The main types of seizures are generalized and focal ones. Depending on the area of the brain that is affected, the presence of one type or another will be determined.
A seizure is based on an abnormal electrical discharge from the brain that can cause fainting, loss of consciousness, and the realization of involuntary and uncontrolled motor movements (spasms).
However, not all seizures are the same, since there are several types of seizures depending on the brain involvement that occurs.
The term seizure or seizure attack refers to sudden or sudden brain dysfunction that causes the person to collapse, have seizures, or present other behavioral abnormalities temporarily.
From a medical point of view, the seizure is simply a transitory symptom that is characterized by neuronal activity in the brain that leads to peculiar physical findings such as contraction and repeated and trembling distension of one or more abrupt muscles.
Also, seizures can cause alterations in the mental state of the person and psychiatric disorders such as dejà vu or jamais vu.
Today it is known that most seizures are caused by electric shocks that occur in the brain or by fading, that is, by a reduction in cerebral blood supply.
Types of seizures and their characteristics
In general, there are two major types of seizures; however, we will see how many different subtypes can be seen in each type of seizure.
These types of seizures are those that are caused by abnormal activity of neurons on both sides of the brain. T al and as the name implies, in generalized seizures, the entire brain is affected by abnormal electric shocks.
By affecting the entire brain, it is considered that these types of seizures have a greater severity than those that are not generalized. Likewise, the famous symptoms such as fainting, loss of consciousness, or the presence of muscle spasms are usually prototypical of this type of seizures.
When we talk about the generalized seizure, we are most likely doing it on that most popular type of seizure. However, despite the fact that this type of crisis is the one that produces the most frequent muscle spasms, not all types of generalized seizures do.
And it is that among the generalized seizures, we find different subtypes of crisis, each of them with certain characteristics.
In fact, among these types of seizures we can find «convulsive» crises, that is to say with the presence of involuntary and generalized motor movements, and «non-convulsive» crises, in which this type of muscle spasms does not occur.
Crisis with no seizure
This type of crisis is characterized by the absence of seizure, that is, when the person suffers from this type of crisis does not manifest the typical muscle spasms. This type of crisis belongs to generalized seizures, so it is characterized by the presence of abnormal activity in neurons on both sides of the brain.
Normally the condition of this type of crisis, despite not involving the presence of muscle spasms and being visually less aggressive, is usually serious. The person who suffers from it may appear to be looking into space or have slight tremors in their muscles.
However, they are considered as “small evil” convulsions, and the person who suffers from it keeps their eyes fixed for a few seconds and then returns to full function.
After suffering this crisis, the individual does not remember what happened during the seizure. However, they do not usually produce the typical post-natal period (after the seizure) that we will see that they do appear in the vast majority of other types of crises.
In this type of generalized crisis, there are spasms or muscular contractions. It is mainly characterized by the presence of rapid jerks of body muscles, especially those of the arms and legs, and loss of consciousness.
Myoclonic seizures may be caused by different pathologies.
A cause of myoclonic crisis classifies the seizure as benign or non-epileptic and produces very mild shaking, similar to those we have when we sleep.
The other causes of this type of crisis are epileptic. Among them, we can find one that is exclusive to childhood, benign myoclonic epilepsy. It consists of a strange disorder, which is present in a few cases and begins between 4 and two years of life.
The other two causes of myoclonic seizure are severe myoclonic epilepsy, which consists of a disorder that causes chronic and progressive brain damage, and Lenox-Glastaut syndrome, a severe neurological disorder that is associated with the absence of spike waves in the EEG and mental retardation.
These types of seizures cause extreme stiffness of the muscles of the body, usually the back, legs, and arms.
Like the rest, they are explained by abnormal electrical discharges in the brain and cause fainting and loss of consciousness in most cases.
Like the previous one, there are muscular alterations, but they are differentiated by the presence of repeated jerky movements in the muscles of both sides of the body instead of extreme muscular stiffness.
This type of crisis could be associated with the popularly known seizure in which the person “convulses” through sudden muscle movements and constant spasms.
This type of crisis presents a mixture of symptoms of tonic seizures and clonic seizures. The person may have stiffness in the body, repeated pulling on the limbs and total loss of consciousness.
This type of crisis is considered as the “great evil” seizures and is interpreted as the most serious of all types of generalized seizures.
The last type of generalized seizures is characterized by a total loss of muscle tone.
The person affected by this type of seizure will fall or drop his head involuntarily and will collapse when losing his muscle tone in virtually the entire body.
– Focal onset crisis
Unlike generalized seizures, these types of seizures are characterized by affecting only a particular region of the brain.
Abnormal electrical discharges that characterize seizures, in this case, only affects a small part of the brain, so the rest of neuronal structures are not affected by the seizure.
This type of crisis is considered less serious than the previous ones but much more prevalent in society. In fact, it is estimated that about 60% of people with epilepsy suffer from focal seizures rather than generalized seizures.
Likewise, this type of seizure does not usually affect the person’s conscience, so when an individual suffers from a focal crisis, despite being able to lose their state of consciousness slightly, they will rarely pass out or be totally unconscious.
Likewise, the typical muscular symptoms through spasms and rapid and aggressive shaking in different regions of the body, are also not seen in focal onset seizures.
Focal seizures refer to this type of crisis that can be virtually asymptomatic in some cases, and that is much less noticeable and impactful than generalized crises.
Usually, although seizures can be categorized according to the brain region that affects them, they are subdivided into two main categories:
Simple focal crisis
Before this type of seizure, the person remains conscious and does not faint or lose consciousness at any time. However, you may experience unusual, unusual feelings, sensations, or experiences.
In the presence of the crisis, that is, abnormal electrical activity in a specific region of the brain, the individual, may have sudden and inexplicable feelings of joy, anger, or sadness.
Likewise, you may also have symptoms such as nausea or vomiting and have strange sensory experiences such as hearing, smelling, seeing, or feeling things that are not real.
Complex Focal Crises
This type of seizure differs from the previous one, mainly by the affectation of consciousness. M hile, in simple crisis, are unconscious; in this type of seizure, the individual has a slight loss of consciousness.
It is usual for the person suffering from a complex crisis to report a dream or strange experience, of which he does not remember anything clearly.
During the crisis, the person can perform strange behaviors such as repetitive movements of the eyelids, motor tics, rare movements with the mouth or even alterations in the march, but will not present the muscle spasms typical of the generalized crises.