What Is a Postictal Phase?

After a person experiences a seizure, he or she enters an altered state of consciousness called the postictal phase, which often lasts for 5-30 minutes. The postictal phase may also be longer if an individual has more severe seizures.

This phase is characterized by disorienting symptoms along with drowsiness, headache, nausea, migraine, or hypertension. Other memory defects or amnesia may also occur after this phase.

During this phase, a person’s brain recovers from the trauma caused by the seizure. Before the postictal phase, other phases of a seizure happen:

• Preictal or prodrome -  the time before a seizure happens

• Interictal Phase - the time between seizures

• Ictal Phase - the actual seizure

Signs and Symptoms of the Postictal Phase 

After a seizure, feelings of physical and mental exhaustion are common. Most patients often complain of cognitive problems following a seizure. They include decreased interactive or verbal skills, poor concentration and attention, and poor short-term memory. These symptoms are often seen in the postictal phase.

When it comes to people with epilepsy, one of their main complaints is postictal migraines, which can be due to a number of causes. One cause may be a high intracranial pressure from postictal cerebral edema. In some cases, people may not be aware that they had a seizure, and a migraine after having one is their only clue.

Another common symptom experienced after a seizure is depression, which often manifests in people who have never experienced a seizure before. Anxiety may also be experienced by those who had a different type of seizure from their previous ones.

Other less common symptoms that are associated with the postictal phase include:

• Todd's Paralysis (TP) – This is a neurological condition that causes temporary paralysis after a seizure. The paralysis may be complete or partial and usually occurs on one side of the body. It often completely subsides within 48 hours. This condition may also affect a person’s vision or speech.

• Loss of Motor Function – This symptom is the most common, and can be accompanied by weakness to complete paralysis with temporary deafness, blindness, or numbness.

• Postictal Psychosis (PIP) – This is a serious complication that occurs after having a cluster of seizures. The condition is characterized by aggression, delusions, affective change, paranoia, and auditory and visual hallucinations. PIP is treated using standard antipsychotic drugs, and stops when seizures are no longer experienced.

• Postictal Bliss (PB) – This occurrence has been described as a blissful feeling that is associated with the development of amnesia.

Some of these symptoms tend to always arise within a few hours to a couple of days after a having seizure. A lack of responsiveness and confusion are quite common after a seizure, so if a patient does not show these postictal symptoms, it may indicate that the event may be something else and not an actual seizure. It may be due to psychogenic factors or related to syncope or “passing out.”

When healthcare providers determine the focus of the seizure, symptoms of the postictal phase can also be useful. They include:

• Decreased short-term verbal memory -  A seizure in the dominant hemisphere.

• Decreased visual memory - Seizures in the non-dominant hemisphere.

• Unable to read - Seizures in the language areas of the speech-dominant hemisphere

• Postictal Nose Wiping - The onset of the seizure is often on the same side of the hand used for wiping the nose. This symptom is often observed in people with temporal lobe epilepsy (TLE).

What is the value of an EEG in the postictal phase?

An electroencephalogram or EEG often shows the brain's slowing activity, particularly on the area of the brain, where the seizures originated. However, a slowing brain activity may sometimes show in both ictal and postictal phases. 

Moreover, the brain wave changes on an EEG are not always associated with the behavioral changes seen in patients. For this reason, some doctors focus more on the description of a person's behavior along with any changes in the EEG that occurs during or after a seizure. 

Mechanism

The neurons may become exhausted after a seizure, but without a reduction in their ability to carry an action potential. Neurons normally fire when they are stimulated, even after status epilepticus. The following are the hypotheses that could cause the symptoms associated with the postictal phase:

Depletion of Neurotransmitters

To propagate a signal to the next neuron, the neurotransmitters should be in the axon terminal and exocytosed into the synaptic cleft.

It may be possible that due to an extensive firing during a seizure, neurotransmitters could be rapidly used up than the synthesis of new ones in the cell for transportation to the axon. However, there is still no direct evidence of neurons being depleted after having seizures. 

Receptor Concentration Changes

In studies that use electroshock to stimulate seizure in rats, seizures were followed by slow waves on an EEG and unconsciousness, which are signs of postictal catalepsy. However, naloxone, a drug that blocks the effects of opioid, instantly reverses this state. It provides evidence that during seizures, there is an increased concentration of opiate receptors, which may be partially responsible for postictal symptoms in humans. When naloxone is given in-between seizures, an increased EEG activity has been observed by researchers, suggesting opioid receptor upregulation. 

Active Inhibition

It has been observed that with the postictal phase, opioid peptides are involved. It may be involved in terminating seizures. The postictal refractory period is an evidence of this active inhibition, in which weeks or even months after the seizures, could not be induced.

After successfully ending the high activity of neurons, certain changes such as changes in ion channels, signal receptors could have a residual effect for a short time, and after the seizure has ended, they would inhibit the normal firing.

Cerebral Blood Flow Changes

Sometimes, cerebral flow with respect to metabolism is not proportional after a seizure. It is possible that poor autoregulation after a seizure would occur due to changes in blood flow, and it could be possible that this could be one of the factors involved in stopping a seizure. Although in animal models, differing results have been obtained.

More than one theory may interact or contribute to the symptoms experienced during the postictal phase.