What's Actually Happening During a Seizure?

Jan 09, 2024

What's Actually Happening During a Seizure?

Seizures and Epilepsy

Seizures and epilepsy are related but distinct concepts within the field of neurology.

A seizure is a sudden, uncontrolled electrical disturbance in the brain. It can cause changes in behavior, movements, feelings, and levels of consciousness. Anyone can have a seizure under certain circumstances, such as extreme stress, high fever, lack of sleep, or alcohol withdrawal.

Epilepsy is a chronic neurological disorder marked by recurrent, unprovoked seizures. The term "unprovoked" means that the seizures are not triggered by a clear and reversible cause, such as alcohol withdrawal or extremely low blood sugar. People with epilepsy have an enduring predisposition to generate epileptic seizures. The diagnosis of epilepsy typically comes after a person has had at least two unprovoked seizures, or one unprovoked seizure with a high likelihood of further seizures, that were not caused by a general and reversible medical condition.

Understanding Brain Structure

The human brain is an intricate and complex structure that governs various functions ranging from movement to cognition, emotion, and consciousness. Here's a brief overview of the brain structure:

  1. Meningeal System: 

The meninges are three layers of protective tissue called the dura mater, arachnoid mater, and pia mater that surround the neuraxis, which includes the brain and spinal cord. The dura mater is the rigid outermost layer. The arachnoid mater is the middle layer, filled with cerebrospinal fluid, which helps cushion and protect the brain and spinal cord. The pia mater is the delicate innermost layer that closely follows the contours of the brain.

  1. Cortex and Neurons: 

The cortex is the brain's outermost layer, and a wrinkled appearance characterizes it. It's primarily composed of gray matter, which includes neurons. Neurons are the basic working units of the brain, designed to transmit information to other nerve cells, muscle, or gland cells. They are interconnected in complex ways and are crucial for all brain activities.

  1. Division of the Brain into Lobes: 

The brain is divided into four main lobes: frontal, parietal, occipital, and temporal. Each lobe is associated with different functions:

  • Frontal Lobe: 

Located at the front of the brain, the frontal lobe is involved in decision-making, problem-solving, and planning. It's also important for voluntary movement, speech production, and aspects of personality and emotional expression.

  • Parietal Lobe: 

Situated behind the frontal lobe, the parietal lobe processes sensory information from the body, including spatial sense and navigation (proprioception), temperature, taste, and touch.

  • Occipital Lobe: 

Located at the back of the brain, the occipital lobe is primarily responsible for vision.

  • Temporal Lobe: 

Positioned beneath the frontal and parietal lobes, the temporal lobe plays a crucial role in processing auditory information and is also important for memory.

Understanding the structure of the brain and its various components is fundamental to understanding how it functions and how different regions interact to produce behavior and cognition.

Seizures and Epilepsy: Understanding the Difference

Understanding the difference between seizures and epilepsy is important in neurology.

Seizures are sudden, uncontrolled electrical disturbances in the brain that may cause changes in behavior, movements, feelings, or consciousness. They are symptoms of a brain problem. Seizures can happen to anyone under certain conditions, such as high fever, severe head injury, lack of sleep, or alcohol withdrawal.

Epilepsy, on the other hand, is a chronic neurological disorder characterized by recurrent, unprovoked seizures. It is diagnosed when a person has had at least two unprovoked seizures (seizures not caused by a reversible or temporary medical condition) or one unprovoked seizure with a high likelihood of further seizures.

Seizures can be categorized into two main types: epileptic and non-epileptic seizures.

  • Epileptic seizures are caused by abnormal electrical discharges in the brain and are typically categorized into focal (affecting only one part of the brain) and generalized (affecting the whole brain).
  • Non-epileptic seizures (also known as pseudoseizures) resemble epileptic seizures but are not associated with abnormal electrical activity in the brain. Instead, they may be due to psychological factors and are often diagnosed when a person has seizures that are not improved with epilepsy medications.

The electroencephalogram (EEG) plays a crucial role in diagnosing epilepsy. It is a noninvasive test that records electrical signals in the brain. It can detect abnormal electrical activity associated with epilepsy and help differentiate it from other conditions. Small electrodes are attached to the scalp during an EEG to pick up the electrical signals. These signals are then graphed as waves and analyzed by a neurologist to determine whether the patterns are typical or indicative of epilepsy.

While seizures are individual episodes of uncontrolled electrical disturbances in the brain, epilepsy is a chronic condition characterized by recurrent, unprovoked seizures. The EEG is a critical tool in diagnosing epilepsy and differentiating it from other conditions.

Causes of Seizures

Seizures can be triggered by many factors, many of which are related to underlying health conditions or certain environmental stimuli. Here are some of the causes:

  1. Infections: 

Certain infections can cause seizures, mainly if they affect the brain. These include encephalitis (inflammation of the brain), meningitis (inflammation of the membranes around the brain and spinal cord), and certain viral infections.

  1. Metabolic and Structural Issues: 

Metabolic disturbances such as low blood sugar (hypoglycemia), low sodium levels (hyponatremia), low calcium levels (hypocalcemia), and high ammonia levels can trigger seizures. Similarly, structural problems in the brain, like brain tumors, cysts, or specific brain injuries, can also lead to seizures.

  1. Medications and Substances: 

Certain medications can induce seizures, especially when taken in overdose. Similarly, recreational drugs, such as cocaine, amphetamines, and some types of synthetic cannabis, can provoke seizures. Alcohol withdrawal after heavy and prolonged consumption can also lead to seizures.

  1. Blood-Related Issues and Fever: 

Severe anemia or other blood disorders can deprive the brain of oxygen, potentially leading to seizures. High fever, particularly in young children, can also cause what's known as febrile seizures.

  1. Stress and Genetics: 

Prolonged or intense periods of stress may trigger seizures in some individuals. Genetic factors also play a role, with certain types of epilepsy having a clear genetic cause. Genetic syndromes like Dravet syndrome or Lennox-Gastaut syndrome can cause some seizures.

It's important to note that in many cases, the cause of seizures remains unknown, despite thorough investigation. This is known as idiopathic epilepsy. It'sIt's also important to remember that not everyone who experiences a seizure has epilepsy, which is defined by recurrent, unprovoked seizures.

Phases of Seizures

Seizures can generally be divided into four distinct phases: prodrome, aura, ictal, and postictal. Each stage has unique characteristics and symptoms:

  1. Prodrome Phase: 

The prodrome phase occurs before the seizure and can last from several hours to days. All individuals with seizures do not experience this phase. During the prodrome phase, a person may undergo subtle changes in mood, behavior, or physical sensations such as headaches, irritability, or restlessness. These changes serve as a warning sign that a seizure may be imminent.

  1. Aura Phase: 

An aura is a brief, often subjective, sensory or cognitive disturbance immediately preceding the seizure. Auras are considered simple focal seizures, meaning they affect a small brain area. The symptoms experienced during an aura can vary widely depending on the part of the brain involved. Some common aura symptoms include visual disturbances (like flashing lights or blind spots), auditory hallucinations, a sudden sense of fear or déjà vu, or unusual tastes or smells.

  1. Ictal Phase: 

The ictal phase refers to the actual seizure. This phase can last from a few seconds to several minutes. During this phase, the person may experience various symptoms, depending on the type of seizure. These can range from sudden, involuntary muscle contractions, loss of consciousness, and convulsions (in the case of a tonic-clonic seizure) to brief episodes of unresponsiveness, staring, and repetitive movements (in the case of an absence seizure).

  1. Postictal Phase: 

The postictal phase occurs immediately after the seizure and can last for a few minutes to several hours. During this recovery period, the person may experience confusion, drowsiness, fatigue, headache, muscle aches, and temporary memory loss. It'sIt's not uncommon for the individual to have little or no recollection of the seizure.

Each seizure phase provides essential information for healthcare providers, as it helps them determine the type of seizure, possible triggers, and appropriate treatment options.

Types of Seizures

Seizures can be broadly classified into focal (also known as partial) seizures and generalized seizures. Each category has unique characteristics and can be further subdivided into various types.

Focal Seizures: 

Focal seizures start in one area of the brain. They are further classified into:

  • Focal Motor Seizures: 

These seizures often cause movements of a specific body part, such as twitching or jerking. Jacksonian March is a focal motor seizure where the jerking movement starts in one part of the body and then progresses to other parts.

  • Focal Sensory Seizures: 

Sensory seizures may affect any of the senses. People experiencing a sensory seizure might hear sounds that aren't there, see flashes of light, or feel tingling sensations.

  • Focal Autonomic Seizures: 

These seizures involve the parts of the brain that regulate body functions we don't consciously control, such as heart rate or digestion. Symptoms can include changes in skin color, sweating, or feeling like your heart is racing.

Generalized Seizures: 

Generalized seizures involve all areas of the brain simultaneously. They are further classified into:

  • Absence Seizures (Petit Mal): 

Characterized by brief, sudden lapses of consciousness, often resulting in staring or subtle body movements. They are most common in children.

  • Tonic Seizures: 

These cause stiffening of the muscles, often those in the back, arms, and legs.

  • Atonic Seizures (Drop Attacks): 

Lead to a loss of muscle control and can cause sudden collapse or falls.

  • Clonic Seizures: 

Characterized by repeated, jerky muscle movements, typically in the face, neck, and arms.

  • Myoclonic Seizures: 

Involve sudden, brief jerks or twitches of the muscles.

  • Tonic-Clonic Seizures (Grand Mal): 

The most noticeable type involves a combination of muscle stiffening and jerking.

  • Febrile Seizures: 

Seizures in children are associated with a high fever. These are not necessarily indicative of epilepsy.

Understanding the types of seizures can provide insight into the best treatment options and how to respond appropriately when a seizure occurs. A healthcare professional should always be consulted for accurate diagnosis and treatment.

Treating Seizures

When treating  seizures, the first step is identifying the underlying cause, especially for non-epileptic seizures. Non-epileptic seizures might be caused by conditions such as low blood sugar, an infection, a high fever, or severe psychological stress. Addressing these underlying conditions often helps to control or eliminate seizures. For example, if seizures are due to a specific medication or substance, changing or discontinuing it may help prevent further seizures.

On the other hand, if seizures are epileptic, the primary treatment strategy usually involves anti-seizure medications, also known as antiepileptic drugs (AEDs). There are many different AEDs, and the choice of which one to use is based on the type of seizure, the age of the individual, possible side effects, cost, and if a woman is pregnant or planning to become pregnant.

For some people, seizures might be well-controlled with medication, while others might continue to experience seizures despite trying multiple drugs. In such cases, other treatment options may be considered:

  • Dietary Therapy: 

The ketogenic diet, a high-fat, low-carbohydrate diet, has been found to reduce seizure frequency in some individuals, particularly children with certain types of epilepsy.

  • Surgery: 

Surgery may be an option if seizures are due to a specific brain area and if this area can be safely removed without disrupting vital functions.

  • Neurostimulation Devices: 

Devices like the vagus nerve stimulator (VNS), responsive neurostimulation system (RNS), or deep brain stimulation (DBS) can be implanted to help reduce seizure frequency.

  • Cannabidiol (CBD): 

CBD, a compound derived from the cannabis plant, has been shown to reduce seizure frequency in certain types of epilepsy, like Dravet syndrome and Lennox-Gastaut syndrome.

The treatment of seizures is personalized and depends on many factors. It requires regular follow-ups with a healthcare provider to ensure optimal management.

Final Thoughts

Seizures and epilepsy are related neurological conditions; seizures are sudden, uncontrolled electrical disturbances in the brain, while epilepsy is a chronic disorder characterized by recurrent, unprovoked seizures. Seizures can be caused by various factors, such as infections, metabolic or structural brain issues, certain medications, stress, or genetic factors, and they typically occur in four phases: prodrome, aura, ictal, and postictal.


Seizures are categorized as focal, starting in one brain area, or generalized, involving all areas. Treatment for seizures depends on the underlying cause, with epilepsy commonly managed by anti-seizure medications. However, other treatments like dietary therapy, surgery, neurostimulation devices, and cannabidiol may also be effective. Understanding these conditions is crucial for improving the quality of life for those affected.