A brain disorder in which a person has repeated seizures (convulsions) over time. Seizures are episodes of disturbed brain activity that cause changes in attention or behavior. There are different types of epilepsy and seizures. Epilepsy drugs are prescribed to control seizures, and rarely surgery is necessary if medications are ineffective.
When someone experiences two or more unprovoked seizures they are considered to have epilepsy. Seizures occur when clusters of nerve cells in a person's brain signal in ways they should not, something that can temporarily alter the person's consciousness, actions, or movements. Epilepsy is something that affects around 3 million people in the United States and approximately 50 million people around the world.
The use of medications and other types of treatments help a number of people from all age groups who experience epilepsy to live with it. Greater than 1 million people still experience seizures that have the potential to seriously limit their school efforts, job prospects, and their participation in everyday life. Epilepsy most often affects people while they are very young or very old, although anyone may develop epilepsy at any age. In America, epilepsy affects more than 300,000 children younger than 15; more than 90,000 of these children experience seizures that cannot be treated adequately.
Number of seniors with epilepsy is rising as the baby boom generation continues to retire. Greater than 570,000 adults age 65 and over have epilepsy. Veterans returning from war are also affected by epilepsy due to traumatic brain injuries.
Epilepsy is the 3rd most common form of neurological disorder in America with a prevalence that is greater than cerebral palsy, Parkinson's disease, and multiple sclerosis combined. Even though epilepsy is common and major advances have been made in relation to diagnosis and treatment, it remains among the least understood of major medical conditions. One in every three adults knows someone who has epilepsy.
Epilepsy and Medications
Several of the newer medications available to treat epilepsy are easier to tolerate than ones that are older. These medications often make people feel less sedated and do not need to be monitored as often. While they are generally approved for use as add-ons to other, standard medications that fail to control a person's seizures, newer medications are many times prescribed as single medications.
The specific medication chosen often depends on the person's particular condition, as well as the specific side-effects of the medication. None of the newer anti-epilepsy medications has demonstrated itself to be superior to either standard or other newer drugs. All of the newer medications seem to give people the same benefits although similar to standard anti-seizure medications; they also have side-effects that can be troublesome.
An extremely troubling issue with anti-epilepsy medications is they all have the potential to increase the risks of suicidal thoughts and behaviors in a person taking them. Research has demonstrated that the highest risk of suicide may happen as quickly as a single week after a person starts taking anti-epilepsy medications, and may continue for a period of 24 weeks as they adjust to the medication. People who take anti-epilepsy medications should be monitored for signs of suicidal thoughts or behaviors.
Epilepsy and Surgery
Surgical techniques involving the removal of injured brain tissue might be an appropriate option for a number of people with epilepsy. The surgeon's goal, of course, is to remove only tissue that have been damaged with the goal of preventing the person from experiencing further seizures, while avoiding brain tissue that is healthy. Surgical techniques for achieving these goals have significantly improved over the last ten years because of advances in imaging, monitoring, surgical techniques, and increased understanding of both epilepsy and the brain.
There are some tests that can help a doctor to determine if surgery is indicated for a person with epilepsy. These tests include the following:
EEG:A number of people with epilepsy have long-term EEG monitoring, which can involve wearing an EEG in everyday life, or while undergoing video EEG. The tests can assist with locating the exact brain tissue that triggers seizures in a person.
MRI: An MRI may help to identify if an abnormality in a person's brain tissue is causing them to experience poorly-controlled seizures.
Advanced Imaging Techniques: These techniques may include Positron Emission Tomography (PET), Functional Magnet Resonance Imaging (fMRI), or Single-Photon Emisson Computer Tomography (SPECT) scans.
If the person's imaging tests indicate there is more than one site in their brain that is involved, or the person's results conflict, a more invasive form of brain monitoring might be needs - although newer imaging tests are very accurate. If the tests pinpoint a specific area of a person's brain as the location causing them to have seizures, surgery is possible. MEG is another type of imaging test that has been approved for use on parts of a person's brain that are involved with things such as sensation, motor control, and language function.
MEG might become important in the evaluation of people who are likely candidates for surgery. A doctor also examines these test results in order to determine if offending nerve cells perform functions that are vital to the person, and attempts to predict the outcome of the surgery in some instances.
A lesionectomy is a type of procedure involving the removal of abnormal tissues under certain conditions. These conditions may include:
A lesionectomy is a, 'local surgery,' with the potential to cure the epilepsy a person is experiencing. The surgery is made possible through the advanced imaging techniques to include MRI scans.
A temporal lobectomy is the most common type of surgical procedure for epilepsy, one that is performed when the epilepsy a person is experiencing starts in the area of the temporal lobe of their brain. The surgery involves the removal of small portions of the person's hippocampus, which is a part of their brain involving memory processing. It is also a part of the person's limbic system, which controls their emotions.
People who are considered to be candidates for this type of surgery commonly have a history of seizures and anti-epileptic medications have not assisted them in controlling the seizure activity they experience. Young children may or may not be considered candidates for this type of surgery because they many times have injured areas of their brains outside of their temporal lobes. Despite this fact, surgery may be highly successful in a number of children, even if more than one area of their brains is involved.
Studies have demonstrated that many people remain seizure-free after undergoing temporal lobectomies. When an area of the person's temporal lobes has been well-described as the source of the seizures they are experiencing, approximately 60% of the people who pursued temporal lobectomies became free of seizure activity after surgery; around 8% of people achieved this success through use of medications. Generally, approximately 60-80% of people remained seizure-free 1 to 2 years after the surgery.
People who pursue this type of surgery might still need to take medications after surgery, even if the seizures they experience are infrequent. A cure is not always a possibility; some people may still experience seizures. Double vision is common after a temporal lobectomy, although it is often temporary and tends to resolve within a period of a few months.
While surgery on a person's left temporal lobe does not impair their level of intelligence to any great degree, some studies have suggested a person may experience negative effects in relation to mental functioning and behavior. There is also a risk of verbal memory impairment. The surgical effects on a person's mental functioning and behavior generally depend upon the location and extent of the area the surgery is performed on. A successful temporal lobe surgery has the potential to improve a person's quality of life while relieving both anxiety and depression.
Vagus Nerve Stimulation
Vagus Nerve Stimulation (VNS) involves electrical stimulation of areas in a person's brain that affect epilepsy, and is something that is helping a number of people with refractory epilepsy. VNS involves electrical stimulation of a person's vagus nerve and is an accepted type of therapy for severe epilepsy that is not responsive to medications. The two vagus nerves are the longest nerves in a person's body.
Vagus nerves run along each side of a person's neck, down a person's esophagus, to their gastrointestinal tract. The nerves affect speech, swallowing, and a number of additional functions, and appear to connect to parts of a person's brain that are involved with seizures. Vagus Nerve Stimulation (VNS) procedure involves the following:
The person has the ability to pass a magnet over the device in their chest in order to give it an extra dose should they feel a seizure coming on; something that seems to help around 25-30% of people. The batteries in a VNS devise wear out after a period of between 3 to 5 years. They need to be removed and replaced, something that can be accomplished through a simple surgical procedure. Candidates for implantation of a Vagus Nerve Stimulation device include the following people who:
Growing evidence indicates; however, that VNS is both safe and effective for a number of people from every age group in relation to refractory epilepsy and a number of other forms. Studies have also indicated the procedure reduces the number of seizures within a 4 month period of time by up to 50%, or even more for many people. The studies also report that VNS has been effective over a period of greater than 7 years.
Complications related to the use of VNS do exist. VNS does not eliminate seizures entirely in the majority of people and remains somewhat invasive. It may cause hoarseness, shortness of breath, coughing, sore throat, nausea, vomiting, ear and throat pain. The side effects of VNS may be reduced, or entirely eliminated, through reduction of the intensity of stimulation.
Studies have been performed suggesting VNS causes adverse changes in a person's breathing while they sleep and might cause their lung functioning to deteriorate if they already have lung disease. People with obstructive sleep apnea need to be cautious about the use of VNS. Turning off VNS for various reasons, such as before surgery or for an MRI scan, might increase a person's risk of status epilepticus. It is important to note that VNS can also be helpful in treating status epilepticus in some people.
Experimental Procedures and Epilepsy
Stereotactic Radio Surgery: Focused beams of radiation have the ability to destroy lesions that may be present deep within a person's brain without requiring open surgery. Stereotactic radio surgery is sometimes used for brain tumors, and is also being investigated for use with temporal lobe epilepsy and seizures caused by cavernous malformations. The type of surgery might also be used for people when an open surgical approach is not possible due to the location of an area, which may be surrounded by delicate brain tissue.
Deep Brain Stimulation: Deep Brain Stimulation (DBS) is an investigational approach which targets a person's thalamus, a part of their brain that produces the majority of seizures. Early results of this approach have demonstrated some benefit. Researchers are studying other implanted nerve stimulation and brain devices such as the, 'Responsive Neurostimulator System (RNS),' a device that detects seizures and stops them by sending electrical stimulation to a person's brain. Another investigational approach call, 'Trigeminal Nerve Stimulation (TNS,' involves stimulation of a nerve involved with inhibiting seizures.