Also called: Complex Partial Seizures, Focal Seizures, Simple Partial Seizures
A partial seizure is a sudden change in consciousness, muscle control or behavior caused by abnormal activity in an isolated part of the brain. A partial seizure is different from a generalized seizure, which usually involves the entire brain.
Seizures occur when the neurons in the brain suddenly increase activity, causing an electrical storm that can overwhelm the brain. This can result in a variety of symptoms, depending on the area of the brain affected. Anything that disrupts the normal function of the brain can cause seizures. Although roughly half of all seizures have no known cause, there are certain factors that may trigger seizures, such as head injury, genetic abnormalities, alcohol withdrawal and brain tumors.
Partial seizures are generally categorized as being either complex or simple. Complex seizures usually originate in the temporal lobe of the brain. During a complex partial seizure, the person may stare into space and perform seemingly conscious tasks, which are known as automatisms. When the seizure is over, the person rarely has any recollection of the seizure. During a simple partial seizure, people are awake and aware, although they have no control over their actions. Simple seizures are usually further categorized according to the area of the brain affected.
Many partial seizures occur only once and require no treatment. However, people with recurring partial seizures may be treated with seizure medications. People who are unable to control seizures with medication may be candidates for brain surgery to remove the affected area of the brain responsible for the seizures.
About partial seizures
Seizures can be categorized as either partial or generalized. A partial seizure is a sudden change in consciousness, muscle control or behavior caused by abnormal activity in an isolated part of the brain. In generalized seizures, the entire brain is affected.
It is often difficult to identify whether a seizure is partial or generalized. Roughly 60 percent of people with epilepsy (condition marked by recurrent seizures) experience partial seizures, according to the National Institute of Neurological Disorders and Stroke (NINDS). In addition, partial seizures can sometimes trigger generalized seizures if the initially localized abnormal activity spreads to other parts of the brain.
Seizures involve a sudden increase in electrical activity in the brain. Neurons (nerve cells) normally produce electrochemical signals that instruct other parts of the body to perform certain actions, such as moving the body or feeling certain emotions or sensations.
A seizure occurs when something disturbs the pattern of electrochemical signaling and causes the neurons to fire at a much faster rate than normal. This storm of electrical activity in the brain can result in a seizure, possibly producing changes in mood or behavior, hallucinations, involuntary muscle contractions, loss of consciousness or involuntary movements. During a partial seizure, the symptoms that are experienced depend upon the area of the brain affected.
Partial seizures can be categorized as being either simple or complex. During a simple partial seizure, consciousness is not lost. However, it may be altered. People who have simple partial seizures may experience abnormal sensations such as inexplicable feelings of joy, anger or sadness. They may also see, hear, smell or taste things that are not really there (hallucinations).
During a complex partial seizure, people may experience a pronounced change in or loss of consciousness. They may appear to be “out of it” or in a dream-like state. They may also make repetitive movements that appear to be conscious (called automatisms), such as smacking the lips or picking at clothing.
Complex partial seizures may sometimes develop into a generalized seizure, most often a tonic-clonic seizure. When this occurs, it is sometimes called a partial onset seizure or secondary generalized seizure. In some cases, there is a clear difference between the initial partial seizure and the secondary generalized seizure. However, in other cases, the generalized seizure is triggered so fast that physicians may have difficulty identifying that an initial partial seizure preceded the generalized seizure.
Most partial seizures have no known cause. Some types of partial seizures are more likely to be caused by certain factors, such as head injuries or brain tumors. Under certain circumstances (e.g., electrical stimulation, high fever, exposure to certain drugs), anyone may experience a seizure. Having a single partial seizure, even one that is seemingly unprovoked, does not necessarily mean another seizure will occur. However, recurrent partial seizures, especially of the same type, may be an indication of a chronic underlying neurological condition.
Experiencing a partial seizure may be distressing. People who have a simple partial seizure are generally aware of changes that may occur (e.g., hallucinations), although they cannot control them. This may be especially worrisome for children with seizures, who often need reassurance from caregivers during and after the seizure. People who have a complex partial seizure are generally not aware of their actions during the seizure, although it may seem as if they are performing conscious tasks (e.g., chewing, swallowing, undressing themselves). This can sometimes be troublesome for the person having the seizure, whose actions may be misunderstood by onlookers.
Other symptoms related to partial seizures
In addition to the involuntary muscle contractions and impaired consciousness often seen with partial seizures, certain types of sensory abnormalities may occur. These may appear when areas of the brain associated with processing sensory information or emotions are affected. These sensory symptoms include:
- Visual changes (e.g., hallucinations)
- Abnormal tastes, smells
- Sense of déjà vu (feeling as if one is repeating a particular situation)
- Sudden, intense emotions (e.g., fear, joy)
Some people who have partial seizures that originate in the temporal lobe of the brain also experience symptoms such as a flushed sensation, sweating, nausea or abdominal pain before or during the seizure.
Immediate medical attention should be sought if a person has no history of previous seizures, or if any of the following symptoms occur:
- Physical injury is sustained during the seizure
- The seizure lasts 5 minutes or longer
- The patient fails to regain a normal state of mind within an hour after a seizure
Types and differences of partial seizures
Partial seizures may be categorized as either complex or simple. They are then further characterized according to the area of the brain that is primarily affected.
Complex partial seizures usually originate in the temporal lobe of the brain. This area of the brain is associated with some aspects of memory, speech, emotions and the sensations of sound and smell. Although seizures may vary widely between individuals, most complex partial seizures last from 30 seconds to up to two minutes. During this time, the following sequence of events may take place:
- Some people experience an aura directly before the complex partial seizure occurs. The exact nature of the aura is often unique to each individual. It may include noticing a strange taste in the mouth, a rising sensation in the chest, an odd smell, the twitching of a limb that may or may not spread, or an inexplicable feeling of fear or apprehension.
- A person may stare into space or directly at another person or object, although the patient does not recognize the object of the stare. People experiencing a complex partial seizure will not be able to hear or respond to questions or requests, even though it may appear as if they are aware of their surroundings.
- During a seizure, a person may perform complex actions that appear purposeful. These are called automatisms. They range from lip-smacking, teeth-sucking or picking at clothes to more complex movements such as undressing or searching for something.
- After the complex partial seizure, most people have no memory of the seizure or what actions they may have performed during the seizure. They may be confused, tired or otherwise disoriented. These feelings may last for a few hours following the seizure.
The main difference between a complex and simple partial seizure is that people who only have a simple partial seizure do not lose consciousness and are usually aware that they are having a seizure. People with complex seizures lose awareness during the seizure and may lose consciousness. However, like any other type of seizure, people who have partial seizures of either type are not in control of their actions during the seizure.
There are numerous types of simple partial seizures. They rarely last for more than two minutes and may be so short that a person is not aware that a seizure took place. Simple partial seizures can affect any area of the brain and cause various symptoms. These localized seizures may be categorized by the area of the brain affected, such as:
- Temporal lobe seizures. Simple temporal lobe seizures can vary in type and intensity. Because the temporal lobe is responsible for many aspects of sensation and behavior, people who have a simple temporal lobe seizure may experience intense feelings or emotions (e.g. elation, anger, fear). They may also have vivid memory flashbacks or feelings of déjà vu. This is because the temporal lobe is associated with aspects of memory. These occurrences are similar to the auras that are sometimes experienced prior to complex partial seizures or generalized seizures. Simple temporal lobe seizures can be very mild and, in some cases, are mistaken for ordinary emotional responses or memory “tricks.”
- Frontal lobe seizures. The frontal lobe controls many aspects of motor function and some parts of speech. Seizures that involve this area of the brain are sometimes called motor seizures and may involve tonic (stiffening of the muscles) movements in just one arm or leg. This is sometimes followed by clonic (rapid contraction and release of muscles) movements in the same body part. People who have a frontal lobe seizure may also experience disturbances in their ability to speak or be understood. These brief seizures are usually followed by a period of weakness.
- Parietal lobe seizures. These simple partial seizures are sometimes called sensory seizures because they involve alterations in physical sensations. This may be no more severe than a numbness or tingling sensation in an area of the body. People who have a parietal lobe seizure may also experience motor function abnormalities during the seizure because the parietal lobe is closely associated with the frontal lobe.
- Occipital lobe seizures. The occipital lobe of the brain is associated with vision, and people who have this type of simple partial seizure may experience hallucinations or other vision disturbances.
Potential causes of partial seizures
Partial seizures may be caused by anything that disrupts normal functioning of the brain. This may include damage or injury to a specific part of the brain due to conditions such as head injury, stroke, brain tumor or infection (e.g., meningitis).
Other potential causes of partial seizures include:
- High fever
- Medication interactions
- Substance abuse or withdrawal
- Genetic abnormalities
- Metabolic abnormalities
In some cases, no cause can be identified.
Treatment and prevention of partial seizures
If a person experiences a partial seizure, a physician may conduct a series of tests to identify the cause of the seizure. This usually includes imaging tests, such as magnetic resonance imaging (MRI) and computed axial tomography (CAT) scans to look for signs of brain damage or tumors. Additionally, a physician may recommend an electroencephalogram (EEG), which involves electrodes being placed on the scalp to measure brain activity. Blood tests may also be performed to rule out metabolic disorders or infections.
Many patients who experience a single partial seizure may not need any type of treatment. However, it is recommended that patients who experience a seizure for the first time consult a physician to identify any existing condition that may have caused the seizure and may require treatment.
Treatment of partial seizures may vary, depending on its cause. Treatment may include surgery in some cases of head injury or brain tumors. Medications may be used if metabolic disorders are associated with a patient’s seizures. Seizure medications may be used for patients with recurrent partial seizures who have been diagnosed with epilepsy. This medication helps to prevent recurring seizures, but must be taken daily to be effective.
Surgery may be recommended for patients with recurrent partial seizures for whom medication does not work. Brain surgery may be effective for patients in which abnormal electrical activity occurs within a clearly defined area of the brain. Surgery may not be recommended when abnormal activity occurs in an area of the brain essential for language or motor (movement) functioning.
Risks of brain surgery include personality changes or increased seizure frequency. Most people who undergo brain surgery for recurrent seizures are advised to continue taking seizure medications for a period of time following surgery to allow the brain to adapt. The patient may then be tapered off the medication.
Another treatment option for people with recurrent partial seizures that are poorly controlled with medication is vagus nerve stimulation. The vagus nerve travels from the brain to the abdomen and controls many aspects of body function. People with recurrent partial seizures may have a device (similar to a pacemaker) surgically implanted into the skin that stimulates the vagus nerve through a series of small electric shocks. These shocks can reduce seizure frequency in people with epilepsy by 20 to 40 percent, according to the National Institute of Neurological Disorders and Stroke (NINDS). This treatment method is FDA (Food and Drug Administration) approved and mainly used to treat partial seizures. However, some studies have shown that it may be used to treat generalized seizures that have not responded well to medications.
Most partial seizures have no known cause, making them difficult to prevent. Because some partial seizures may be caused by head injuries, wearing appropriate head protection when riding bicycles or motorcycles, or when playing contact sports is important. People can also reduce the risk of stroke, which can be a cause of seizures, by eating a healthy diet, quitting smoking and controlling high blood pressure. Binge drinking (consuming large amounts of alcohol in a short amount of time) and illegal drug use should also be avoided.
Questions for your doctor about partial seizures
Preparing questions in advance can help patients to have more meaningful discussions with healthcare providers regarding their condition. Patients may wish to ask their doctor the following questions related to partial seizures:
- What type of partial seizure did I have?
- How do you know it was a partial seizure?
- Do you think my seizure was provoked? What could have caused it?
- If my seizure was unprovoked, do you think I have epilepsy?
- Will you need to speak to people who witnessed the seizure to confirm your diagnosis?
- What kind of treatment do you recommend for me? Are there risks involved?
- How will you identify any underlying medical conditions that may be related to my seizure?
- How long will I require treatment?
- Is there a chance I could have another seizure?
- What should I do if I have another seizure?
- What can I do to reduce my risk of seizures?
- What should I do if my child or loved one has a seizure?