A brain implant will get rid of epileptic seizures
Approximately 30-50 percent of epileptics fail to prevent seizures with medication, which forces hundreds of thousands of patients to live in constant tension and expectation of an unpredictable seizure. In some cases, surgical surgery helps to remove the area of the brain in which abnormal nerve impulses are generated, causing epileptic seizures. But this option is not always possible either: the centers of abnormal activity may be localized in the parts of the brain responsible for speech or vision, and in this case surgical intervention is excluded.
The device proposed by the Californian company Neuropace is called a "Responsive Neurostimulator" and is one of a small number of electrical stimulation devices developed for epileptics known today. The effect of devices of this kind is to contain an uncontrolled storm of nerve impulses during a seizure with the help of electrical discharges from an external source.
Unlike similar devices that stimulate the nervous system continuously or according to a programmed schedule, the unique Neuropace implant scheme allows you to monitor brain activity and send electrical impulses only when abnormal activity is detected, foreshadowing the onset of a seizure. This approach is like extinguishing a spark before it turns into a flame.
The Neuropace implant consists of a neurostimulator, no larger than a deck of cards, which is surgically implanted from the outside of the skull along with a set of electrical wires designed to register brain activity and supply an electric discharge. Wires are laid either on the surface or deep into the brain tissue, depending on which department is the source of seizures. Before the operation, the surgeon localizes the "convulsive focus" based on computed tomography and electroencephalography data, as well as measuring brain activity directly from the surface of the cerebral cortex using electrocorticography.
The device also includes a battery and a miniature computer that constantly monitors the electrical activity of the brain. As soon as its amplitude increases, the program recognizes this as an emergency event and sends an electrical impulse to the brain. The system then re-analyzes brain activity and determines whether further stimulation is necessary.
In clinical trials involving 200 epileptic patients who could not be treated with at least two medications, an electrostimulating device led to a 29% decrease in the frequency of seizures, compared with 14% in the placebo group with an implanted but not switched on device. Almost half of the patients who received the implant showed a significant decrease in the frequency of seizures.
Although the results obtained may seem very modest, it should be noted that the study participants suffered from severe forms of epilepsy. They had seizures at least three times a month, and many more often. Most of the patients suffered from epilepsy for at least 20 years and took several medications that prevent the occurrence of seizures. A third of the participants also turned to vagus nerve stimulation, and another third underwent surgical treatment.
Implantation of an electrostimulating device into the brain looks fantastic for some, but for others it seems too serious an intervention and an encroachment on nature. But patients suffering from severe forms of epilepsy are so exhausted by its unpredictable manifestations that they agree to any remedy that can stop seizures. For patients who have unsuccessfully tested all means, even the modest achievements of Neuropace are very significant.
Clinical studies have also shown that both the implantation procedure and the device itself are safe enough, only a few patients had minor infection or bleeding. In addition, none of the participants had memory disorders or depression. Despite the fact that the method requires surgical intervention, the obvious advantage is the absence of side effects characteristic of drug treatment (drowsiness, double vision).
The disadvantage of the Neuropace device is the difficulty in application. After the operation, the patient must undergo an optimization period during which the stimulator is programmed to recognize specific patterns of characteristics of electrical activity of the brain) preceding the seizure and the reproduction of a certain electrical impulse. The doctor analyzes the information received from the implant and can adjust and adjust it according to the individual nature of the patient's course of illness.
Since the Neuropace device is quite new, the researchers are confident that the accumulation of information about its operation in each individual case will undoubtedly contribute to its improvement and increase efficiency. For example, in the course of clinical trials, scientists learned that the maximum effectiveness of the stimulating pattern is determined by the point at which an epileptic seizure originates. In most of the study participants, the epileptic focus was localized in the hippocampus, but in some, the foci of abnormal activity were located in separate areas of the cerebral cortex, or in both areas simultaneously. Brain monitoring using the Neuropace device helped to establish that epileptics with convulsive foci in the hippocampus perceive high-frequency stimulation better, while foci in the cerebral cortex respond more effectively to lower frequencies.
Neurophysiologists also welcome the appearance of a new device, as it will allow us to better understand the mechanism of epilepsy. For example, researchers will be able to determine whether the patterns preceding the onset of an epileptic seizure change over time, or identify certain factors that can predict the outcome of an attack. Before, it was not possible to get answers to these questions.
Ruslan Kushnir
Eternal Youth Portal www.vechnayamolodost.ru based on Technology Review: Brain Implant Cuts Seizures15.12.2009