Seizure, Temporal Lobe
A temporal lobe seizure starts in the part of the brain that processes emotions. Many people who have these seizures experience odd feelings — ranging from euphoria to fear — at the onset of their seizures.
Because it's typically localized to one part of the brain, temporal lobe seizure is classified as a type of complex partial seizure.
The temporal lobes lie along the sides of your head, just above your ears. Seizures that begin in those lobes often stem from an anatomical defect or scar. But many temporal lobe seizures have an undetermined cause.
These types of seizures affect all age groups. People who have temporal lobe seizures usually remain conscious during a seizure, but they lose awareness of their surroundings and rarely remember what happened. Signs can include lip-smacking or picking at clothes.
Temporal lobe seizures are particularly resistant to anti-seizure medications. Surgery may be a good option for many people, especially if their seizures consistently begin in the same location within the temporal lobe. Many people become seizure-free when the affected portion of the lobe is removed.
During normal waking and sleeping, your brain cells produce varying electrical activity. If the electrical activity from these cells becomes abnormally synchronized, a convulsion or seizure may occur.
Temporal lobe seizures can be a result of :
- Traumatic injury
- Infections, such as encephalitis or meningitis, or history of such infection
- Lack of oxygen
- Blood vessel malformations in the brain
- Brain tumors
- Genetic syndromes
When to seek medical advice :
Seek medical advice in these circumstances :
- When a seizure lasts more than two minutes
- When a new seizure immediately follows a completed seizure
- When new signs or symptoms of seizures appear
If rhythmic muscle contractions or jerky movements occur in someone having a temporal lobe seizure, a grand mal seizure may be developing. Follow these tips :
- Call for medical help immediately
- Gently roll the person onto one side and put something soft under his or her head.
- Loosen tight neckwear.
- Don't put anything in the mouth — the tongue can't be swallowed.
- Don't try to restrain the person. Look for a medical alert bracelet, which may indicate an emergency contact person and other information.
An unusual sensation or emotion, known as an aura, may precede a temporal lobe seizure, acting as a warning. Not everyone who has temporal lobe seizures experiences an aura, and those who do have an aura may not remember it. The aura is actually a small seizure itself — one that may not spread into an observable seizure that impairs consciousness and ability to respond. Examples of auras include :
- A sudden sense of unprovoked fear
- A deja vu experience
- The sudden occurrence of a strange odor or taste
- A rising sensation in the abdomen
The characteristics, signs and symptoms of the seizure include :
- Duration of 30 seconds to two minutes
- Loss of awareness of surroundings
- Repeated swallowing
- Making picking motions with the fingers
After a temporal lobe seizure, you may have :
- A brief period of confusion and difficulty speaking
- Inability to recall the events that occurred during the seizure
- Unawareness of having had a seizure until someone else tells them
In extreme cases, what starts as a temporal lobe seizure evolves into a grand mal (tonic-clonic) seizure — featuring convulsions and a loss of consciousness. However, many people with temporal lobe seizures never experience a grand mal seizure.
Your doctor will need a detailed description of your seizures. This may need to come from someone who has witnessed your seizures, because most people who have temporal lobe seizures don't remember the episodes.
During the office visit, your doctor may perform a neurological exam that tests your reflexes, muscle tone, muscle strength, sensory function, gait, posture, coordination and balance. Your doctor may also ask questions to test your thinking, judgment and memory.
Blood tests may be needed to check for problems — such as infections, lead poisoning, anemia or diabetes — that could be causing or triggering your seizures. Your doctor may also suggest scans or tests designed to detect abnormalities within the brain.
An EEG displays the electrical activity of your brain via small electrodes affixed to your scalp with paste or an elastic cap. You lie still during the test, but at times you may be asked to breathe deeply and steadily for several minutes or to stare at a patterned board. At times, a light may be flashed in your eyes. Typically, a recording during a brief period of sleep is obtained as well. The electrodes pick up the electrical impulses from your brain and send them to the EEG machine, which records your brain waves on a moving sheet of paper or digitally on a computer.
In some cases, your doctor may recommend video-EEG monitoring. This can be helpful because it allows your doctor to compare — second by second — the behaviors observed during a seizure with your EEG pattern from exactly that same time. The comparison helps your doctor pinpoint exactly where your seizures originate, which aids treatment decisions.
Video EEGs usually require hospitalization. The average hospital stay is three to five days. The hospital-based epilepsy monitoring unit is open 24 hours a day and seven days a week. During this hospital stay, you will be videotaped continuously and the EEG will be recorded the whole time, so that if you have a seizure, the data will be collected.
Magnetic resonance imaging (MRI)
An MRI machine uses radio waves and a strong magnetic field to produce detailed images of your brain. MRIs can reveal brain abnormalities that could be causing your seizures. Dental fillings and braces may distort the images, so be sure to tell the technician about them before the test begins.
During the test, you will lie on a padded table that slides into the MRI machine. Your head will be immobilized in a brace, to improve precision. The test is painless, but some people experience an uncomfortable feeling similar to claustrophobia inside the MRI machine's close quarters. If you think you may have a problem like this, your doctor can prescribe anti-anxiety medications beforehand.
A special type of MRI — called functional MRI (fMRI) — can measure the small metabolic changes that occur when a part of your brain is working. An fMRI can record which areas of your brain are working when you perform certain tasks, such as rubbing a block of sandpaper or answering simple questions.
Doctors know the general areas of the brain responsible for such tasks as thought, speech, movement and sensation, but the precise locations vary by individual. An fMRI can identify the locations of these critical functions so that your doctor can determine if epilepsy surgery would be a safe option for you.
Positron emission tomography (PET)
PET scans use injected radioactive material to help visualize active areas of the brain. The radioactive material is tagged in a way that makes it attracted to glucose. Because the brain uses glucose for energy, the parts that are working harder will be brighter on a PET image.
After the radioactive material is injected, it will take between 30 and 90 minutes for the substance to accumulate in your brain tissue. During this waiting period, you will be asked to rest quietly and not talk or move around much. The actual scan takes 30 to 45 minutes. The amount of radioactive material used in the test is very small, and its glucose-binding activity in the brain lasts only a short period of time.
Single-photon emission computerized tomography (SPECT)
This type of test is used primarily in people being evaluated for epilepsy surgery when the area of seizure onset is unclear on MRIs or EEGs. SPECT imaging requires two scans — one during a seizure and one 24 hours later. Radioactive material is injected for both scans and then the two results are compared. The area of the brain with the greatest activity during the seizure can be superimposed onto the person's MRI, to show surgeons exactly what portion of the brain should be removed.
Recurrent temporal lobe seizures can lead to physical harm. A seizure that produces either loss of awareness or control can be dangerous if you're driving a car or operating other equipment. Many states have licensing restrictions related to your ability to control seizures. For children, seizure disorders may result in limitations of physical activities. In addition, for both children and adults, seizures can cause falling and associated injuries, such as head injury. People with epilepsy should not take unattended baths, swim without taking precautions or work at heights, such as on a ladder.
Many children outgrow temporal lobe seizures, but this is less likely if brain scans show a defect or scar where the seizures are originating. The defect or scar makes these seizures more difficult to control with medications. But it can also make the person a good candidate for surgery, since there is a well-defined target for removal.
Treatment typically doesn't begin until you have experienced at least two seizures. Most of the medications used to control seizures are taken by mouth.
Several standard anti-seizure drugs have been in use for decades. Newer anti-seizure drugs, most of which became available in the late 1990s, are generally no more effective in controlling seizures than are the standbys. The recently developed drugs may, however, have fewer side effects.
Common side effects with all anti-seizure medications may include fatigue and dizziness. More than 70 percent of the people who have temporal lobe seizures continue to have seizures despite taking anti-seizure drugs.
Surgery for temporal lobe seizures has the highest success rate of all epilepsy surgery. At least 75 percent of these procedures result in a cure. Some studies place the success rate at over 90 percent. These high success rates are due to the nature of temporal lobe seizures, which typically are linked to a defect or scar in the brain. Removing the defect or scar stops the seizures. But surgery is rarely an option if your seizures originate from a region of the brain that contains vital brain functions.
Before the procedure, you'll need a comprehensive evaluation, with magnetic resonance imaging scans of your brain and, usually, observation of your seizures in a hospital-based monitoring unit using video recordings and EEG.
During the procedure, your surgeon makes an incision in your scalp and removes a piece of the skull bone. He or she then cuts into or removes the area of the brain that's causing the seizures.
Although many people continue to need some medication to help prevent seizures after surgery, you may be able to take fewer drugs and reduce your dosages. In some cases, surgery for epilepsy can cause complications, such as permanently altering your cognitive abilities. Talk to your surgeon about his or her experience, success rates and complication rates with the procedure you're considering.
Vagus nerve stimulation
A device called a vagus nerve stimulator may be an option if medications are ineffective or cause serious side effects. The stimulator is implanted into your chest under the collarbone. Wires from the stimulator are attached to the vagus nerve in your neck. The device turns on and off according to an adjustable program, and can be activated with a magnet.