Seizure Types – Epilepsy: The Untold Side

Epileptic seizures can look very different from one person to another. Some involve convulsions, but many do not. A seizure may cause a brief change in sensation, memory, behaviour, movement, responsiveness or consciousness, and some signs can be so subtle that other people barely notice them.

The International League Against Epilepsy (ILAE) updated its seizure classification in 2025. The current system has four main seizure classes: focal, generalised, unknown whether focal or generalised, and unclassified. Classification matters because seizure type can influence diagnosis, investigation and treatment.

First: seizure type is not the same as epilepsy type

These terms are related, but they are not interchangeable.

Seizure type describes an individual seizure.
Epilepsy type describes the broader pattern of epilepsy.
Epilepsy syndrome is a recognisable clinical pattern defined by features such as seizure types, age of onset, EEG findings, imaging, genetics and associated features.

A person can have more than one seizure type, and recognising the overall syndrome can be more informative than naming a single seizure alone.

The 2025 ILAE framework

The updated classification no longer relies on the older motor-versus-non-motor split. Instead, focal and unknown-class seizures can be described as having observable manifestations or no observable manifestations. The terminology also uses consciousness, defined using both awareness and responsiveness, rather than awareness alone.

You may still see older terms such as focal aware seizure, focal impaired awareness seizure, simple partial seizure, complex partial seizure or secondary generalisation in older records, websites or conversations. These describe concepts that have been renamed or refined over time rather than completely different conditions.

1. Focal seizures

Focal seizures arise in networks limited to one cerebral hemisphere. What the seizure looks or feels like depends on the brain networks involved and how seizure activity spreads.

Focal preserved consciousness seizure

Consciousness remains preserved. The person may experience unusual sensations, changes in vision or hearing, a sudden smell or taste, tingling, jerking, emotional changes, autonomic symptoms, déjà vu, rising abdominal sensations or other symptoms while remaining aware and responsive.

These seizures can be entirely subjective. If there is nothing obvious for another person to see, the seizure may have no observable manifestations.

Focal impaired consciousness seizure

Consciousness is impaired during the seizure. A person may appear awake but be unable to respond normally, may respond inconsistently, or may later have little or no memory of the event. Observable features can include staring, repetitive hand movements, lip smacking, chewing, wandering or other automatic behaviours, but not every seizure includes automatisms.

Focal-to-bilateral tonic-clonic seizure

A seizure begins focally and then spreads to involve both sides of the brain, producing a bilateral tonic-clonic seizure. There may be an earlier focal symptom or sign before loss of consciousness and bilateral stiffening and rhythmic jerking.

This is different from a generalised tonic-clonic seizure, which is classified as generalised from the outset.

What can happen during a focal seizure?

The 2025 classification encourages clinicians to describe seizure features in the order they occur. Possible features include sensory symptoms, autonomic changes, cognitive or emotional experiences, speech or language disturbance, automatisms, tonic or clonic movements, myoclonus, dystonia, behavioural arrest and many other manifestations.

This chronological description can carry neurological information. The first symptom is important, but later signs can also help show how seizure activity spreads through brain networks.

2. Generalised seizures

Generalised seizures rapidly involve bilaterally distributed brain networks. They are not defined simply by whether the whole body moves. Some generalised seizures cause only brief changes in consciousness or very short muscle jerks.

Absence seizures

Absence seizures typically cause a brief interruption of consciousness, often with sudden stopping of activity and reduced responsiveness. They can be subtle and may occur many times a day.

The 2025 classification includes typical absence, atypical absence, myoclonic absence, and eyelid myoclonia with or without absence. These are clinically distinct patterns and should not all be treated as interchangeable forms of staring.

Generalised tonic-clonic seizures

These involve loss of consciousness with a tonic phase of stiffening followed by a clonic phase of rhythmic jerking. Breathing, skin colour and saliva can change during the seizure, and recovery afterwards may include confusion, headache, muscle pain, exhaustion or sleep.

The 2025 classification also recognises specific patterns including myoclonic tonic-clonic seizures and absence-to-tonic-clonic seizures.

Generalised myoclonic seizures

Myoclonic seizures cause brief, shock-like muscle jerks. They may affect both arms, the shoulders or other muscle groups and can be easy to mistake for clumsiness or dropping things.

Generalised clonic seizures

Clonic seizures involve repeated rhythmic jerking without the sustained tonic stiffening that defines the tonic phase of a tonic-clonic seizure.

Generalised tonic seizures

Tonic seizures cause a sustained increase in muscle tone. The body or limbs may suddenly stiffen, sometimes causing a fall.

Generalised atonic seizures

Atonic seizures cause a sudden loss or marked reduction of muscle tone. The head may drop, an object may fall from the hand, or the person may collapse suddenly. Because falls can be abrupt, injury risk can be significant.

Generalised myoclonic-atonic seizures

These combine a myoclonic jerk with a subsequent loss of muscle tone. They are particularly associated with certain epilepsy syndromes.

Generalised epileptic spasms

Epileptic spasms are brief movements involving sudden flexion, extension or mixed flexion-extension of groups of muscles. They may occur in clusters. The classification of epileptic spasms depends on the broader electroclinical context.

Generalised negative myoclonic seizures

The 2025 ILAE classification formally recognises generalised epileptic negative myoclonus. Instead of an extra muscle jerk, there is a very brief interruption of ongoing muscle activity, which can cause a limb or held object to suddenly drop.

3. Unknown whether focal or generalised

Sometimes there is convincing evidence that an event is an epileptic seizure, but there is not enough information to determine whether it is focal or generalised. The seizure can then be classified as unknown whether focal or generalised rather than forcing it into the wrong category.

The 2025 framework includes preserved-consciousness, impaired-consciousness and bilateral tonic-clonic seizures within this class when the focal-versus-generalised origin cannot yet be established.

This classification can change later if more information becomes available from history, EEG, imaging, video-EEG or subsequent seizures.

4. Unclassified seizures

A seizure is unclassified when the available information is insufficient to place it into one of the defined seizure types. This is not the same as saying the event is not epileptic. It means the evidence does not yet support a more specific classification.

Observable does not mean more severe

One of the most important changes in the 2025 framework is the distinction between seizures with and without observable manifestations. A seizure does not need to produce visible shaking, collapse or obvious behaviour to be significant.

Some focal seizures may be experienced almost entirely internally: a sudden smell, an intense feeling of familiarity, a rising sensation, a distortion of perception, a brief language problem or another subjective change. These can still be epileptic seizures even when a witness sees very little.

Consciousness can be more complicated than “awake” or “unconscious”

The ILAE now uses consciousness as a classifier, based on both awareness and responsiveness. Someone may have their eyes open but still have impaired consciousness. Another person may remember part of an event but have been unable to respond normally.

This is why descriptions such as “they were awake” or “they did not pass out” are not enough on their own to classify a seizure.

Auras are seizures

When an aura is caused by focal epileptic activity, it is itself a focal seizure rather than merely a warning that a seizure may happen later. It may remain isolated or progress into a seizure with impaired consciousness or a focal-to-bilateral tonic-clonic seizure.

The exact symptom depends on the networks involved, which is why auras can include sensory, autonomic, emotional, cognitive and experiential phenomena.

Not every collapse or episode of shaking is epileptic

Syncope, cardiac rhythm disturbances, sleep disorders, migraine, movement disorders and functional or dissociative seizures can all produce events that resemble epilepsy. Conversely, genuine epileptic seizures can occur without dramatic movement.

Classification therefore depends on the clinical history and, where appropriate, EEG, imaging, video evidence and other investigations rather than appearance alone.

Read more: Diagnosis and Tests →

Why getting the seizure type right matters

Classification is not just terminology. Different seizure types and epilepsy syndromes may require different investigations and can respond differently to antiseizure medicines. In some epilepsies, choosing a medicine without recognising the seizure type or syndrome can worsen particular seizure types.

The aim is therefore not simply to attach a label to an event, but to use seizure classification as one part of a wider diagnosis that guides safe, appropriate treatment.

Read more: Treatment Options →

The central point

There is no single appearance of an epileptic seizure. A seizure may involve convulsions, but it may also appear as a pause, a drop, a jerk, stiffening, repetitive behaviour, a brief loss of responsiveness, an internal sensation or a change that nobody else can see.

Accurate classification comes from understanding where the seizure is likely to arise, what happens to consciousness, what signs and symptoms occur, how they unfold over time and how the event fits into the person’s broader epilepsy.

Where next?

What Is Epilepsy? →
Diagnosis and Tests →
Treatment Options →
Back to Understanding Epilepsy →

Sources

Medical note: This page is for education and awareness and is not a substitute for individual medical advice. Seizure classification should be made in clinical context and may change as more information becomes available.

Evidence checked: September 2026.