A Series of Exciting Events

Posted by Donovan Cronkhite on November 17, 2022 in Cognition, consciousness, depression, Education, Emotions, Executive function, Memory, Mental Illness, Mood, Neurological Disorders, Neuroscience, NeuWrite, San Diego, Teaching | Leave a comment

Have you ever wondered what it is like to have a seizure? Well, I have epilepsy, and let me tell you: so do I. That is because there are many different types of seizures and of epilepsy, and some—like mine—involve a loss of consciousness, as well as memory deficits.

What all seizures have in common, however, is that they are a result of the overexcitation of neurons, the cells that serve as the brain’s fundamental units. Furthermore, what all forms of epilepsy have in common is that they are seizure disorders, meaning to be considered epileptic, a patient must have more than one seizure (recurring), and the seizures must be unpredictable, or without an obvious cause (e.g. electrocution or a drug overdose). Besides that, any two seizures could be completely different; we will discuss the potential symptoms of a seizure later on. Hence, physicians and neuroscientists have recognized seizures as composed of three phases, and a person’s behaviors in these different phases vary depending on the type of epilepsy, type of seizure, and location of the seizure in the brain. 

A seizure up close

Neurologically, there are three phases of a seizure, and they always follow the same pattern: preictal, ictal, and postictal. In the preictal, or aura, phase of a seizure, an individual may experience weird sensations in their body, such as deja vu, jamais vu, upset stomach, and various others. Individuals with epilepsy may not always notice the aura phase of a seizure (like me, who is just learning that I might have been having seizure auras for years.) The ictal phase is what is generally considered the seizure: in this phase, large populations of neurons send electrical signals to each other, resulting in over-excitation of the brain. Although the electrical activity in the preictal phase and the ictal phase is very similar, physicians can use certain diagnostic techniques to distinguish the two. A common tool used to identify the preictal stage of a seizure is an electroencephalogram (EEG), a device that records general electrical activity in your brain using electrodes placed on your scalp. Sophisticated algorithms can distinguish this electrical activity as preictal or ictal.

Not all seizures look the same, however. In motor seizures, which is what is generally thought of when one hears seizure, the ictal phase consists of jerking convulsions, which are uncontrollable tensing and relaxing of the muscles; this also usually results in loss of consciousness—hence why I do not know what a seizure is like. However, there are non-motor seizures, and in these, the ictal phase can have a variety of symptoms, as I alluded to earlier, such as strange sensations in the body. While the ictal phase can be the most dangerous to an individual’s physical health, a seizure’s ictal phase usually only lasts a few seconds to a few minutes. When the ictal phase of a seizure lasts longer than 5 minutes, the patient has gone into status epilepticus, which can result in permanent brain damage, or even death (1). Therefore, if you know someone who has been having a seizure for more than 5 minutes, please contact emergency services. After the ictal phase has passed, the seizure is not officially over. Now, the patient enters the postictal stage, or the recovery stage. 

The postictal stage is a little harder to define, because the end of the ictal phase is also hard to define, for most seizures (2). This is because convulsive seizures are the only ones with a distinguishable beginning and end. However, there are several different types of seizures, and convulsive seizures only make up a fraction of epileptic seizures. Although they are the most frequent type, tonic-clonic seizures only accounted for 23% of all seizures in an epidemiological survey of 1,220 patients (3). Considering that determining a patient’s baseline is also ambiguous, the end of the postictal state can be hard to define. As well, there is no data to indicate that the postictal state occurs in a large number of patients with epilepsy. 

The postictal state

A clear way to define the postictal state is by looking at the physiology of the brain following the ictal phase. Proposed mechanisms in the brain that terminate the ictal phase of a seizure include exhaustion of overexcited neurons, depletion of neurotransmitters responsible for excitation, increased neuronal inhibition (thus counteracting overexcitation), and actions that other regions of the brain perform to limit a seizure’s excitatory activity (2). These mechanisms, among others, lead researchers to believe that the primary cause of the postictal state and its side effects is neuron exhaustion and over-inhibition, effectively rendering neurons unable to continue to send their messages to their neighbors. 

Another way to determine the boundary between ictal and postictal is by using neuroimaging techniques, such as an electroencephalogram (EEG), a positron emission tomography (PET) scan, or magnetic resonance imaging (MRI) (2). These various techniques can do at least one of the following: measure the rate and/or location of the seizure (abrupt end of ictal phase versus gradual termination; seizure ends in all locations at once versus terminating at various locations at different times), study the changes in neurotransmitters and their receptors, and study the blood flow in the brain during the postictal state.

For anyone in the postictal state, common neurological functions that are affected include speech, motor, and memory. However, symptoms can vary depending on what region(s) of the brain were affected by the ictal state of the seizure. For instance, those who suffer the ictal state of a seizure in the temporal lobe of their brain can have memory deficits. Other symptoms can include motor weakness, coughing, spitting, hypersalivation, nose-wiping, psychosis, and mania (4; 5). Depression is also a symptom seen in the postictal state, as well as anxiety. How long these various symptoms and the postictal state last overall depends on how the termination of the ictal phase occurred. The good thing, however, is that these symptoms are usually not severe, and medical attention is generally not required. Rather, the individual just needs to be supported and monitored.

It depends

So, returning to the original question: what do you think a seizure is like now? Have I answered the question? Honestly, it probably isn’t a satisfactory answer, but you should realize now the correct answer is: it depends. It depends on the region of the brain affected. It depends on the severity of the seizure. It depends on the type of seizure. But most importantly, to show compassion to the epilepsy community, we should all recognize that it depends on who the person is.

References

1 ) https://www.hopkinsmedicine.org/health/conditions-and-diseases/status-epilepticus#:~:text=A%20seizure%20that%20lasts%20longer,permanent%20brain%20damage%20or%20death.

2 ) https://www.statpearls.com/ArticleLibrary/viewarticle/28844

3 ) https://pubmed.ncbi.nlm.nih.gov/3123210/

4 ) https://epilepsyfoundation.org.au/understanding-epilepsy/seizures/seizure-phases/

5 ) https://onlinelibrary.wiley.com/doi/full/10.1111/epi.16519