Epilepsy is a neurological condition characterized by recurrent, unprovoked seizures, which are sudden bursts of abnormal electrical activity in the brain. Focal epilepsy is a common type where seizures originate in a specific, localized area. Many individuals with focal epilepsy wonder about a “cure” for their condition.
What is Focal Epilepsy?
Focal epilepsy, also known as partial or localization-related epilepsy, involves seizures that begin in a limited network of neurons within one hemisphere of the brain. This differs from generalized epilepsy, where seizures rapidly engage widespread networks in both sides of the brain simultaneously. Focal epilepsy is the most common type of adult-onset epilepsy.
The causes of focal epilepsy can vary, sometimes stemming from identifiable brain injuries, strokes, tumors, or infections. Genetic factors can also play a role, and in many instances, the specific cause remains unknown. Symptoms of focal seizures depend on the brain region affected and can include changes in sensations, emotions, or muscle movements.
Focal seizures are categorized based on awareness during the event. Focal aware seizures, previously called simple partial seizures, occur when an individual remains conscious and aware of their surroundings throughout the seizure. Focal impaired awareness seizures, formerly known as complex partial seizures, involve a change or loss of consciousness, often characterized by staring or repetitive movements like lip-smacking or hand rubbing. These seizures can sometimes spread to affect both hemispheres of the brain, leading to a focal to bilateral tonic-clonic seizure.
Treatment Approaches for Seizure Control
The primary approach to managing focal epilepsy involves anti-seizure medications (ASMs), which aim to prevent seizures. Finding the right medication and dosage often requires careful adjustment to achieve optimal seizure control with minimal side effects.
When seizures are not adequately controlled by medication, a condition referred to as medically refractory epilepsy, other treatment options become available. Epilepsy surgery is a consideration for some individuals, where the goal is to remove the specific brain area generating the seizures. This approach is typically considered when the seizure-originating area can be precisely identified and safely resected without causing significant neurological deficits.
Neuromodulation Devices
Neuromodulation devices offer additional possibilities for seizure reduction. Vagus Nerve Stimulation (VNS) involves implanting a device that sends electrical pulses to the brain via the vagus nerve in the neck, helping to reduce seizure frequency and severity.
Responsive Neurostimulation (RNS) is another implanted device that continuously monitors brain activity and delivers electrical stimulation directly to the seizure-generating area when abnormal activity is detected. Deep Brain Stimulation (DBS) involves implanting electrodes in specific brain regions to deliver electrical impulses to influence brain activity and reduce seizures. These devices are often used in conjunction with ASMs.
Dietary therapies, such as the ketogenic diet or modified Atkins diet, are also options for specific cases, particularly for individuals whose seizures are not well-controlled by medication. These high-fat, low-carbohydrate diets aim to induce a metabolic state called ketosis, which can reduce seizure frequency. The modified Atkins diet is a less restrictive variation of the ketogenic diet and has shown promise in reducing seizures for some adults and adolescents.
Defining “Cure” and Achieving Remission
For most types of epilepsy, a complete “cure” in the sense of eradicating the underlying condition is uncommon. Instead, the more realistic and common goal is achieving “remission,” which signifies a prolonged period of seizure freedom. Remission is generally defined as being seizure-free for a significant duration, often several years, with some definitions specifying a period of at least 10 years without seizures, including 5 years off anti-seizure medications.
Many individuals with focal epilepsy can achieve seizure freedom. Approximately 60% to 70% of people with epilepsy achieve good seizure control with appropriate anti-seizure medications and maintain long-term remission. For those who undergo epilepsy surgery, the chances of achieving seizure freedom can be higher, with a significant percentage becoming seizure-free or experiencing a substantial reduction in seizure frequency. For example, studies on Responsive Neurostimulation (RNS) show median seizure reductions of 75% after nine years of treatment.
Achieving remission means living a life free from seizures, which can significantly improve quality of life, even if the underlying condition is not entirely reversed. Long-term seizure freedom through remission is a highly desirable and achievable outcome for many.
Factors Affecting Prognosis
Several factors influence an individual’s likelihood of achieving seizure control or long-term remission in focal epilepsy. A better prognosis is associated with an identifiable cause that can be treated, such as a resectable brain lesion. Early diagnosis and prompt treatment also contribute to more favorable outcomes. Individuals without significant underlying structural brain abnormalities or other neurological conditions tend to respond better to treatment. A positive response to initial anti-seizure medications is also a good indicator for a better prognosis.
Conversely, certain factors can make achieving seizure control more challenging. The presence of significant structural brain abnormalities can lead to a less favorable prognosis. A long duration of epilepsy before treatment may also make it harder to achieve seizure freedom.
Individuals experiencing multiple seizure types or who do not respond to several anti-seizure medications may also face a more complex treatment journey. Co-existing neurological or developmental conditions can impact the overall prognosis.