Epilepsy & Seizures
Written By: Jennifer Huan, Daniel Kiernan, and Anisha Bhole
Seizures are one of the most common brain conditions in the United States which are caused by a sudden, uncontrolled electrical disturbance in the brain. When a seizure occurs, individuals may experience different levels of loss of consciousness or control of their bodies. Seizures that occur more than two times are more aptly categorized as epilepsy. According to the Centers for Disease and Control and Prevention, “In 2015, 1.2% of the US population had active epilepsy. This is about 3.4 million people with epilepsy nationwide: 3 million adults and 470,000 children.”
There are many possible causes of a seizure including genetic influence, head trauma, brain conditions (tumor/stroke), infectious diseases, prenatal injury, or developmental disorders. It may also vary by age and other factors such as pollution or drug abuse. Seizures can be best categorized into two different groups: focal and generalized seizures. Focal seizures occur when there is abnormal activity in just one area of the brain. These seizures may impair awareness, however, the person does not lose consciousness. On the other hand, generalized seizures usually involve more than one area of the brain and are much more serious than focal seizures since the person may completely lose their consciousness.
Epilepsy is a many-sided and misunderstood condition. Interestingly, it is not synonymous with having seizures — one may have seizures without having epilepsy. What separates epilepsy from seizures is that one who has epilepsy typically has frequent states of unprovoked seizures, rather than an occasional seizure. Epileptic subjects typically have structurally different brains than neurotypicals which is one of the main causes of epilepsy. For example, the ionic regulating systems or synaptic potentials may be affected, but there are many systems that may be afflicted in the epileptic brain. This may lead to several different manifestations of the disorder.
Epileptic episodes are typically preceded by an “aura” which signals the start of a seizure. The precise nature of these are numerous and vary from person to person, but they include hallucinations or disturbances of the senses, migraines, a feeling of dissociation, déjà vu, and other malfunctions of the brain. These lead to seizures, which are defined as “period[s] of abnormal, synchronous excitation of a neuronal population”. There are many types of seizures, such as partial seizures, generalized seizures, petit mal seizures, and grand mal seizures.
Unfortunately, epilepsy presents itself in many different forms. Thus many forms of epilepsy result in varying treatments. The patient’s age plays a vital role in proper treatment, as well as overall health, medical history, and the frequency of seizures to determine which treatment is the best. The main types of treatments for seizures include medications, surgery, and therapies. The therapies include vagus nerve stimulation (VNS), ketogenic diet, and deep brain stimulation.
Vagus nerve stimulation (VNS) is one of the most common treatments for people over age 12 who have partial seizures that are not controlled by other methods. This method can control the seizure by sending small pulses of energy to the brain from the vagus nerve (a large nerve in the neck).
Many recent innovations in the field of neuroscience and neurotechnology have the potential to treat epilepsy, such as brain-computer interfaces (BCI’s). BCI’s allow individuals to direct electrical activity using neuronal activity or internal mental processes. Many anticipate that this will allow people with severe motor defects to regain access to their bodies, but it may also be applied to epilepsy. Techniques to predict and detect seizures are currently being studied. These techniques look to present a non-invasive method to isolate seizures as opposed to electrode stimulation or drugs which have many harmful side-effects. Interestingly, one-third of epileptic patients do not respond to epileptic drugs. For those who do not, brain-computer interfaces present an area of hope for a newer, safer, and more effective form of treatment. Research into BCIs is still in its early stages and will doubtlessly improve in the coming years.
One interesting BCI application is outlined in “Brain-computer interface for the epileptic seizures prediction and prevention” by Maksimenko et. al, wherein a program is described which predicts seizures and decreases their duration, sometimes by up to 72 percent. They used two types of seizure control: stimulation that is given out on a predetermined, fixed schedule (“open-loop”) or stimulation that occurs in response to seizure detection (“closed-loop”). The Responsive Neurotransmitter (RNS) by Neuropace Inc. used closed-loop stimulation in the form of implanted electrodes which used data from an intracranial EEG for an algorithm that predicted when the seizure would start.
Epilepsy is a common brain condition that is not well understood and has several underlying causes resulting in a variety of different forms of the disease. The traditional treatments of epilepsy include medication, vagus nerve stimulation (VNS), and surgery. Recent innovations in neurotechnology attempt to apply brain-computer interfaces to root out what causes seizures and how it leads to the development of epilepsy. The evolution of neurotechnology has great potential to lead to great progress in the knowledge of seizures.
References
Sacks, O. 2012. Hallucinations
Scharfman H. The Neurobiology of Epilepsy. Curr Neurol Neurosci Rep. 2007 Jul; 7(4): 348–354.
https://www.frontiersin.org/articles/10.3389/fnins.2019.00191/full
https://ieeexplore.ieee.org/document/9061655
C. (2020, August 18). Epilepsy and Seizures. Retrieved October 27, 2020, from https://www.columbianeurology.org/neurology/staywell/epilepsy-and-seizures
