Epilepsy Neurology / Neuroscience

What are simple partial seizures?

A simple partial seizure takes place on one side of the brain. Usually, people experiencing a simple partial seizure do not lose consciousness or awareness.

Simple partial seizures are a seizure type where one side of the brain is initially affected. Sometimes the seizure activity will remain on this side, while other times the seizure activity will spread and become partial complex or secondarily generalized in type.

Doctors may also call simple partial seizures “focal aware seizures” or “simple focal seizures.”

If a person experiences repeated simple partial seizures, a doctor might diagnose them with epilepsy, which is continued seizures. An estimated 2 to 12 percent of all children with epilepsy experience simple partial seizures.

Causes

Model of brain with stethoscope to demonstrate simple partial seizures.
There may be many potential causes for simple partial seizures, including traumatic brain injuries and diabetes.

A seizure occurs when a person experiences a disturbance in their brain’s normal activity. The brain communicates via electric “signals,” so when these signals are disrupted, a person can have a seizure.

Simple partial seizures occur in people who have an electrical abnormality in a specific part of their brain and are prone to these disturbed signals.

Doctors do not know what causes many types of simple partial seizure disorders but think there may be genetic factors.

Causes of simple partial seizures include traumatic brain injury, which can cause a scar on the brain that can disturb normal brain electrical signals and trigger seizures. Also, brain irritation from surgery, stroke, or tumor can interfere with brain electrical activity and cause simple partial seizures.

People with diabetes may experience a type of continuous simple partial seizures called epilepsia partialis continua (EPC). Addressing and correcting very high sugar levels in the blood can help treat this rare condition. Any other structural abnormality of the brain can also cause EPC.


Types

Other seizure types include complex partial seizures, which do result in a person losing consciousness. This is because the abnormal electrical activity involves both sides of the brain and regions that are important in awareness.

Another type is a generalized seizure, which occurs when a person’s entire brain is affected. People experiencing a generalized seizure do lose consciousness. Symptoms include tonic-clonic (grand mal) convulsions where there is jerking of the arms and legs, or petit mal staring spells where the individual does not respond to directives by anyone around them.

Symptoms

Woman feeling unwell due to simple seizure being attended by paramedic.
A person suffering a simple partial seizure may not always be aware of something being wrong, although it may be a sign that a generalized seizure may follow.

Doctors often classify simple partial seizures into four types based on the area of the brain they affect. The location of the seizure usually determines the symptoms experienced as well.

Motor and sensory simple partial seizures may not change awareness or consciousness. However, some partial seizures can be simple or complex and be associated with autonomic or psychic problems.

Here are more details on these four simple partial seizure categories:

  • Motor: A motor seizure causes a person to lose control over muscle activity, usually in their arm, face, foot, or another part of their body. Due to the way motor nerves cross the brain, if a person loses control over the right side of their brain, it will cause problems on the left side of their body and vice-versa.
  • Sensory: Sensory seizures will cause changes to a person’s hearing, vision, or sense of smell. This can cause hallucinations and difficulty hearing. Also, as in motor seizures, a seizure focus on the right side of the brain can cause numbness or tingling on the left side of the body.
  • Autonomic: Autonomic seizures affect parts of the brain that deal with the functions of the body a person does not control with their thinking. Symptoms could include changes in heart rhythm, blood pressure, and bowel function.
  • Psychic: A psychic seizure causes a person to experience sudden emotional changes, such as feelings of fear, anxiety, or even déjà vu.

Some general symptoms of simple partial seizures that can occur alone or in combination in a given person with no loss of consciousness include:

  • being inattentive but still able to follow commands
  • changes in vision (often one side or the other)
  • difficulty speaking or not speaking for some time
  • feeling as if the skin is crawling (often affecting one side or the other)
  • numbness or tingling on one side of the body (whether the whole side or just part)
  • sweating or feeling anxious
  • decreased movement on one side of the body (whether the whole side or just part)
  • unusual eye movements, such as the eyes moving side to side quickly or gaze fixated in one direction

In some people, a simple partial seizure is a warning seizure that can indicate another seizure is about to occur. They can be a warning of a generalized seizure, which affects the whole of the brain, and causes the person to lose consciousness.

Most seizures do not last longer than 1 to 2 minutes. However, a person may continue to feel confused or have difficulty thinking clearly after a seizure has occurred.

If a seizure lasts longer than 5 minutes, doctors consider it a medical emergency.


Treatment

When a person has experienced multiple seizures, doctors usually prescribe anti-convulsants as the first line of treatment.

However, other treatment options include:

  • treating high blood sugars to decrease focal seizures due to diabetes
  • treating brain swelling caused by a tumor, for example, can reduce the size of a brain region that can trigger a seizure
  • treating the cause of a brain infection, such as herpes encephalitis, can also reduce the risk of a person having a seizure

However, seizure medications or these other treatments may be ineffective in stopping seizures.

Other treatments include:

Diet

One option to treat some forms of simple partial seizures in children is a specialized diet known as a ketogenic diet. Many doctors suggest the ketogenic diet for children who have not responded to other seizure treatments. This diet is a highly restrictive high-fat, low-carb diet that can sometimes be difficult for children to follow. A ketogenic diet requires a dietitian’s supervision.

Surgery

Some people may require surgery to stop their seizures. Surgery involves removing an area of the brain that is causing a person to have seizures. These areas include scar tissue, a tumor, or other abnormalities. Surgery is usually considered a last resort. It might be carried out on people who have not responded to medications, and those where the cause of the seizures is easily accessible.

Vagus nerve stimulator

People who are not candidates for surgery but who are not responding well to their anti-seizure medications may benefit from a device called a vagus nerve stimulator (VNS).

A VNS is a small unit that is placed under the skin in the chest and attached to the vagus nerve in the neck. That vagus nerve runs up to the brain, and the electrical signals released from the VNS change the electrical activity in the brain that causes seizures.

Medications

There is a range of medications available that aim to reduce seizure frequency. Each of the drugs works differently, and sometimes a doctor will prescribe more than one anti-convulsant medication type.

Medication options include:

  • carbamazepine (Tegretol)
  • lamotrigine (Lamictal)
  • oxcarbazepine (Trileptal)
  • phenytoin (Dilantin)
  • valproate (Depakote)

If a person takes anti-convulsant medications, they must not suddenly stop taking them.

To prevent a seizure, the body needs to contain a certain amount of anti-convulsant medications. Suddenly stopping taking the medication can quickly trigger a seizure.

When to see a doctor

Person having EEG.
An EEG may be used to monitor brain waves for simple seizures.

If a person experiences any symptoms that may be a simple partial seizure, they should seek medical attention immediately.

Sometimes, the symptoms of a simple partial seizure may be misunderstood. For example, a teacher or other school official may mistake the symptoms of simple partial seizure in a child as laziness in class or not paying attention.

A doctor will often diagnose epilepsy by considering a person’s symptoms. They will ask friends and family about the symptoms they have observed.

The doctor may order tests to rule out other causes. This could include blood testing, liver tests, or thyroid tests.

Sometimes, the doctor may order a test known as an electroencephalogram or EEG. This test measures brain waves and functioning. If a person has a seizure while being monitored by an EEG, the doctor will collect specific information about the seizure type.

Doctors may also order imaging scans such as a CAT scan or an MRI to identify areas that could be causing seizures.

It is important to note that all tests including the neurological examination performed by the doctor may be normal, yet the individual may still have a seizure disorder or epilepsy.


Outlook

A critical first step in the diagnosis of a person believed to have had one or more simple partial seizures is to determine whether a person has a brain abnormality. This abnormality could be a problem in the structure of the brain, such as a tumor, or it could be that a specific region of the brain is electrically abnormal and causing the simple partial seizures.

Children who have simple partial seizures will sometimes “outgrow” seizures and will not experience them as adults.

Others may need to take anti-seizure medications all their lives.

Simple partial seizures can be treated in a range of ways, such as treating an underlying disease or prescribing a specific medication. Sometimes, simple partial seizures can signal the beginning of a more dangerous (generalized) seizure disorder.

Anybody experiencing any symptoms of a possible simple partial seizure should see their doctor for a definite diagnosis and treatment.

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