Why did the doctor tell me not to sleep before my EEG?
Even though seizures are usually unpredictable, we know that some things make them more likely. Many sorts of physical or emotional stress, including illness and lack of sleep, can increase the chance of seizures. So people with epilepsy are usually told to avoid sleep deprivation, as well as substances like alcohol that interfere with normal sleep.
A doctor who believes you may have epilepsy will often recommend anelectroencephalogram (EEG) to confirm the diagnosis and learn more about your specific type of seizures. Because certain abnormalities are only seen during sleep, it is important for you to sleep during the study. Therefore, you may be asked to come to the test sleep-deprived. Although this is contrary to the usual recommendation, it will make the test more accurate and complete. It also may increase the likelihood that the test will show any abnormal activity.
I'm drowsy during the day. Why?
Daytime drowsiness is not unusual for people with epilepsy. If you find it troublesome, you should ask your doctor to investigate. It may be related to persistent seizures or to seizure medicines. Or it may just be the same kind of drowsiness that affects many Americans these days because their sleep is inadequate or is disrupted by things like noise, alcohol, or caffeine. Having epilepsy does not protect you from also having an unrelated sleep problem.
If you do have a sleep disorder, it can worsen your epilepsy and your epilepsy can worsen your sleep. You can therefore develop a cycle of worsening seizures and worsening sleep, which can make it difficult to treat either problem. If you have epilepsy, you should pay particular attention to the conditions of your sleep and possible disruptions.
The most troublesome sleep disorder in people with epilepsy is sleep apnea, in which breathing stops briefly during sleep. Sleep apnea affects at least 2% of the general population. It is most common in people who are overweight. As sleep deepens, the airway relaxes too much and becomes blocked. The brain recognizes the resulting lack of oxygen, and the person wakes up (usually with a loud snore) and begins to breathe again. Often the person does not remember waking up, but this cycle is repeated all night long and normal sleep is never achieved. Therefore the person is drowsy most of the time and may be at risk of falling asleep during activities like driving.
It's especially important to recognize and treat sleep apnea if you have epilepsy. The lack of sleep can make your seizures worse. So can the lack of oxygen getting to your brain during sleep. You may continue to have seizures (particularly during sleep) even if you take seizure medicines that would otherwise be effective. Both your drowsiness and seizures should improve if the sleep apnea is treated.
If I have a seizure when I'm asleep, is that a problem?
Seizures usually last only a minute or two. Most people recover rapidly and can function pretty normally within 10 or 15 minutes. Recovering from a generalized seizure may take a bit longer. But a substantial number of people with epilepsy find that they do not function at their best for a day or more after a seizure. This group includes many people who have seizures during their sleep.
In some ways, seizures during sleep are less disruptive. Certainly you are less likely to be injured by falling or having some other kind of accident. But you may not be able to concentrate or work well the following day. Not all the reasons for this problem are clear, but disruption of sleep probably plays a large role.
The effect of a seizure on sleep patterns is much more profound and long-lasting than just the effect of waking up once at the time of the seizure. Sleep consists of very complicated cycles, during which people progress through different stages. The lighter stages, 1 and 2, usually happen first upon falling asleep, and account for about half of the total sleep time. During a normal night, you will then progress into deeper sleep, stages 3 and 4, which are also known as slow-wave sleep. REM (rapid eye movement) sleep occurs next. REM sleep is the stage when you have the most vivid dreams. Normally, people cycle through all of these stages several times during the night.
A seizure during sleep affects sleep patterns the rest of the night. Sleep becomes lighter, with more stage 1 sleep and more frequent awakenings. The most profound effects are on REM sleep. It is greatly reduced and sometimes eliminated by even a brief seizure early in the night. Daytime seizures also can also reduce REM sleep the following night, but the effect is weaker.
Why worry about these changes? We don't completely understand the function of REM sleep, but there is a lot of evidence that it is important. If you do not get enough REM sleep one night, the next time you sleep you will have less light sleep and more REM to make up for the loss (a pattern known as "REM rebound"). This tells us that REM sleep is important but it does not tell us why. We do have evidence that REM sleep is essential for at least some types of memory, and probably for concentration as well. If you are short on REM sleep, therefore, you may have a problem with memory and concentration the following day, even if you don't feel drowsy.
We don't know any way to create more REM sleep, so what should you do if your sleep is being disrupted by seizures? Clearly, it is essential to try to eliminate the seizures. If your seizures are not fully controlled, your doctor should refer you to an epilepsy center. Different medications may control your seizures, or you may be a candidate for epilepsy surgery. If it is impossible to stop all your seizures, you should be especially careful to get enough sleep, particularly in the day or two after a seizure.
Will my seizure medicine affect my sleep?
Most people with epilepsy take seizure medicines. Whether they fully control seizures or not, the medications themselves may result in tiredness, memory problems, or difficulty concentrating. Some of them, such as phenobarbital and Klonopin (clonazepam), can actually be used as sedatives. They change the structure of sleep and particularly affect REM sleep. Even medications like Dilantin or Phenytek (phenytoin) and Tegretol or Carbatrol (carbamazepine), which are not considered sedatives, also decrease REM sleep and therefore may contribute to memory problems. Lamictal (lamotrigine) may cause difficulty falling asleep.
Other seizure medicines, such as Neurontin (gabapentin) and Depakote (valproate), are thought to have little effect on sleep. We don't yet know the effects of some of the newest medications, such as Trileptal (oxcarbazepine), Keppra (levetiracetam), and Zonegran (zonisamide).
Consider the story of a 25-year-old student who had partial seizures that consisted of staring, lip smacking, and interrupted speech. She did not remember what happened during her seizures. She first took Tegretol, but as the dose was increased she started to feel tired during much of the day and had trouble concentrating on schoolwork. She stopped having seizures and she thought she was sleeping well. But because she felt constantly tired, she was switched over to Neurontin. Almost immediately, she felt more alert and energetic. She still had no seizures and she felt much better. The Tegretol had probably been changing the quality of her sleep, making it less effective. The change in medication corrected this problem, and once again she was able to function at her best.
Not everyone is sensitive to any particular medication. Some do fine while taking Tegretol. But if your memory or concentration seems to be suffering, it is possible that your seizure medicine is causing a problem with sleep. (This possibility is particularly likely if you are not having any seizures, which can cause similar difficulties.) Ask your doctor about changing to a different medication.
I've heard about different kinds of EEGs and other tests. Which ones do I need?
The electroencephalogram, or EEG, is a completely safe and painless test that is performed on most people who are suspected of having seizures. It shows brain waves so the doctor can look for patterns known to be associated with epilepsy. As already mentioned, because abnormalities associated with epilepsy are more common during sleep, the doctor often will try to obtain a recording while you are awake and while you are asleep.
Sometimes the doctor will ask you to stay awake all night before an EEG. This is called a sleep-deprived EEG. Because of the lack of sleep, your brain should have more abnormal electrical discharges than usual. This special EEG can be very helpful in making a diagnosis.
If the diagnosis is still uncertain after one or more EEGs, the doctor may recommend a prolonged EEG, also called an ambulatory (walking around) EEG. This kind of recording shows a long sample of your brain waves and will include deep sleep, which is not typically recorded with a routine EEG. You can have this kind of test at home, with equipment that you carry with you, or you may stay in the hospital for a time.
Another way of clarifying a diagnosis of epilepsy is to admit you to a video-EEG monitoring unit, usually for several days. During this time, you will be videotaped at the same time as your brain waves are recorded. This allows specialists to determine whether there are abnormalities in your brain activity that are consistent with seizures during any seizure-like episodes. They also can get valuable information about the location of seizure activity in your brain.
Standard EEG recordings for epilepsy do not evaluate sleep disorders. Most people with epilepsy do not have a sleep disorder, but if you are someone who has both epilepsy and a disorder such as sleep apnea, you probably should have a sleep study. In this test, you will sleep in a laboratory. Your breathing, muscle tone, eye movements, and brain waves will be measured electronically to see if your sleep patterns are normal and, if not, to determine what sort of problem is present.
What should I remember about sleep?
People with epilepsy are particularly vulnerable to the effects of sleep disruption, and unfortunately seizures and the medications used to control them can contribute to this problem. If you have problems with drowsiness or trouble with your memory or concentration, even when you seem to be spending enough hours asleep, you may need a change of seizure medicine or a sleep study. To achieve your best overall level of function, you must pay attention to the relationship between your seizures and your sleep.
