Epilepsy has a lifetime prevalence of 7.6 per 1,000 people, and one-third of those with the condition to not respond to pharmacological treatment. The condition can be debilitating, with people have seizures multiple times a day in some cases. For some patients, drug treatment may reduce frequency of seizures, but even with many anti-seizure drugs on the market, many people still can not achieve relief. The condition can even be fatal and is attributed to around 6,000 deaths a year in the US alone.
In the article Treating Epilepsy’s Toughest Cases,David Noonan briefly goes over classifying the types of seizures that epileptic patients may experience. Epilepsy can be broadly characterized as either generalized or focal, meaning seizures either occur in all areas of the brain or only in a particular region, respectively. Beyond this, there are different types of seizures, including tonic-clonic, also known as grand mal, which is what most TV shows and movies typically use to depict seizures. In this type, a person loses consciousness and their whole body shakes and spasms. There are also absence seizures, previously known as petit mal, where a person essentially “zones out” and is completely unaware of their surroundings, but does not lose consciousness. There are also atonic seizures, clonic seizures, tonic seizures, and myoclonic seizures, although these are all less common.
The article then goes on to talk about certain treatments for those whose epilepsy does not respond to drug therapy. Noonan cites a 2014 study done by GW Pharmaceuticals in which a pharmaceutical version of cannabidiol was shown to reduce seizures by 42%. Cannabidiol is a non-psychoactive component of the marijuana plant, and has even been given to some infants with Dravet syndrome, a genetic condition causing seizures, in states where medicinal use of the plant has been legalized. In these cases, families have reported significant reductions in seizures. Noonan also brings up the ketogenic diet, which was used in the 1920s to help treat seizures and is now making a popular comeback. Additionally, devices similar to pacemakers have been developed. One type stimulates the vagus nerve in a constant but mild pattern and has been shown to reduce seizures by more than half in 50% of patients. Another, newer type only sends out stimulatory currents when it detects unusual electrical activity and have been shown to reduce seizures by up to 66%.
In Dr. Hui Ye’s research, he has found that time-varying magnetic fields can cause reductions of seizures in the hippocampus in mice. “Mini coils” are implanted into the hippocampus in a particular orientation and placement, and seizures are pharmacologically induced. The amount of stimulation and duration provided by the “mini coil” was varied in order to see what effects strength and duration had on the seizures. For the conditions using 50 Hz and 100 Hz stimulations lasting 10 seconds, there was a significant decrease in neuronal activity during stimulation, but this activity returned to baseline levels after stimulation ceased. When 200 Hz stimulation was applied for 10 seconds, there was a significant increase in neuronal activity during stimulation, and a slight reduction from baseline activity after stimulation ceased. This gave the promise of further reduction of activity following stimulation, so Dr. Ye experimented with 200 Hz and 400 Hz stimulations at various durations. He found that with higher frequencies and longer durations of stimulation, seizure activity could be suppressed for longer periods of time.
While Dr. Ye’s work is promising in the reduction of hippocampal seizure activity, it is unknown if these findings can be generalized to seizures in other areas of the brain or for generalized seizures. It is also unknown if this type of magnetic field stimulation could be used as a treatment for other types of seizures, or if it only applies to the type of seizure that was pharmacologically induced in these mice. In addition to this, the seizures being pharmacologically induced raises some concerns. Although the mice showed seizure suppression in some treatment conditions, seizure activity returned after a short time of a minute or so. This could potentially be because of the drug that is still in the mouse’s body. In a non-induced seizure, no drug would be present, so from Dr. Ye’s work it is unclear if seizures activity would continue again after suppression, or if the magnetic stimulation would be enough to suppress it entirely.
Ultimately, all the current treatment options being explored offer hope for those with epilepsy that does not respond to drug treatment. From cannabidiols and diet changes to “brain pacemakers” and magnetic stimulation, future treatments for epilepsy are promising, however more generalizable research needs to be done to test their efficacy in various types of seizures.
References
Ye, Hui, and Amanda Steiger. "Neuron Matters: Electric Activation Of Neuronal Tissue Is
Dependent On The Interaction Between The Neuron And The Electric Field". Journal Of
Neuroengineering And Rehabilitation, vol 12, no. 1, 2015. Springer Nature,
doi:10.1186/s12984-015-0061-1.
Ye, Hui et al. “Transmembrane Potential Induced In A Spherical Cell Model Under Low-Frequency Magnetic Stimulation”. Journal Of Neural Engineering, vol 4, no. 3, 2007, pp. 283-293. IOP Publishing, doi:10.1088/1741-2560/4/3/014.
Noonan, David. “Treating Epilepsy’s Toughest Cases.” Scientific American, 1 April 2016, https://www.scientificamerican.com/article/treating-epilepsy-rsquo-s-toughest-cases/.
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