Different Types of Seizures

Seizures are caused because of abnormal electrical activity in the brain, resulting in convulsions, in which a person's body shakes continuously and uncontrollably. Seizures occur due to a number of reasons, such as fever, brain tumor, injury, electrolyte imbalance, high or low blood sugar, drug withdrawal, gastrointestinal disease, medicine and even brain injury. Older patients with a history of neurodegenerative disorders like Alzheimer's disease are more prone to have a seizure. Muscle spasms, frothing at the mouth, loss of bladder or bowel control, temporary halt in breathing and uncontrollable shaking are some of the symptoms that can occur while experiencing a seizure.

Different Types of Seizures

Seizures are often confused with epilepsy, because the symptoms look the same. However, there are two types of seizures or seizure disorders, namely epileptic seizures and non-epileptic seizures. In this article, we are focusing on the second category, i.e. non-epileptic seizure. When a person has multiple and repeated seizures with no apparent cause, it is known as epilepsy. The non-epileptic seizures are usually triggered by some physical or psychological cause. Certain mental disorders can also cause symptoms of seizure.

Symptoms of seizure vary in their severity and can last from 30 seconds to two minutes. However, if a seizure lasts for more than five minutes or if a person has them successively in breaks, or becomes unconscious during an occurrence, it is a medical emergency. In 1981, the International League Against Epilepsy (ILAE) differentiated between the types of seizures, for the purposes of prognosis and treatment. According to ILAE, seizures are mainly classified into two categories or types: focal seizures and primary generalized seizures.

Focal Seizures

Focal seizures are also called partial seizures, as they occur in just one part of the brain. Most patients experiencing a partial seizure stay alert and have a good memory of their actions. This form is further categorized into three types depending on the type of symptoms the person exhibits. The different types of seizures in this category and their subtypes are listed below.

Simple Partial Seizures: Simple partial seizures affect only one part of the brain and the symptoms may vary depending on which part of the brain is involved. Following are the different types of simple partial seizures:

• Motor Seizures: In this seizure, the person exhibits abnormal body movements, such as automatic hand movements and jerking or stiffening of body parts. These movements can spread from one side to the other side of the body. In some instances, even speech has been known to be affected.
• Sensory Seizures: This seizure affects the senses of a person. The ability to hear, taste, smell and see is greatly distorted. Some patients experience visual hallucinations and illusions.
• Autonomic Seizures: In this seizure, changes occur in the nervous system, affecting bodily movements, causing changes in the heart rate, disturbed breathing, sweating or unpleasant sensations in the head, chest or stomach.
• Psychic Seizures: This seizure causes changes in the affective domain, like the way the people feel, think and experience things. The patient will have trouble expressing himself/herself through, both spoken or written words. They feel sudden spurts of happiness, fear or depression, for no apparent reason. Some have been known to feel a sense of déja vu.

Complex Partial Seizures: When a simple partial seizure affects the temporal or frontal lobe and spreads to a larger area of the brain, it is known as complex partial seizure.

• Temporal Lobe: The seizure starts in the temporal lobe and then spreads around, affecting the awareness and alertness of the person. The symptoms feel like those of daydreaming and most patients don't recall that they have had a seizure.
• Frontal Lobe: The duration of the seizure tends to be shorter than the one started in the temporal lobe and results in pelvic thrusting and bicycling-like movements of the legs.

Secondarily Generalized Seizures: Some complex partial seizures turn into secondarily generalized seizures and occur after a partial seizure has begun. This seizure occurs when the sudden electrical activity spreads from a limited area to the entire brain. Some patients do not have any recollection of the first part of the seizure.

Primary Generalized Seizures

This type of seizure occurs when both sides of the brain are affected by the widespread electrical activity. Heredity plays an important role in these seizures. The types of seizures that fall under this category are as follows:

• Myoclonic Seizures: This seizure occurs for a very brief moment. The patient suffers jerks or twitches of a muscle or a group of muscles very rapidly, mostly on one side of the body.
• Absence Seizures: These seizures start and end abruptly and usually last for 20 seconds. The ability to respond and general awareness is impaired temporally and most patients don't even realize that they have had a seizure. During the seizure, the person may blink repetitively, roll up the eyes or just stare.
• Atypical Absence Seizures: Here the patient just stares, but is still responsive, though the responses are very slow. The seizures begin and end gradually, occurring for a duration of around 30 seconds, and are accompanied by slight jerking lip movements and eye blinking.
• Atonic Seizures: Atonic seizures are also known by the name 'akinetic', which means without movement. This seizure is characterized by loss of muscle strength, but there is no loss of consciousness. As a result, the person's eyelids may droop and he may fall down or drop things.
• Tonic Seizures: These occur mostly during sleep and result in sudden stiffening of the body, arms, or legs. These seizures usually last for 20 seconds and affect most of the brain.
• Clonic Seizures: The word clonic is taken from 'clonus', which means rapidly alternating contraction and relaxation of a muscle. This seizure occurs rarely and the repeated jerking movements can't be restrained or repositioned.
• Tonic-Clonic Seizures: As the name implies, this seizure has the characteristics of both tonic and clonic seizure. The tonic phase precedes the clonic phase; first the body stiffens and the person may fall to the ground and in the process, may bite his own tongue or lips causing blood to come out from the mouth, along with froth. Then the clonic phase brings with it rapid and constant jerky body movements. This is the type that most people relate, when the word seizure is used.

A person may suffer from more than one kind of seizures and one that lasts for 30 seconds or more, and is repetitive requires medical attention. Life can become difficult for the family and person experiencing seizures. Awareness and readily available medical help can go a long way in helping them cope with the seizure disorder.