A Guide To The Postictal Phase Of Seizures

Ictal comes from the Latin word Ictus, which means ‘to strike’ but commonly refers to seizure in English. Therefore, postictal refers to the period after the seizure until you return to baseline. 

The sophisticated definition is “a temporary brain condition following seizures (a) manifesting neurological deficits and/or psychiatric symptoms, (b) often accompanied by EEG slowing or suppression, (c) lasting minutes to days.’’ 

The brain and seizures

A seizure occurs when there is excessive electrical activity in the brain. The electrical disturbance can be widespread within the brain or restricted to one area. These are called generalized or focal seizures, respectively. 

Generalized seizures can be:

• Tonic (increased muscle tone)

• Atonic (decreased muscle tone)

• Clonic (convulsions)

• Tonic-clonic (jerking motion)

• Myotonic (short muscle twitches)

• Absence (‘spaced out’ feeling)

The presentation of focal seizures depends on which area of the brain is affected. In anatomy, the brain is separated into four lobes, each having certain functions. 

• Frontal lobe: motor function and executive function

• Parietal lobe: integration of sensory information

• Temporal lobe: memory, hearing, smell, language, and emotion

• Occipital lobe: processing visual information 

Because the brain's structure is largely linked to its function, symptoms are highly suggestive of their origin. For example, focal seizures originating in the occipital lobe may trigger temporary blindness after termination.

It is also important to know that certain functions can be localized to one side of the brain. The left side of our brain is often dominant and contains functions such as language.

What happens after the seizure?

After the seizure is finished, most people will experience the postictal phase. A study¹ published in the 2016 Neurology journal investigated the frequency of the postictal phase affecting people with seizures in nearly 2,000 participants. 

It found that 72% of participants with epilepsy and 50% with a non-epileptic seizure (e.g., first time having one) experienced some behavioral impairment. 

The most common symptoms are unresponsiveness, headaches, migraines, and psychosis. A systematic review of 45 studies reported the respective frequencies being 96%, 33%, 16%, and 4%. For most people, this lasts between five and thirty minutes, but some symptoms (especially mood) can last for days.

Scientifically, this phase is typically characterized by reduced electrical activity in the affected part of the brain as a way to recover. 

Why does it occur?

Seizure activity is thought to stop due to depleted resources (e.g., energy and substrates). The mechanism is not completely understood, but potentially multiple factors are involved. The overall picture is inhibition or a ‘quieting of the system.’

One hypothesis is that the active dampening of the affected area for some time is a way of recovering. This is known as active inhibition.

If you want to explore potential mechanisms further, click this link.²

What are the signs and symptoms of the postictal phase?

Signs and symptoms vary between individuals and depend on many factors, including age, type and severity of the seizure, and underlying brain function. Many processes can be affected, including movement, memory, and speech.

1. Changes in consciousness

As mentioned, 96% of people with epilepsy report being less responsive after a seizure. This could be an inability to understand your surroundings properly and/or communicate with others. You might find that you are confused, sleepy, and drowsy. 

2. Changes in cognition

It is not uncommon for people not to realize that they have had a seizure, and someone else will have to tell them what has happened. One source³ hypothesizes that seizures will often occur in the parts of the brain responsible for memory, ultimately hijacking it. 

Other cognitive changes include delirium. Delirium can be considered acute brain failure. You might recognize delirium as a hyper-arousal state with hallucinations and increased activity, but the hypoactive state is more common days after the seizure.

3. Changes in motor control

If you have a seizure that affects the parietal lobe and motor control, hence, it may affect how you move afterward. One example is Todd’s paresis,⁴ which was first described in 1849. This is weakness or paralysis of part or all of the body in the postictal phase. 

It typically presents as weakness in one limb or half of the body. One study⁵ reports that 13% of their participants with atonic seizures experienced this condition.

It is important to note that the motor pathway crosses before entering the body, i.e., it is contralateral. Therefore, the right side of the brain controls the left side of the body and vice versa. As a result, weakness on one side of the brain will indicate that the seizure occurred in the other half. 

4. Changes in mood

You might feel low and anxious about the future in the days after a seizure. One study investigated 100 people with focal epilepsy and reported that 18% experienced symptoms associated with depression, including helplessness and self-worthlessness. 

Furthermore, you might become fearful or scared of an event in the future.

5. Changes in visual and auditory perception

Visual impairments, such as blindness, have been reported in seizures that implicate the occipital lobe. Auditory impairments can also occur in temporal lobe seizures.

If the left temporal lobe is affected, you might experience problems with language, e.g., listening, comprehension, and speaking. It is reported that 38% of people will have some difficulty with language postictally.

If your right temporal lobe is affected, you might have problems with visual stimuli, e.g., recognizing people. 

6. Headaches

This is very common. One study reported that approximately 66% of participants experienced postictal headaches of various intensities and duration. 

7. Psychiatric symptoms

This is a rare consequence of seizures. One study reported that 2% and 4% of people with epilepsy suffer from psychosis postictally, and this can take weeks to recover from. 

8. Social and economic implications

Being aware that you are prone to having seizures can be scary and embarrassing. You might start to withdraw from social events because you do not want to have a seizure in the 'wrong' place. 

The postictal symptoms afterward might keep you at home, and, as mentioned, you might feel depressed and anxious about another one occurring. 

People with severe and prolonged postictal symptoms can have employment difficulties. Employers may be more reluctant to hire an individual who requires sick leave frequently.

When do these symptoms stop?

Symptoms can occur at different rates (due to various factors and their interaction which is still unknown). The postictal phase can be separated into:

• T1: seconds/minutes

• T2: hours

• T3: days/weeks

Unresponsiveness and headaches are grouped into T1. Motor weakness (T2) typically lasts longer, and some people can have changes in mood (T3), energy (T3), and cognition (T3) over days. 

What is the primary concern for a person in the postictal phase of a seizure?

For many reasons, it is very important to be aware of the postictal phase. Primarily, it can be used to indicate when to return to a normal activity level without any risk. This is irrespective of whether this is your first seizure or whether you have had seizures in the past.

What are other reasons?

If this is your first seizure, the postictal symptoms can be used to determine which part of the brain is affected. The brain’s structure and function are closely linked, so symptoms can suggest what is going on. 

Many symptoms are specific to certain types of seizures. For example, you might be able to communicate effectively after your seizure if it was focal and restricted to your non-dominant hemisphere. When meeting with your doctor, it is important to mention these postictal symptoms. 

If you have had seizures in the past and are now experiencing different types of symptoms and/or they are worse than normal, further investigation is warranted. 

For example, new muscle weakness in one arm could suggest vascular damage that needs to be properly investigated. Once the alternative causes have been ruled out, supportive measures can be started. This includes hydration, relaxation, etc.

The lowdown

The postictal phase is the period after a seizure before you return to your baseline. It presents in everyone differently, but the most commonly reported symptoms include unresponsiveness, headaches, and confusion. Typically, they occur minutes to hours after the seizure, but changes in mood and energy levels can persist for days. 

Awareness of the postictal phase is important because it will allow you to recognize when it is safe to return to normalcy. Any changes and/or worsening of symptoms need to be addressed to rule out any further causes.