to get started on anti-epileptic drugs (AEDs) that treat generalised seizures and normally work well for photosensitive epilepsy. It is also advised to take precautionary measures and avoid seizure causing stimuli. The Inspyre™by SmartMonitor detects repetitive shaking motion such as those caused by PSE seizures. It signals the user’s phone to instantly send a text and phone call alert to whomever the user designates, such as multiple family members, doctors and other care providers. These alerts include the date, time, location, and duration of the event. It can also be useful to set medication reminders. Help is just a button away! Follow us on Facebook and Instagram for interesting posts, information and help on how to live with epilepsy.