Photosensitive epilepsy is a common type of epilepsy in children that is triggered by light. Frequency, type of light, and proximity of light all play a role in photosensitive epilepsy. Photosensitive epilepsy is typically accompanied by another type of epilepsy such as generalized epilepsy or juvenile myoclonic epilepsy. One rare form of this epilepsy is called Sunflower Syndrome. Sunflower Syndrome is a form of self-induced photosensitive epilepsy that can consistently elicit seizures. These seizures are self-induced by standing in the sunlight and waving hands fast in front of the face. This causes a photic like flashing that will trigger epileptic discharges. The following will discuss its epidemiology, symptoms and clinical features, the neurodiagnostics, and treatment options.
Epidemiology/Incidences
Using bright flashing lights has been a method of evoking epileptiform discharges in an electroencephalogram since the 1940s (Specchio et al., 2011). Seizures can be triggered by flickering sunlight, artificial light, video games, and some TV shows/movies. Therefore, people with photosensitive epilepsies can sometimes have difficulty performing some of the daily life activities. The prevalence of photosensitive seizures was not big until there was a series of Nintendo and TV related incidences of triggering seizures in the UK in 1992. Then again, in 1997 in Japan when the premier of Pokémon, a hit kids cartoon with bright red and blue flashing lights, caused over 200 children to have a seizure (Trenité, 2006).
Photosensitive seizures and epilepsies affect 1 in 4,000 of the population. Two-thirds are women and the peak age at onset is 12–13 years. Clinical photosensitivity was found in 2% of patients of all ages presenting with seizures and 10% of patients presenting with seizures in the 7–19year age range (Panayiotopoulos, 2005). In most cases of photosensitive epilepsy, there is an underlying epilepsy associated with it. Juvenile myoclonic epilepsy, absence epilepsy, and West and Lennox syndrome have a possibility of being positive for a photic response that has been recorded on an EEG. The following people with these types of epilepsy have a chance of having a photic response including a photic induced seizure; Myoclonic epilepsy at 30%, absence epilepsy at about 18%, and West/Lennox syndromes at 17% (Trenité, 2006). Sunflower Syndrome also classifies as a self-induced photosensitive epilepsy, which means that the person will trigger the seizure themselves. Self- induced seizures are most commonly seen in adolescents ranging from infancy to early childhood, rarely ever is it seen in adults. It is also very female predominant with about 80% of cases being young females (Panayiotopoulos, 2005). It has been proven that it does have genetic predisposition. Several genes may be involved but neurologist don’t know to what extent yet. It may relate to chromosomes 2, 6,7, and 16. Families with a history of myoclonic epilepsy and absence epilepsy show a higher chance of inheritance of photic related responses, but not necessarily Sunflower Syndrome specifically (Trenité, 2006).
Symptoms/Clinical Features
Sunflower Syndrome will present itself as a seizure disorder with high sensitivity to light. Sunflower syndrome has been seen in both people who are cognitively normal/well-functioning and people with a cognitive delay. The individual will be out in the sunlight and start waving their hand back and forth in front of their face in a fan like motion. This will trigger a seizure, absence, and myoclonic jerks are the most commonly seen. People can induce the seizure consciously or unconsciously; it can become a second nature to start waving their hand as soon as sunlight is present. Some patients have reported that it evokes a euphoric or relaxing feeling when the epileptiform discharges occur which encourages the patient to continue doing it (Belcastro, 2013). When watching someone with this syndrome, one should clearly be able to see the waving of the hand and then the participator will either be the patient will stare off for a period of time or start to have myoclonic jerks. Myoclonic jerks are described as sudden muscle contractions, followed by muscle relaxation. It often can look similar to twitching and is uncontrollable (NINDS, 2012). These symptoms can be easy to see if one knows what they are looking for, but the only way to prove that it is clinically relevant is to have an electroencephalogram performed.
Evaluation/Tests/Correlation with Neurodiagnostic Studies
When a patient is being tested for Sunflower Syndrome it is common practice to have an electroencephalogram (EEG) completed. One way to test for Sunflower Syndrome with an EEG, is to use a photic machine to do photic stimulation. Photic stimulation would be performed in a dark room with the lights flashing at a frequency between 3 and 50 Hz, and with the light source approximately 30cm from the nasion (Capovilla et al., 2006). According to other studies done relating to photosensitive epilepsy most patients react to a frequency between eight and thirteen hertz (Specchio et al., 2011). The photic machine will start at its slowest frequency then build every five seconds until the optimal frequency is achieved.
The EEG should appear relatively normal when the patient is awake with their eyes open and when their eyes are closed. Once the optimal frequency is achieved one would expect to see a generalized spike and wave discharge. In multiple cases it has been a generalized 3-4 HZ spike and wave discharge, but it is possible to have a higher hertz discharge (Belcastro, 2013). The other way to test for Sunflower Syndrome would be to bring the patient out into the sunlight and have them trigger a seizure by waving their hand in front of their face while looking at the sun. Ideally it should show the same EEG correlation as if the patient were performing the test in a lab with a photic machine. However, the disclaimer to this syndrome is results on the EEG are very dependent on what the patient’s previous disposition is. If the patient has had a previous EEG it would be ideal to refer back to that for a baseline reading, in case abnormalities are already present.
Figure 1: Generalized 3-4-Hz spike-waves evoked by waving a hand in front of the eyes, while looking at sunlight
Treatment/Management
There is no true cure for epilepsy, therefore there is no cure for Sunflower Syndrome, there is only management. The most common antiepileptic drugs have been tested but none have specifically helped with stopping all the epileptic discharges associated with photosensitive epilepsy (Trenité, 2006). However, the different type of lenses, like sunglasses have proven to be some help. Different lens colors and transmittance can change the light just enough that it can decrease and in some cases even stop the light from triggering epileptiform discharges. A study was performed in Italy in 1999 by Capovilla, he tested photosensitivity suppression with intermittent photic stimulation while the patients wore different lenses. Four different lenses were tested, and only one proved to be the most effective, it is called Z1(blue lens). Age, sex, and type of epilepsy did not have any effect on the Z1 lens ability to inhibit epileptiform discharges. In 68% of patients using the Z1 lenses, there were no epileptiform discharges when tested with light, and 16% of the patients had reduced discharges (Capovilla et al., 2006). The other choice of management would be avoidance. The patient should attempt to stop triggering their seizures when they are in the sunlight. As the child gets older self-control becomes easier so they will not trigger them as much.
Conclusion/Summary
Sunflower Syndrome is a self-induced photosensitive epilepsy. This epilepsy is considered self-induced because the patient will stand outside in the sunlight and wave their hand in front of their face. This causes the light to flicker, which in result triggers a seizure. The seizures can present themselves as staring spells, or myoclonic jerks. In some patients, it can cause a euphoric feeling so they continue to induce these seizures. It is commonly seen in adolescents, especially in the female population. There is no true known cause of it, but it is speculated that it could be genetically linked to several chromosomes. Most commonly the patient will already present with a different form of epilepsy, absence, and myoclonic epilepsy are the most popular. There is no specific treatment for Sunflower Syndrome. Antiepileptic drugs will help with the patient’s epilepsy but do not seem to have an effect on the photic stimulated epileptic discharges that sometimes result in a seizure. There are however special lenses called Z1, they are a blue tinted lens that has significantly decreased the number of seizures people can get from being in the sunlight. Sunflower Syndrome is a rare form of epilepsy, there is a lot more knowledge to learn about as more cases appear in the future to come. Hopefully, epilepsy research continues to keep an eye on Sunflower Syndrome so that it can become better understood in future generations.
Written by: Caitlin Albers (2016)
References:
Belcastro, V., Striano, P. (2013). Self-induction seizures in sunflower epilepsy: a video-EEG report. Epileptic Disorders. 2014;16(1):93-95. doi:10.1684/epd.2014.0630.
Capovilla, G., Gambardella, A., Rubboli, G., Beccaria, F., Montagnini, A., Aguglia, U., . . . Tassinari, C. A. (2006). Suppressive Efficacy by a Commercially Available Blue Lens on PPR in 610 Photosensitive Epilepsy Patients. Epilepsia, 47(3), 529-533. doi:10.1111/j.1528-1167.2006.00463.x
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