Epilepsy: What are the different kinds of seizures?

by Placerville Newswire / May 25, 2018 / comments

[Cris Alarcon]

I was 50-years-old when I was hospitalized for my first major seizure in December of 2015.  I had been very healthy up to that time, or so I thought!  After being diagnosed with epilepsy I started on a journey to understand who this stranger is in my head. This is a multi-part story starting with "What are the epilepsies?"  The epilepsies are chronic neurological disorders in which clusters of nerve cells, or neurons, in the brain sometimes signal abnormally and cause seizures


What are the different kinds of seizures?

Seizures are divided into two major categories – focal seizures and generalized seizures. However, there are many different types of seizures in each of these categories. In fact, doctors have described more than 30 different types of seizures.

Focal Seizures

Focal seizures originate in just one part of the brain. About 60 percent of people with epilepsy have focal seizures. These seizures are frequently described by the area of the brain in which they originate. Many people are diagnosed with focal frontal lobe or medial temporal lobe seizures.

In some focal seizures, the person remains conscious but may experience motor, sensory, or psychic feelings (for example, intense dejà vu or memories) or sensations that can take many forms. The person may experience sudden and unexplainable feelings of joy, anger, sadness, or nausea. He or she also may hear, smell, taste, see, or feel things that are not real and may have movements of just one part of the body, for example, just one hand.

In other focal seizures, the person has a change in consciousness, which can produce a dreamlike experience. The person may display strange, repetitious behaviors such as blinks, twitches, mouth movements (often like chewing or swallowing, or even walking in a circle). These repetitious movements are called automatisms. More complicated actions, which may seem purposeful, can also occur involuntarily. Individuals may also continue activities they started before the seizure began, such as washing dishes in a repetitive, unproductive fashion. These seizures usually last just a minute or two.

Some people with focal seizures may experience auras – unusual sensations that warn of an impending seizure. Auras are usually focal seizures without interruption of awareness ( e.g., dejà vu, or an unusual abdominal sensation) but some people experience a true warning before an actual seizure. An individual’s symptoms, and the progression of those symptoms, tend to be similar every time. Other people with epilepsy report experiencing a prodrome, a feeling that a seizure is imminent lasting hours or days.

The symptoms of focal seizures can easily be confused with other disorders. The strange behavior and sensations caused by focal seizures also can be mistaken for symptoms of narcolepsy, fainting, or even mental illness. Several tests and careful monitoring may be needed to make the distinction between epilepsy and these other disorders.

Generalized Seizures

Generalized seizures are a result of abnormal neuronal activity that rapidly emerges on both sides of the brain. These seizures may cause loss of consciousness, falls, or a muscle’s massive contractions. The many kinds of generalized seizures include:

  • -- Absence seizures may cause the person to appear to be staring into space with or without slight twitching of the muscles.
  • -- Tonic seizures cause stiffening of muscles of the body, generally those in the back, legs, and arms.
  • -- Clonic seizures cause repeated jerking movements of muscles on both sides of the body.
  • -- Myoclonic seizures cause jerks or twitches of the upper body, arms, or legs.
  • -- Atonic seizures cause a loss of normal muscle tone, which often leads the affected person to fall down or drop the head involuntarily.
  • -- Tonic-clonic seizures cause a combination of symptoms, including stiffening of the body and repeated jerks of the arms and/or legs as well as loss of consciousness.
  • -- Secondary generalized seizures.

 

Not all seizures can be easily defined as either focal or generalized. Some people have seizures that begin as focal seizures but then spread to the entire brain. Other people may have both types of seizures but with no clear pattern.

Some people recover immediately after a seizure, while others may take minutes to hours to feel as they did before the seizure. During this time, they may feel tired, sleepy, weak, or confused. Following focal seizures or seizures that started from a focus, there may be local symptoms related to the function of that focus. Certain characteristics of the post-seizure (or post-ictal) state may help locate the region of the brain where the seizure occurred. A classic example is called Todd’s paralysis, a temporary weakness in the part of the body that was affected depending on where in the brain the focal seizure occurred. If the focus is in the temporal lobe, post-ictal symptoms may include language or behavioral disturbances, even psychosis. After a seizure, some people may experience headache or pain in muscles that contracted.


Part 3: What are the different kinds of epilepsy?