Epilepsy and Seizures
Epilepsy is a neurological condition that causes spontaneous, repeated seizures. Seizures occur when there are abnormal electrical impulses in the brain. A single seizure does not necessarily mean that a person will develop epilepsy.
Epilepsy can occur on its own or can be associated with other neurological disorders. Epileptic seizures may cause:
- Changes in sensation, such as taste, sight, smell, vision, and/or hearing
- Changes in motor function, such as tremors, muscle spasms, rigidity, and/or loss of balance
- Behavioral symptoms, such as staring episodes or unconsciousness
There are more than 30 different types of epileptic seizures. The type of seizure a person experiences depends on where the seizure begins in the brain. A partial seizure occurs when there are abnormal electrical impulses in only one area of the brain. General epileptic seizures occur when electrical impulses “storm” or spread through the brain.
How common is epilepsy?
Epilepsy is more common than many realize. It is the fourth most common neurological problem in the United States, after migraine, stroke, and Alzheimer’s disease. One in 26 people will develop epilepsy and approximately 2.2 million people in the United States are living with the disease.
Who gets epilepsy?
Epilepsy and seizures can occur in anyone from the very young to the very old.
Seizures can occur in children with fevers (febrile seizure), which may or may not lead to epilepsy. Injury to the brain, infection (encephalitis or meningitis), certain genetic disorders, and chemical and nutritional imbalances may also cause seizures. Seizures also occur as the result of brain tumors, bleeding in the brain, brain birth defects, or abnormal blood vessels in the brain, among other reasons.
Seizures in older adults can be caused the factors listed above, or by other factors. Seizures in older adults can also be a complication of:
- Heart attacks
- Alzheimer’s disease
- Brain tumors,
- Scar tissue from brain surgery
- Kidney disease
- Liver disease
How is epilepsy diagnosed?
The cause and type of epilepsy must be diagnosed before treatment can begin. Diagnosis of epilepsy usually involves:
The physical examination reveals clues that may help identify the cause of the seizures and helps assess overall health. If questions remain about the diagnosis, additional tests may be needed.
Functional Brain Mapping
Epilepsy diagnosis aims to identify the seizure focus in the brain. Several tests are available for functional brain mapping including
- Functional MRI
- Grid stimulation studies
Imaging of the brain is also used for epilepsy diagnosis. Imaging, such as a CT or MRI, is used to find if there is a lesion responsible for the seizures.
People with epilepsy may experience cognitive problems. Neuropsychological examinations can help explain problems like difficulty in using or understanding language, recognizing spatial patterns, remembering, and/or other mental functions.
Neuropsychological evaluation often helps to identify the seizure focus. For example, patients with left temporal lobe epilepsy typically show a different pattern of results on neuropsychological testing than patients with right temporal lobe epilepsy.
There are different types of seizures, each with unique symptoms. Seizures can be broadly divided into generalized (involving the whole brain) and focal (involving one small part of the brain).
- Absence seizures cause a very brief (a few seconds) loss of consciousness. They begin with little or no warning and may occur several times per day. They are more common in children.
- Myoclonic seizures cause random jerks or twitches, usually affecting both sides of the body, that people often describe as being like an electrical shock.
- Clonic seizures cause repetitive, rhythmic jerks, and involuntary body movements.
- Tonic seizures cause stiffening of the muscles and cause the body to become inflexible or rigid.
- Atonic seizures cause unexpected loss of muscle tone, usually in the arms and legs. This can sometimes cause falls and other accidents.
- Tonic-clonic seizures (formerly known as grand mal seizures) cause 30-60 seconds of the rigidity characteristic of tonic seizures followed by 30-60 seconds of involuntary muscle jerks and contractions. After the clonic phase, most people fall into a deep sleep and may subsequently wake up disoriented or confused.
- Simple partial seizures cause a variety of symptoms depending on where they originate in the brain. They do not involve a loss of consciousness.
- Complex partial seizures cause a loss of consciousness or awareness. Though their eyes usually remain open, people seem distant, out of it, or staring off into the distance. They also may perform repetitive actions like lip smacking and hand waving.
Sometimes partial seizures evolve into generalized tonic-clonic seizures.
Auras and Epileptic Seizures
Many people experience an aura before a seizure. An aura can include a change in taste, vision, or hearing, and may cause the person to suddenly hear a distinct sound, to smell an odor, or to feel unusual. An aura actually can be helpful to someone with epilepsy. Because an aura is a warning that a seizure is imminent, it allows individuals to prepare themselves to prevent an injury.
Please seek the help of a licensed medical professional if you are concerned about your health, and dial 9-1-1 if you are experiencing an emergency.
If you are diagnosed with epilepsy or a seizure disorder, your neurologist may recommend treatment with one or more anti-epilepsy medications. About two-thirds of people with epilepsy who are treated in this way have excellent control of their symptoms with few or no side effects. If you have epilepsy that is not well controlled after a trial of medication, you might be eligible for alternative treatments (vagal nerve stimulation or ketogenic diet) or potentially, epilepsy surgery.
Several effective anti-epilepsy medications are available in the U.S. Choosing one or more epilepsy medications for your treatment requires discussion with your neurologist and epilepsy care team and careful monitoring over time to ensure that you are getting relief from your symptoms with minimal side effects.
There are different types of epilepsy surgery. You may be considered for surgery if you meet the following criteria:
- Seizures are not controlled despite optimal medical management. For most people, this means a trial of at least three medications that are appropriate for the type of seizure, used in adequate doses.
- You experience intolerable side effects from the medications used to control seizures.
- A single “spot” or region in the brain can be identified as causing the seizures.
- The region causing the seizures can be removed safely without causing harm or loss of important functions such as speech or movement.
Decisions about whether to undergo surgery for epilepsy are different for everyone. No one recommendation fits every person. A decision to consider epilepsy surgery does not mean that surgery always is possible. The evaluation may show that you are not a good candidate for surgery. For example, the evaluation may determine that the cause of seizures arises independently from both sides of the brain. Under these circumstances, surgery is seldom advised.
Neurosurgeons may use one of several different procedures to treat epilepsy:
Amygdalohippocampectomy is commonly performed for temporal lobe epilepsy related to mesial temporal sclerosis (scarring and atrophy of the hippocampus in the temporal lobe). Using an operating room microscope, this procedure focuses on minimal resection of the affected tissue and spares the remainder of the temporal lobe.
Temporal lobectomy, or removal of the temporal lobe, is less commonly performed for temporal lobe epilepsy. It is appropriate if temporal lobe seizures are caused by conditions other than mesial temporal sclerosis (cortical malformation, scar, tumor, etc).
Lesion resection is often the preferred operation when a lesion or abnormality resides outside the temporal lobe. A CT or MRI may show a scar, old hemorrhage, tumor, or a cortical malformation. For many people, simply removing the lesion may alleviate their seizures.
Customized neocortical resection is a highly tailored procedure and is often outside the temporal lobe. Patients may or may not have an area of abnormality on brain imaging studies. Surgery is typically performed with intracranial grid seizure recording and functional brain mapping.
Hemispherectomy is a relatively radical procedure that involves the removal of an entire cerebral hemisphere. The procedure is most appropriate for severe and unmanageable epilepsy in infants and children. Candidates for hemispherectomy may have a congenital condition that affects one hemisphere or an acquired disease such as Rasmussen’s encephalitis. Depending on circumstances, the neurosurgeon may perform a total anatomic hemispherectomy (complete removal of the cortical hemisphere sparing deeper structures) or a modified hemispherectomy (partial removal of cerebral hemisphere with disconnection of the remainder of the hemisphere from other brain structures).
Hypothalamic hamartoma resection involves removing a hypothalamic hamartoma tumor from the hypothalamus.
Multiple subpial transection is performed to improve seizure control when the brain tissue causing the seizures cannot be removed because it serves a critically important function, such as speech. The region is “scored” with a probe to disrupt lateral (side-to-side) nerve fibers. The fibers that travel deep, which are more important for local tissue function, are spared.
Corpus callosotomy is a procedure in which the corpus callosum—the largest white matter tract connecting the two halves of the brain—is surgically divided. Corpus callosotomy does not cure seizures; rather, it prevents or slows their spread, making them less severe. This procedure is useful for children with severe drop attacks.
Vagal nerve stimulation is a device similar to a pacemaker that sends mild pulses of electrical activity to the brain, via the vagus nerve, to prevent seizures. The device is placed under the skin on the chest and a wire is placed from it to the left side of the neck where the vagus nerve is located.
The ketogenic diet can be used along with medications to help manage epilepsy in children and adolescents. The ketogenic diet is a high-fat, low-carbohydrate diet that creates a state of ketosis in which the body uses fats for energy rather than carbohydrates. The diet is prescribed and monitored by a physician and dietitian.
- Date of last review: November 26, 2016