Overview of Epilepsy

There are several types of epilepsy, typically classified based on the type of seizure and its origin in the brain. Here are the main types:

Focal onset seizures:

Focal onset seizures begin in one location of cells in the brain or one side of the brain. This is known as a Partial onset seizure. There are two types of focal seizures. 

Focal Onset aware seizures :

In this type of seizure, a person faces seizure when the person is awake. It is also known as a simple partial seizure. 

Common Symptoms of Focal Aware Seizures or Focal Simple Partial Seizure.

🔹 Motor Symptoms:

Jerking or twitching in one part of the body (e.g., hand, arm, face)

Muscle stiffness or weakness

Repetitive movements (e.g., lip-smacking, hand rubbing)

🔹 Sensory Symptoms

Tingling, numbness, or “pins and needles”

Visual disturbances (flashes of light, distortions)

Auditory hallucinations (buzzing, ringing)

Unusual smells or tastes

Feeling of heat or cold

🔹 Autonomic Symptoms

Changes in heart rate

Sweating

Goosebumps

Nausea or abdominal discomfort

🔹 Psychic Symptoms

feeling something is strangely familiar or unfamiliar

Sudden fear, anxiety, or euphoria

Distorted perception of time or reality

These seizures are typically brief, lasting seconds to a couple of minutes, and may serve as a warning (aura) before a more severe seizure.

Focal onset impaired awareness:

Focal Onset Impaired Awareness Seizures (previously called complex partial seizures) begin in one part of the brain (focal onset) and involve altered or impaired consciousness or awareness during the seizure. The person may appear awake but is not fully responsive or aware of their surroundings.

Common Symptoms of Focal Onset Impaired Awareness Seizures:

🔹 Impaired Awareness

Blank staring or unresponsiveness

Confusion during or after the seizure

No memory of the event afterward

🔹 Automatisms (Involuntary Movements)

Lip smacking

Chewing or swallowing

Picking at clothes or objects

Repetitive hand or finger movements

Wandering or walking aimlessly

🔹 Behavioral Changes

Sudden emotional outbursts (fear, anger, laughter)

Inappropriate responses or speech

Repeating words or phrases (if speech is possible)

🔹 Aura (Warning Symptoms) Beforehand

Some individuals may experience a focal aware seizure (aura) immediately before the impaired awareness sets in. These could include:

Strange smells, tastes, or sensations

Visual disturbances

Rising feeling in the stomach

Sudden fear 

Duration and Recovery: Typically lasts 1–2 minutes

Recovery may involve confusion, fatigue, or disorientation (postictal phase)

Generalized onset Seizures:

This type seizures affect a wide aspect network of cells of both sides of the brain at same time.

There are six types of generalized seizures.

1) Absence seizures: 

Absence seizures (formerly called petit mal seizures) are a type of generalized seizure that involves a brief, sudden lapse in consciousness. They are most common in children & adults. In this type of seizure, the affected person stares into space or blank stares.

Key Features of Absence Seizures:

 Sudden Loss of Awareness

The person appears to “zone out” or stare blankly into space.

 They do not respond when spoken to or touched.

 Brief Duration

Typically lasts 5 to 15 seconds, rarely more than 30 seconds.

Can happen many times a day.

 Automatisms (Subtle Movements)

Eye blinking

Lip smacking

Chewing motions

 Small hand movements

 No Postictal Confusion

Unlike other types of seizures, the person quickly returns to normal afterward, with no confusion or memory of the event.

2) Atonic seizures:

This is  also called drop attacks. It is a type of generalized seizure where the person experiences a sudden and brief loss of muscle tone. This can cause them to collapse, fall, or drop their head or limbs unexpectedly.

Key Features of Atonic Seizures:

•  Sudden Loss of Muscle Tone
• May affect the whole body or just certain muscles (e.g., neck, legs).

Can cause:

• Sudden collapse or fall to the ground
• Head nodding or jaw dropping
• Dropping of objects from the hands

Very Brief Duration

• Usually lasts less than 15 seconds.
• Person typically recovers quickly, but may be confused or dazed briefly.

 High Risk of Injury

• Because of the sudden fall, there’s a risk of head injuries or bruises.
• Helmets may be recommended in severe cases for safety.

 Awareness

Varies: some remain conscious, others may briefly lose awareness.

Common Causes or Associations:

• Often seen in epilepsy syndromes like Lennox-Gastaut syndrome.
• Typically resistant to treatment and may require medications, diet therapy (like ketogenic diet), or vagus nerve stimulation (VNS).

3) Tonic seizures:

It is type of generalized seizure characterized by a sudden stiffening (increased muscle tone) in the muscles, often affecting the arms, legs, or entire body. They usually last less than 20 seconds and can occur during sleep or while awake.

Key Features of Tonic Seizures:

 Muscle Stiffness

Sudden, sustained muscle contractions cause the body or limbs to stiffen and become rigid.

Often affects the back, arms, and legs. May cause the person to fall backward if standing (unlike atonic seizures, where they collapse forward or go limp).

 Short Duration

• Typically lasts 10 to 20 seconds.
• Recovery is usually quick, but the person may be confused or tired afterward.

 Awareness

• Can occur with or without loss of consciousness.
• If consciousness is impaired, the person may not remember the event.

 Common During Sleep

Tonic seizures are often nocturnal, which can make them harder to recognize.

Associated Conditions:

Common in certain epilepsy syndromes, especially Lennox-Gastaut syndrome.

Often seen in people with developmental or neurological disorders.

Risks and Complications:

Falls or injuries due to sudden muscle stiffening, especially if standing or walking at onset.

May require protective measures like helmets if frequent and severe.

4) Clonic seizures:

It is a type of generalized seizure characterized by repetitive, rhythmic jerking movements of the muscles. These movements typically affect both sides of the body and are caused by repeated contraction and relaxation of muscles.

Key Features of Clonic Seizures:

🔹 Rhythmic Jerking Movements

• Repetitive muscle contractions and relaxations.
• Usually affects the arms, neck, and face, but can involve other parts of the body.

🔹 Moderate Duration

• Typically last a few seconds to a minute.
• Less common than tonic-clonic seizures.

🔹 Awareness

• Loss of consciousness is common, but not always present.
• The person may be confused or drowsy after the seizure (postictal phase).

Clonic vs. Tonic-Clonic Seizures

Clonic seizures involve only the jerking phase.

Tonic-clonic seizures have a tonic phase (stiffening) followed by a clonic phase (jerking).

Who Gets Clonic Seizures?

More common in infants and young children, but can occur at any age.
May be part of certain epilepsy syndromes or occur after brain injury, infection, or metabolic issues.

5) Tonic-clonic seizures:

It is formerly known as grand mal seizures) are the most well-known and dramatic type of generalized seizure, involving both muscle stiffening (tonic phase) and rhythmic jerking (clonic phase). They affect the entire brain and typically result in loss of consciousness.

Phases of a Tonic-Clonic Seizure:

      1. Tonic Phase (10–20 seconds):

• Sudden loss of consciousness .
• Body stiffens, often causing the person to fall if standing.
• Possible cry or grunt as air is forced out of the lungs.
• May stop breathing briefly, resulting in a bluish face or lips.

  2. Clonic Phase (30–60 seconds):

• Rhythmic jerking of the limbs and face
• Possible tongue biting or incontinence
• Breathing usually resumes but may be irregular

  3. Postictal Phase (minutes to hours):

• Deep sleep or confusion
• Headache, fatigue, or soreness
• No memory of the seizure

Key Characteristics:

• Involves the entire body.
• Often triggered by missed medications, sleep deprivation, flashing lights (in photosensitive epilepsy), or stress.

Can be dangerous due to the risk of falls or injury.

Medical Considerations:

Emergency help is needed if the seizure lasts longer than 5 minutes, if it’s the person’s first seizure, or if they don’t regain consciousness afterward.

6) Myoclonic seizures :

Myo means muscle and clonus means muscle jerking. Myoclonic seizures are a type of generalized seizure that involve sudden, brief, shock-like muscle jerks. These jerks are typically rapid and may affect the arms, legs, shoulders, or entire body. Unlike other seizure types, consciousness is usually not impaired.

Key Features of Myoclonic Seizures:

 Muscle Jerks

• Sudden, involuntary jerks of one or more muscle groups
• Often occur bilaterally (on both sides of the body)
• May be so subtle they look like a quick twitch or so strong they cause the person to drop something or fall. 

Very Brief Duration

• Typically last less than 1–2 seconds
• May occur once or in clusters over several minutes
  

 Awareness

• Consciousness is usually preserved, though the person may be startled or surprised
  
• No postictal confusion (no recovery phase is typically needed)

Common Times of Occurrence

• Frequently happen soon after waking up.
• Often triggered by fatigue, stress, or flashing lights.

Associated Conditions

• Frequently seen in Juvenile Myoclonic Epilepsy (JME).
• Can also occur in progressive myoclonic epilepsies, which are rare and often more severe.