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.
Focal Onset Seizures
Focal seizures occur when just one part of the brain has abnormal electrical activity. About 60 percent of people with epilepsy have focal seizures. These seizures are usually given a name based on the area of the brain in which they take place. For example, someone might be diagnosed with focal frontal lobe seizures.
Focal seizures are further separated into 2 categories:
Sometimes, during a focal seizure, a person will perform more complicated actions, without meaning to do them. Patients may also continue to do the activities they started before the seizure began, such as washing dishes in a repetitive, unproductive fashion. These seizures usually last just a few seconds.
Some people with focal seizures, especially complex focal seizures, may experience auras – unusual sensations that warn of an impending seizure. These auras are actually simple focal seizures in which the person stays conscious. How these symptoms appear and how they progress tend to be stereotyped, which means they are similar every time.
The symptoms of focal seizures can easily be confused with other disorders. For instance, the dreamlike quality of a complex focal seizure may be wrongly diagnosed as migraine headaches, which also may cause a dreamlike state. The strange behavior and sensations caused by focal seizures also can be mistaken for symptoms of narcolepsy (a sleep disorder), fainting or even mental illness. It may take evaluation by an experienced physician to tell the difference between epilepsy and other disorders.
Some focal seizures secondarily generalize. This means that the seizure in one place of the brain but as the seizure proceeds, it ultimately involves both sides of the brain resulting in a generalized seizure.
Generalized seizures are caused by abnormal nerve cell activity that starts on both sides of the brain. These seizures may cause loss of consciousness. Some generalized seizures are “convulsive” meaning they have generalized motor movements. Other generalized seizures are “non-convulsive” meaning that the seizure occurs without generalized motor movements.
Types of generalized seizures:
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