The Latest Research on Epilepsy
We asked Dr. Nathan Fountain, director of the F.E. Dreifuss Comprehensive Epilepsy Program at the University of Virginia School of Medicine to discuss what we know about epilepsy and what patients might expect in the future.
What role do hormones play in epilepsy?
Seizures are an electrical storm in the brain, usually without an identifiable cause. For most people a seizure comes on randomly, without an obvious precipitant, which is one of the most frustrating things about epilepsy. About a third of women think they’re more likely to have a seizure around their period, but for the vast majority of women, they have seizures outside of their menstrual cycle. For women who have what are called catamenial seizures – seizures that occur only around their menstrual cycle in a specific pattern – doctors can prescribe hormone therapy to help reduce the frequency of seizures. However, for women who have a loose pattern of seizures around their period, hormone therapy is not helpful. For some women, seizures may get better after menopause.
For men, hormones don’t seem to play a consistent role in seizure patterns.
How does this affect treatment?
For women who have catamenial patterned seizures around their period, it seems that falling levels of estrogen precipitate seizures and rising levels of progesterone seem to prevent seizures. Therefore, they may, in rare cases, be treated with progesterone or another hormone, but it’s very uncommon for a doctor to prescribe this course of treatment because it is relatively complicated. A randomized controlled trial of progesterone did not find it effective in treating seizures for women who did not have a strictly catamenial seizure pattern.
Some seizure medications tend to interfere with birth control pills or even with becoming pregnant. This is most commonly a problem with older seizure medications that induce liver enzymes, which may lower hormone levels. This means that women taking birth control pills who are also taking seizure medicine need to be careful to make sure the kind of birth control they’re taking is high enough in estrogen content to prevent pregnancy. Fortunately, most of the newer seizure medications do not interfere with birth control pills in this way.
How is epilepsy managed during pregnancy?
The most important thing for a woman with epilepsy is to plan her pregnancy in order to minimize risks to both the mother and baby.
Some seizure medications can cause birth defects. One older medication called valproic acid is known to cause birth defects in about 10 percent of pregnancies and is generally not recommended for women at a reproductive age.
Usually, the risks to the baby associated with seizure medications are lower than the risks of the mother having a seizure. In most cases, it’s better to take the seizure medication and have seizures under control than to run the risks of seizures. However, doctors aim for women to be on the fewest number of drugs and the lowest dose of drugs to achieve stability.
Dr. Fountain encourages all women who have epilepsy and who may become pregnant to register for the North American Antiepileptic Drug Pregnancy Registry so researchers can study the effects of seizure medications on mother and child.
Is epilepsy hereditary?
Most epilepsies are not hereditary, but a few are, depending on what causes the epilepsy. For the vast majority of people, the risk is only slightly increased if the parents have epilepsy. About 3 percent of the general population will experience epilepsy at some point in their life and the risk increases only to about 5 percent if you have a parent with epilepsy. However, if you have a genetic disorder that causes epilepsy, your child’s risk may be higher due to the genetics of the particular disorder. Some epilepsies that bring increased risk to children include tuberous sclerosis, juvenile myoclonic epilepsy, and childhood absence epilepsy, among others. The chance of passing epilepsy on to your children depends on the genetics in your family so it is important to see a genetics counselor if you are concerned about this.
What epilepsy research are you most excited about?
A new era of devices for epilepsy is the most exciting thing happening right now. For people whose seizure medications don’t control their epilepsy, about 25 to 30 percent of people with epilepsy, devices may be a good alternative. There are two devices approved for epilepsy. One is an older device called vagus nerve stimulation (VNS), which stimulates a nerve in the neck from a generator that is placed in the chest. The other device, recently approved, is a technology called responsive neurostimulation (RNS), in which recording electrode wires are placed in the brain at the focal point where seizures arise. From there, the leads are attached to a neurostimulator implanted in the skull, which monitors brain wave activity and when it detects a seizure, it provides a small “zap”, or electrical stimulation, to that part of the brain. The RNS system was granted FDA approval in November, 2013, for the treatment of adults with partial onset seizures that have not been controlled with two or more antiepileptic drugs.
There are other therapeutic devices in development. One is called deep brain stimulation (DBS). With this type of therapy, electrode wires are placed in a deep part of the brain, stimulating the brain regularly in an effort to suppress seizures. Another kind of external stimulation in development is trigeminal stimulation. With trigeminal nerve stimulation, there’s an external stimulator, the size of a mobile phone, with wires that connect to two pads that are placed on the forehead. These pads send a signal to the trigeminal nerve, which extends into the brain. According to Epilepsy Action, the makers say this nerve is known to play a role in the prevention of seizures.
Allison is a former editor for HealthCentral.