Epilepsy is a very common condition that affects approximately 500,000 children in the United States.
Most can achieve control of their seizures with medicines. However, once a child has tried more than one anti-seizure medication without success, the chance of controlling the seizures with medicine alone is low. When that happens, neurologists often consider alternative treatment plans, including:
- Surgical options.
- Dietary treatments.
Neurostimulation is the application of electricity to the brain to help reduce seizures. It is an emerging field in epilepsy treatment.
The Food and Drug Administration (FDA) has approved three methods of neurostimulation for treating adults with focal epilepsy:
- Responsive neurostimulation (RNS).
- Deep brain stimulation (DBS).
- Vagus nerve stimulation (VNS).
VNS also is approved for children with focal epilepsy age 4 years and older. Once more studies are completed on the effects of RNS and DBS, they may be available as options for children as well.
Treatment options explained
In this method, electrodes are placed in the brain near the area where the seizures are thought to start. These electrodes have sensing and stimulating capabilities. When the electrodes sense that a seizure is occurring, they respond by delivering electrical stimulation. Sometimes, this can help stop seizures before they progress or become noticeable to the patient. RNS not only fires when seizures are occurring but also responds to other irregular brain activity, which seems to prevent seizures from occurring.
RNS uses a battery that is placed into the skull and is not rechargeable. Future battery replacements require more surgery on the skull. This may be an important consideration for children whose skulls are still growing. Children also have a longer expected remaining life span than adults, so they may need more surgeries of this kind. RNS data from adults suggest that the average patient has around a 50% reduction in seizures after the first year, with further reductions the longer the RNS is in place. So far, children seem to respond in a similar way.
Deep brain stimulation
In deep brain stimulation, electrodes are placed on each side of the brain deep into a structure called the thalamus. DBS does not have any sensing component and instead delivers stimulation at regular intervals. The DBS battery is usually placed in the chest. In adults, the average patient has a response to DBS that is similar to that of RNS. Deep brain stimulation does not usually require knowing precisely where the seizures are coming from. There is less data for deep brain stimulation in children than in adults, but what is available suggests that DBS is safe and that children and adults respond similarly. As in RNS, special consideration should be given to children whose skulls are still growing.
Vagus nerve stimulation
Vagus nerve stimulation uses electrodes that are placed around the vagus nerve in the neck and are connected to a stimulator placed under the skin in the chest. VNS is FDA approved in the U.S. for children 4 years of age and older and has been implanted in many children worldwide. Vagus nerve stimulation is safe and effective for treating seizures. The best data suggest that the average patient will have a 30% to 40% reduction in seizure frequency after the first year, with further reductions in subsequent years. VNS is like DBS in that the battery is implanted into the chest and it fires at regular intervals. Additionally, newer models of VNS have a heart rate sensing mode and give additional stimulation when heart rate accelerations are detected, because most patients have an elevation in heart rate at the time their seizures begin.
Although VNS is the only FDA-approved neurostimulation method for children, more and more data are emerging suggesting that other modalities are probably as safe and effective in certain children as they are in adults. There is an ongoing study to examine RNS in children, and others may occur in the future for DBS. Some of these studies may expand the use case of stimulation; for example, some have examined using these devices to treat generalized epilepsy. In the future, there may be even more stimulation options, including ones that do not require surgery to administer.
Neurostimulation and emerging noninvasive brain stimulation modalities are a rapidly evolving area for the treatment of epilepsy, especially for children. It is important to work with an experienced team who is leading the research in the field to evaluate your child’s epilepsy condition in detail, facilitate a thorough discussion of treatment options, and identify the best treatment options.
Learn more about how Mayo Clinic’s epilepsy experts can help manage your epilepsy at MayoClinic.org/epilepsy.
Keith Starnes, M.D., is a pediatric neurologist and epileptologist at Mayo Clinic in Rochester, Minnesota. His research is focused on expanding the usage of neurostimulation for epilepsy in the pediatric population, and particularly on emerging noninvasive brain stimulation modalities.