The Ictal Phase of a Seizure

The Most Detectable Part of a Seizure

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The ictal phase is the most symptomatic and recognizable aspect of a seizure. While it may be the shortest seizure phase—lasting only a few seconds—the ictal phase of a seizure is often associated with involuntary movements or a decreased level of awareness.

There are a number of seizure types, and they are typically identified based on the effects that occur during the ictal phase. Generally, during this phase, there are changes in brainwave activity that can be detected with an electroencephalogram (EEG).

Prevention is the key to seizure management, and anti-epilepsy medication is typically used on a daily schedule to reduce or inhibit the occurrence of seizures. The ictal phase of a seizure usually resolves on its own without medical intervention. But sometimes, a condition called status epilepticus may occur, in which the ictal phase of a seizure is prolonged. In these situations, fast-acting anti-epilepsy medication is required to end the episode.

A seizure ictal phase
The ictal phase of a seizure may show EEG changes.

Getty Images / James Holmes / Science Photo Library


You can experience a number of symptoms during the ictal phase of a seizure. You may not be aware of what is happening while you are experiencing this phase.

Symptoms that can occur during the ictal phase of a seizure may include:

  • Rhythmic shaking and jerking of one arm or leg
  • Shaking or jerking of the whole body
  • Stiffness of part of the body or the whole body
  • Twitching of your face
  • Tongue smacking
  • Eye blinking
  • Grunting noises
  • Staring into space
  • Sudden falling
  • Dropping an object
  • Loss of bowel or bladder control

You can experience any combination of these symptoms during the ictal phase of a seizure, and you might not be able to remember the episode.

Seizure Types

Seizures can be convulsive or nonconvulsive. A convulsive seizure involves involuntary (not on purpose) movements during the ictal phase, and a nonconvulsive seizure involves impairment of consciousness without involuntary physical movements during this phase.

A generalized seizure involves a complete lack of awareness during the ictal phase, while a partial seizure involves some impairment of awareness but does not cause complete unawareness.

Pre-ictal and Post-ictal Phases

Sometimes, the ictal phase of a seizure is preceded by a seizure aura, which is a brief pre-ictal phase that occurs immediately before a seizure. An aura can involve unusual sensations or movements that are not exactly the same as the experiences that occur during the ictal phase.

After the ictal phase of a seizure, a post-ictal phase can occur. This phase is characterized by tiredness, sleeping, and sometimes muscle weakness (usually on one side of the body).

You can experience one, both, or neither of these phases in addition to the ictal phase of a seizure.


The ictal phase of a seizure is caused by erratic brain activity. A predisposition to seizures can result from a brain injury due to low oxygen, a birth defect, a stroke, a brain tumor, or an abnormal blood vessel.

Recurrent epileptic seizures are called epilepsy. You can experience an ictal event if you have epilepsy and sometimes even if you don’t have epilepsy. Certain triggers can precipitate a seizure, especially if you have epilepsy.

Seizure triggers include:

  • Alcohol consumption
  • Alcohol withdrawal
  • Recreational drugs
  • A very high fever
  • A brain infection
  • Disrupted electrolyte levels (such as sodium, potassium, and calcium)
  • Sleep deprivation
  • Severe nutritional deficits
  • Kidney or liver disease
  • Dehydration
  • Major infections or sepsis (blood infection)
  • Head trauma

If you take anti-epilepsy medications for seizure prevention, skipping your medications can trigger a seizure.

How the Brain Produces the Ictal Seizure Phase 

The middle of a seizure is often called the ictal phase. It's the period of time from the first symptoms to the end of the seizure activity. This correlates with the electrical seizure activity in the brain, which can be seen in an electroencephalogram (EEG).

It takes several seconds for the brain stimulation of a seizure to slow down. The involuntary physical movements of a seizure tend to repeat in a rapid and rhythmic pattern until the brain stimulation ceases.

During a seizure aura and during the post-ictal phase, the brain is also subjected to unusual stimulation. But the brain stimulation experienced during the non-ictal phases of a seizure is typically not strong enough to produce the symptoms that are characteristic of the ictal phase.

Testing and Diagnosis 

The ictal phase of a seizure is typically recognized by the symptoms. However, if there is any uncertainty regarding the cause, diagnostic tests are often used.

Electroencephalogram (EEG) 

An EEG is a noninvasive brain wave test. It detects electrical activity in the brain. During an EEG, metal plates (approximately the size of coins) are placed superficially on the scalp. The metal plates detect the brain’s electrical activity, and a computer produces a corresponding brain wave pattern.

Normally, the brain displays a consistent electrical rhythm. During the ictal phase of a seizure, brain waves are somewhat erratic and disorganized. This erratic activity affects the whole brain during the ictal phase of a generalized seizure, and it affects a localized region of the brain during the ictal phase of a partial seizure.

It is difficult to schedule an EEG at the same exact time as the ictal phase of a seizure. In some instances, a sleep-deprived EEG can more effectively detect the ictal phase of a seizure. This is because sleep deprivation often triggers an ictal event (especially when a person is predisposed to seizures due to epilepsy or another reason).

Brain Imaging Studies 

Brain imaging studies, such as computerized tomography (CT) and magnetic resonance imaging (MRI), can provide your medical team with a picture of the structure of your brain. While these tests do not identify seizures, they can help identify other problems such as a stroke or multiple sclerosis, brain tumor, or other structural lesions of the brain.

Functional MRI (fMRI) may show changes that correlate with EEG changes during the ictal phase of a seizure.


In general, the ictal phase of a seizure usually resolves on its own without immediate treatment. However, sometimes treatment is needed if this phase is prolonged or particularly severe. 

Status epilepticus is a condition in which the ictal phase of a seizure does not stop on its own. This is a medical emergency that requires treatment. During the ictal phase of a seizure, you may need to take your medication by injection because it can be dangerous to swallow a pill (or you may be unable to swallow).

The most commonly used medications to manage status epilepticus include:

  • Dilantin (phenytoin)
  • Phenobarbital
  • Ativan (lorazepam)
  • Valium, Diastat, (diazepam)
5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Heidi Moawad, MD
Heidi Moawad is a neurologist and expert in the field of brain health and neurological disorders. Dr. Moawad regularly writes and edits health and career content for medical books and publications.