Types and Triggers of Epileptic Seizures
Disclaimer: Not medical or professional advice.
Epilepsy is a chronic brain disorder that causes sudden epileptic seizures. The human brain contains about 86 billion nerve cells (neurons). Most of them are excitatory neurons. Their function is to transmit messages to nerve bundles that control movement, thoughts, and body functions. Inhibitory neurons constitute about 20 percent of brain cells.
They play an important role in blocking the function of excitatory nerve cells. The balance between excitation and inhibition is considered to be of significant importance for proper brain function. This can be compared to the applause of the audience in an auditorium. As soon as the performance is over, the crowd starts to clap randomly without a rhythm. Everyone does it in their own way. This phenomenon is known as white noise, which represents the normal function of neurons in the brain.
The audience gradually syncs to the rhythm and the sound of applause becomes louder. Something similar happens in the human brain during an epileptic seizure. A group of nerve cells with an abnormal rhythm of work (epileptic focus) signals it to the nearest neurons. An intense burst of electrical activity causes messages between cells to get mixed up and results in an epileptic seizure.
Classification of Epileptic Seizures
The manifestation and severity of an epileptic seizure depend on which part of the brain has an abnormal activity of nerve cells. In 2017, the International League Against Epilepsy (MLBE) developed a new classification system for seizures.
- The initial classification is by type of onset: Generalized onset, Focal onset, Unknown onset.
- All seizures are then divided according to motor manifestations (whether the patient has convulsions).
- Focal seizures are classified by level of awareness using a separate classification (knowledge of self and environment during the seizure).
Generalized-onset Seizures
A generalized-onset seizure affects areas in both hemispheres of the brain. During these seizures, the person loses awareness and consciousness.
Generalized-onset Motor Seizures
- Tonic-clonic seizures (Grand Mal Seizure) are what most people think of when they hear the word Epilepsy. The seizure begins with a tonic phase, where the person cries out due to a spasm of the vocal cords. Then, the muscles of the arms, legs begin to jerk during the second phase of the seizure, known as the clonic part. The seizure usually lasts a few minutes. After the seizure, the person may feel tired or sleepy. Besides, the person may not remember having a seizure and may not recognize the people nearby.
- Tonic seizures are relatively rare. During the tonic seizure, a person might have the head bent back with the arms and legs straightened. If standing, the person may fall to the ground. The normal state of consciousness and muscle tone returns immediately afterward.
- Atonic seizures are a fairly uncommon type of epileptic seizure (less than 1% of all seizures). This type of epileptic seizure involves a sudden loss of muscle tone and typically causes a person to become limp and fall slowly. These seizures do not cause convulsions. Atonic seizures often result from severe brain damage.
- Myoclonic seizures are brief, sudden, involuntary contractions that can involve a part of the body, such as an arm or head. It can also affect the whole body. Sometimes myoclonic seizures can cause a person to fall, but the seizure stops immediately after the fall.
Generalized-onset Nonmotor Seizures
The French word Absence accurately characterizes the main symptom of this type of seizure — a short lapse of consciousness without convulsions. With this type, a person may stare into space for 5-20 seconds and not respond to external stimuli. When the seizure passes, the person returns to normal. Absence seizures can happen several times a day and anywhere: at work, at home, or in transport. The main difficulty associated with this type of epileptic seizure is that it can be confused with inattention or daydreaming. For that reason, they often go overlooked. Epilepsy specialists and neurologists also call absence seizures Petit Mal.
Focal-onset Seizures
Focal-onset seizures occur in one hemisphere and easily turn into generalized-onset tonic-clonic seizures. This process occurs so rapidly that the patient does not even notice the focal symptoms.
Depending on clinical symptoms, focal-onset seizures can be divided into several groups.
- Autonomic dysfunction — gastrointestinal sensations, a sense of heat or cold, flushing, sexual arousal, and goosebumps.
- Behavior arrest — a person appears dazed and suddenly stops all activity.
- Cognitive dysfunction — speech disorders, déjà vu, hallucinations, illusions.
- Emotional dysfunction — unexplainable feelings of anxiety, fear, joy.
- Sensory dysfunction — a person can smell pleasant or foul smells, hear noise or voices, see flashing or flickering lights or spots.
Triggers for Epileptic Seizures
Epileptic seizures usually occur randomly and are completely unpredictable. However, some patients notice certain conditions that can trigger seizures.
- Irregular consumption of antiepileptic drugs or unauthorized dose reduction.
- Disruption of daily rhythms. A patient with epilepsy should get at least 7-8 hours of continuous sleep a day. Stress leads to disruption of the daily routine, poor sleep, and emotional outburst.
- Flashing light causes seizures in 5% of people with epilepsy. Flashing light will not be dangerous, if a person has never had a seizure because of headlights, rapidly changing images on the screen, flickering lights.
- Women with epilepsy report an increase in seizures during periods.
The most important things for a patient with epilepsy are regular doctor visits and therapy. If left untreated, seizures can result in serious injuries. People with epilepsy often experience difficulties with social functioning. They also refuse to play sports, become introverted and anxious.