Epilepsy is a brain disorder in which the primary symptom is the experience of seizures. In a seizure a cluster of neurons in the brain begins to signal abnormally; frequently this involves a synchronous pattern of ﬁring by cells that would not normally be ﬁring in unison. This disturbed pattern of neuronal activity creates a variety of symptoms, including, but not limited to, odd sensations, emotional states, and behaviors; as well as, in the more serious seizures, convulsions, muscle spasms, and loss of consciousness.
The major convulsive seizures are sometimes called grand mal (French for big bad) seizures; the small ones, petit mal. A seizure can be caused by anything that disrupts the usual pattern of brain activity, including drugs, brain damage, abnormal brain development, fever, or altered levels of neurotransmitters. Simply having a seizure does not mean that a person has epilepsy. Only when a person has had two or more seizures is a diagnosis of epilepsy made. PET scans and fMRI have made diagnosis of epilepsy far more precise than it used to be.
Modern treatment of epilepsy usually involves drugs, which are effective in controlling seizures in about 80 percent of cases. Brain surgery was far more common as a treatment in the past, prior to the advent of better drugs; and now when surgery is done, it is much less invasive than some of the past procedures, which included completely severing the connection between the hemispheres.
For those patients whose epilepsy hasn’t responded well to drugs, another treatment has recently become available. In 1997 the FDA (Food and Drug Administration) approved an electronic device called the vagus nerve stimulator (VNS) for use in epileptic patients. About the size and shape of a thin hockey puck, the VNS is implanted in the chest and connected to the vagus nerve, one of the major nerves that allows the brain to communicate with various parts of the body. The VNS works by periodically stimulating the vagus nerve. How it achieves an anti-epileptic effect is unclear, but it may be that it interrupts the production of the synchronous discharges that create seizures, scrambling them before they can become seizure activity. Since some people with epilepsy can feel when a seizure is about to start, the device can be programmed with a special sequence of impulses that can abort a seizure before it really gets going. This function can be activated by passing a magnet over the VNS. For patients who can’t detect an impending seizure, this function can allow caretakers to shorten the seizure. This device has allowed many patients to reduce their medication and improve their quality of life, both by preventing seizures and by signiﬁcantly reducing their recovery time after a seizure.
Some patients have also been helped by a ketogenic diet, which is extremely low in carbohydrates and high in fat. This is actually similar to the low-carb diets that are popular for weight loss, except that protein intake is also restricted. How the diet helps is unclear, but it may alter levels of various neurotransmitters, including GABA (gamma-aminobutyric acid), which is known to be involved in some seizure activity.
- Kossof, E. H., and Pyzik, P. L. “Improvement in Alertness and Behavior in Children Treated with Combination Topiramate and Vagus Nerve Stimulation.” Epilepsy & Behavior, 5(2) (2004): 256–259.