Epilepsy is a neurological condition characterized by recurring, unpredictable seizures that can affect various aspects of a person’s life, such as safety, relationships, and work. While medications are the first line of treatment, approximately 30% of individuals have drug-resistant epilepsy, drawing attention to the vital need for alternative therapies. This is where epilepsy devices come into play.
Epilepsy devices have been developed to provide those afflicted with an additional tool for managing their condition. These devices work differently than medication, mainly by disrupting the abnormal electrical activity in the brain that leads to seizures.
The hope is that by using an epilepsy device either as an adjunct or an alternative to drug treatment, individuals with epilepsy may achieve better seizure control, ultimately improving their quality of life.
How Medical Devices Can Help in Epilepsy Management?
Over the years, the approach to managing epilepsy has seen significant progress, particularly with the development of devices for epilepsy. Traditionally, anti-epileptic drugs (AEDs) were the go-to solution for controlling seizures. However, while AEDs offer relief for most patients, they aren’t always effective.
Approximately one-third of individuals diagnosed with epilepsy continue to experience seizures despite medication. Technological advancements and extensive research have led to the development of innovative seizure devices, designed to either predict, detect, or respond to oncoming seizures.
Seizure devices have transformed, evolving to become more effective, streamlined, and patient-friendly. Earlier versions of these devices were mainly focused on immediate seizure control with limited capabilities in terms of prediction and detection.
Contemporary devices, however, include features like:
- Seizure forecasting
- Real-time monitoring
- Automatic response systems
Furthermore, thanks to advancements in technology, device sizes have noticeably decreased, making them less intrusive and more comfortable for patients. Today, these devices not only aim to manage epilepsy but also work diligently to improve patients’ quality of life.
Advancements in Epilepsy Management Devices
Predict Seizures
The first notable advancement in the evolution of epilepsy management devices is their ability to predict seizures. This feature has proven revolutionary, allowing patients and caregivers to prepare for a seizure before it occurs. By analyzing patterns in brain activity, these devices can alert users of an impending seizure.
Monitor Vitals
Another significant development is the improvement in detection capabilities. Modern devices are equipped with sensors that continuously monitor physiological changes associated with seizures such as heart rate variability or abnormal movement patterns. When any unusual activity is detected, the device triggers an alarm system to alert both patient and caregiver.
Automatic Response Systems
Automatic response systems represent another major leap forward in epilepsy management technology. Some contemporary devices are designed not only to detect seizures but also to respond immediately by delivering electrical stimulation or medication directly into the brain.
Comfortable
In addition to enhanced functionality, modern epilepsy management devices have seen considerable improvements in terms of size and comfortability. Earlier models were often bulky and uncomfortable for patients; however, technological advancements have led to significantly smaller designs that are less intrusive and more comfortable for long-term use.
Improve Quality of Life
Finally, today’s advanced epilepsy management tools aim at improving the overall quality of life for individuals living with this condition. They offer features like data logging which allows physicians to track seizure frequency and adjust treatment plans accordingly; sleep monitoring which helps identify potential triggers related to sleep pattern disruptions; mood tracking.
This aids in identifying mental health concerns common among individuals diagnosed with epilepsy; along with connectivity options enabling remote monitoring by healthcare professionals.
Types of Implantable Epilepsy Devices: An Overview
Various types of implantable devices have been developed in response to the growing need for effective epilepsy management. These devices, often referred to as seizure devices, are designed to detect abnormal brain activity before it develops into a seizure.
They intervene by delivering a dose of electrical stimulation to disrupt the unusual patterns of brain activity that typically precede a seizure, resulting in a decrease in seizure frequency in many patients.
Apart from their therapeutic action, seizure devices are also equipped with data recording capabilities. They document the patient’s seizure history, providing medical professionals with invaluable insights into the progression of the disease.
Such information can lead to improved personalization of treatment methods that adhere to each patient’s unique condition. Implantable seizure devices continue to represent a significant breakthrough in the field of epilepsy management, offering hope for those who are grappling with this often debilitating neurological condition.
Neuromodulation Devices for Epilepsy
Since 1997, the Food and Drug Administration (FDA) has approved Vagus Nerve Stimulation (VNS) as an effective treatment for individuals suffering from medically refractory epilepsy. In this procedure, leads are surgically implanted around the left vagus nerve and connected to a generator placed under the patient’s skin, specifically below the left clavicle.
This generator emits electrical impulses, which modulate the vagus nerve. Although the exact mechanism of action of VNS remains uncertain, research in animal models suggests that it may influence noradrenaline release from the locus coeruleus or alter blood flow and metabolism in various brain regions, including the thalamus.
Following the surgical implantation, the device’s settings are adjusted in an outpatient setting by the patient’s epileptologist. The device can be easily assessed and reprogrammed wirelessly in the office, allowing for customization of parameters such as frequency, output current, pulse width, signal-on time, signal-off time, and magnet settings. Patients or their caregivers are provided with a magnet that they can use to activate the VNS in case of an aura or seizure.
Newer versions even permit programming to respond to a rapid increase in heart rate, often observed at the onset of a seizure. Long-term follow-up studies have demonstrated responder rates of 37% at year 1 and 43% at years 2 and 3, with a consistent trend of improved seizure control observed 18 months to 2 years after VNS implantation.
Limitations
- VNS implantation carries relatively low intraoperative surgical risks. Possible risks include local site infection and implant-site pain.
- The most common side effect is overstimulation of the VNS, resulting in temporary vocal hoarseness, coughing, and throat discomfort. These symptoms can be alleviated by adjusting the stimulation settings.
- The battery life of the VNS device is typically around 10 years, depending on settings, before requiring surgical replacement. Obstructive sleep apnea has been reported as a potential complication of VNS.
In 2018, the FDA approved Deep Brain Stimulation (DBS) as a treatment for medically refractory epilepsy. DBS involves delivering electrical stimulation to the anterior nucleus of the thalamus (ANT).
In the initial SANTE trial, which provided evidence for DBS as early as 2005, patients aged 18 to 65 with partial seizures (with or without secondary generalization), failed trials of at least three different antiepileptic drugs (AEDs), and a minimum of six seizures per month were assessed in a prospective randomized double-blind study. Similar to VNS, the response rate in the SANTE trial was 40.5%, with continued improvement observed over two years.
The mechanism of action of DBS remains uncertain, and there is ongoing debate about whether DBS has an inhibitory or excitatory effect on the thalamus.
DBS implantation is more complex than VNS, involving burr holes in the skull, advanced imaging, and both stereotactic and functional neurosurgery. DBS electrodes are implanted bilaterally in the ANT and connected subcutaneously to a generator implanted in the left chest wall. As with VNS, DBS programming is conducted wirelessly in the outpatient setting by the patient’s epileptologist.
Limitations:
As with any surgical procedure, there are potential risks during DBS implantation, including
- Intraoperative death, infection, or hemorrhages
- Common complications include paresthesia, lead repositioning, and superficial site infections
- Hemorrhages, if they occur, are often asymptomatic.
However, the risk is relatively low due to the increasing popularity and familiarity with DBS surgery. Other possible complications include status epilepticus, sudden death, and neuropsychiatric issues like Kluver-Bucy syndrome.
Approved by the FDA in 2013 as an adjunctive treatment for medically refractory epilepsy, Responsive Neurostimulation (RNS) involves the intracranial implantation of a device with two leads. This device can both record intracranial electrical activity and provide dynamic electrical stimulation to prevent seizure progression.
Utilizing closed-loop stimulation, the device detects seizure activity in the brain by monitoring electrocorticographic activity and intervenes directly at the seizure focus to halt seizure propagation. Precise localization of the epileptogenic zone is crucial for proper lead placement. Like VNS and DBS, RNS trials have demonstrated a similar pattern of efficacy, with a significant reduction in seizures in the active group during the pivotal clinical trial and ongoing improvement over time.
Limitations
Complications associated with RNS include
- Implant site infection, implant site pain
- Seizures
- Deteriorating memory
- Headaches.
- Intracranial hemorrhage and the risk of death are possible but relatively rare.
Most observed side effects are mild and self-limited.
Conclusion
Seizure devices are rapidly becoming a crucial lifeline for epilepsy patients, instrumental in controlling the severity and frequency of seizures. These implantable devices act as a form of electronic medication, delivering electrical pulses to the brain when abnormal activity indicative of a seizure is detected.
Unlike prescribed drugs, they provide a direct intervention, mitigating the effects of epilepsy at the source. As such, their precision reduces the risk of side effects common with broad-spectrum epilepsy medications, enhancing the overall quality of life for many patients.
References
- https://www.epilepsy.com/treatment/devices
- https://www.epilepsyfoundationmn.org/resource/treatment-options-implant-devices/
- https://practicalneurology.com/articles/2018-nov-dec/epilepsy-essentials-neuromodulation-devices-for-epilepsy
- https://www.ucsfhealth.org/treatments/responsive-neurostimulation
