Photosensitive Epilepsy: A Closer Look At Light-Induced Seizures

Introduction

Epilepsy is a neurological disorder that occurs due to abnormal electrical activity of the brain. It is characterized by abnormal body movements, unusual patient behavior, and a loss of awareness. Multiple etiological factors are involved in epilepsy. Photosensitive epilepsy is one form of epilepsy that is triggered by light. Different light patterns, such as flickering and interchanging lights, can cause seizures (abnormal involuntary body movements) in patients with photosensitive epilepsy. This is a rare form of epilepsy commonly seen in children and adolescents who have generalized epilepsy (abnormal movements of the entire body). Almost three percent of individuals with epilepsy suffer from this type of disease.

What Is Photosensitive Epilepsy?

Photosensitivity is extreme sensitivity towards light, and the light sources may be artificial or UV (ultraviolet) radiation from the sun. Photosensitive epilepsy is when bright flickering lights trigger seizures. Flashing and contrasting lights that disturb the eyes also cause seizures. The leading cause of photosensitive epilepsy is a photo paroxysmal response in the affected individual.

What Is a Photoparoxysmal Response?

It is an abnormal response to flickering lights seen in photosensitive individuals when recorded on an electroencephalogram. The electroencephalogram records the electrical activity of the brain. The vision of an epileptic person is stimulated with bright flickering light. A response is recorded on the electroencephalogram in spikes and waves. This abnormal electroencephalographic response may be due to hyperexcitability (exaggerated response) of the visual and motor system.

What Are the Triggering Factors of Photosensitive Epilepsy?

The brain is a significant organ that controls all voluntary and involuntary functions of the body. It receives and sends signals from the entire body through nerves. If there is any disturbance in this signal transmission, it leads to the development of neurological disorders. Epilepsy occurs mainly due to damage to the brain. Genetics plays a vital role in photosensitive epilepsy.

The common triggers of photosensitive epilepsy include -

• Playing video games.

• Using computers and mobile phones.

• Watching television (TV).

• Attending concerts that have bright focus lights.

• Watching fireworks.

• Watching movies in cinema theaters.

How Common Is Photosensitive Epilepsy?

Photosensitive epilepsy is relatively rare compared to other types of epilepsy. It is estimated that photosensitivity affects approximately three to five percent of people with epilepsy. Photosensitive epilepsy is more common in children and adolescents than in adults, with the majority of cases being identified in individuals under the age of 20. The condition appears to affect both males and females equally.

Which Type of Seizures Are Seen in Photosensitive Epilepsy?

Patients who have light-induced epilepsy show three types of seizures -

• Generalized tonic-clonic seizures (grand mal epilepsy).

• Absence seizures.

• Myoclonic seizures.

1. Generalized Tonic-Clonic Seizures (Grand Mal Epilepsy) -

This type of seizure occurs in five stages. Physical changes throughout the body characterize it -

• Flexing or contraction of the body.

• Extension.

• Tremors or shaking.

• Clonic period (contraction and relaxation of muscles).

• The postictal period comprises tiredness, fatigue, headache, body ache, and problems with speech.

2. Myoclonic Seizures - These seizures are of short span and occur as jerks, including a particular muscle group. The patient experiences quick, uncontrolled muscle jerks and may show unusual clumsiness. They are commonly seen in patients with photosensitive epilepsy.

3. Absence Seizures - The patient becomes still and stares blankly when this type of seizure occurs. The patient may stop doing any physical activity and stand still. After some seconds, they may resume what they were doing.

It is important to note that not all individuals with epilepsy who are exposed to visual stimuli will experience seizures. Photosensitivity is a specific sensitivity to certain visual patterns or flickering lights, and only those individuals who are photosensitive will be susceptible to seizures triggered by these stimuli.

What Are the Signs and Symptoms of Photosensitive Epilepsy?

The following are general symptoms experienced by patients with epilepsy -

• Feeling dizzy and falling.

• Headache.

• Blurred vision.

• Mood changes.

• Nausea.

• Tightening of the muscles.

• Skin crawling (a feeling of ants crawling on the skin).

• An increased heart rate.

• Unusual head movements.

• Numbness or tingling sensation in the extremities.

How to Diagnose Photosensitive Epilepsy?

• The physician notes a detailed medical history and the signs and symptoms experienced by the patient. Physical examination is done to check the tone and strength of muscles. The doctor even checks if the patient can walk properly and for balance and coordination.

• A special test called an electroencephalogram (EEG) is ordered to record abnormal electrical brain activity.

• Brain imaging scans such as MRI (magnetic resonance imaging) and CT scan (computed tomography) can be done in cases that require examination of the brain to detect significant abnormalities (brain tumors).

What Is the Treatment for Photosensitive Epilepsy?

This type of epilepsy can be managed in the following ways -

• Avoidance of Triggers - Educating the patient to make specific changes in lifestyle to avoid seizure-triggering factors and adopting methods to prevent exposure to them in daily life. Avoiding places with high-intensity lights, such as concerts, nightclubs, and movie theaters. Using protective eye gear when going out in the sun. Installing dim lights in the house.

• Modifying the Use of Light-Emitting Devices - Watch television from a sufficient distance and use a remote control to change the channels. Reduce the brightness of the mobile phone or refrain from using it in the dark.

• Antiepileptic Drugs - Patients with photosensitive epilepsy may require to take minimum dosage medications life-long. Failing to do so will cause the recurrence of seizures even in patients who have been free of attacks for a long time. Patients respond well to treatment with antiepileptic drugs and lead healthy lives.

• Adequate Rest - Patients with epilepsy require plenty of sleep and rest. Any significant physical activities that can cause undue stress on the body should be avoided.

• Avoid Intoxicants - Abstain from smoking and consumption of alcohol.

Conclusion

Patients usually respond well to antiepileptic medications. Changes in lifestyle and adopting methods to avoid triggering factors lead to a good prognosis. The appearance of seizures gradually reduces as the patient grows old. Regular medications will be required to be taken life-long to prevent the occurrence of seizures. Photosensitive epilepsy is the most common cause of reflex epilepsy. The occurrence of this form of epilepsy has increased ever since video games were introduced. More cases are coming forward as many children are exposed to these triggers. Medications will help rescue the light sensitivity considerably and help the patient carry out functions in daily life.