Deep Brain Stimulation (DBS)
Deep Brain Stimulation (DBS) is a surgical intervention used to treat various neurological disorders by implanting electrodes in specific areas of the brain. This procedure aims to modulate abnormal electrical activity or influence neurochemical production, helping manage conditions such as Parkinson's disease, epilepsy, and Tourette syndrome. The electrodes connect to an implantable pulse generator, which is surgically placed in the patient's chest, allowing them to control stimulation levels. The procedure typically occurs in two phases: the first involves placing the electrodes while the patient is awake for feedback, and the second involves general anesthesia for the generator placement.
Historically, the concept of using electrical stimulation on the brain dates back to ancient Rome, with significant advancements made in the mid-20th century. DBS is particularly effective for Parkinson's disease, targeting the basal ganglia to alleviate symptoms like tremors and movement difficulties. However, it is generally considered for patients with advanced stages of the disease when medications are insufficient. While beneficial effects include improved quality of life and reduced medication dependency, risks such as infection, speech impairment, and mood changes must be carefully weighed. Overall, DBS represents a promising option for individuals suffering from chronic neurological conditions, though its application remains a carefully considered choice in medical practice.
Deep Brain Stimulation (DBS)
Deep brain stimulation is a surgical procedure in which electrodes are implanted in a patient's brain to facilitate control of abnormal electrical activity. Alternately, the electrodes can be deployed to regulate the production of certain neurochemicals or affect targeted cellular structures to manage a disease or chronic condition. The degree of stimulation generated by the electrodes is controlled by a device known as an implantable pulse generator, which is surgically inserted in the patient's chest region and connected to the electrodes with a network of wires. The patient then uses the implantable pulse generator to control the amount of electrical stimulation the brain receives.
History and Development
Humans have been aware of the links between electricity and brain function for thousands of years. Historical evidence shows that electrical stimulation has been used to modulate the brain since the time of the Roman Empire. Text dating to the year 46 C.E. shows that the physician of the Roman emperor Claudius endorsed the placement of the electric ray, a fish that naturally generates its own electricity, on the emperor's head as a treatment for headaches.
During the twentieth century, researchers discovered that the electrical stimulation of deep regions of the brain held promise as a treatment for the tremors and involuntary movements caused by Parkinson's disease. The technique of implanting electrodes in the brain to regulate cerebral electrical activity was first proposed by the Spanish neuroscientist José M. Delgado in 1952. In 1963, Delgado conducted a famous experiment in which he used a remotely controlled electrical implant to stop an angry bull from charging. By the end of the 1960s, Delgado had implanted electrical devices into the brains of twenty-five human patients, with varying degrees of success.
Research into deep brain stimulation continued, and scientists focused on its promising applications in the treatment of movement disorders and chronic pain. With vast improvements to the safety and reliability of the implantation procedure, the United States Food and Drug Administration (FDA) approved deep brain stimulation surgery in 1989. While it has since fallen out of favor as an option for pain management, deep brain stimulation has found new applications.
Medical Applications
Deep brain stimulation is primarily used to treat neurological diseases and conditions, including epilepsy, Parkinson's disease, and Tourette syndrome. Some clinicians continue to advocate it as a treatment for chronic pain, and it can also be used to manage extreme cases of obsessive-compulsive disorder. Currently, deep brain stimulation is considered an experimental option for treating dementia, major depressive disorders, and substance abuse, all of which are believed to be linked to brain activity that can be altered by direct electrical stimulation. Potential stroke recovery applications are also being studied.
The surgery takes place in two phases. During the first phase, the electrodes are implanted in the patient's brain, and wires leading into the chest are put in place. The patient remains awake during this portion of the surgery, allowing him or her to supply direct feedback that helps the surgeon optimize the placement of the electrodes. The second phase of the surgery involves the placement of the implantable pulse generator, which is usually positioned in the patient's upper chest, just below his or her collarbone. This phase of the procedure is typically performed with the patient under general anesthesia.
Deep Brain Stimulation and Parkinson's Disease
The management of Parkinson's disease is one of the primary applications of deep brain stimulation. It is clinically proven to help patients manage some of the more intrusive and troublesome symptoms, including tremors, delayed movement, and walking difficulties. However, it is only offered as a treatment option to patients with progressed cases of Parkinson's disease with symptoms that can no longer be managed with medication.
Patients with Parkinson's disease exhibit either too much or too little electrical activity in the brain system known as the basal ganglia. The basal ganglia plays a major role in regulating the feedback loops and brain circuitry that affect movement and coordination. Deep brain stimulation for Parkinson's disease usually targets a region of the brain known as the subthalamic nucleus, which controls the action-selection mechanisms that control bodily movements.
Risks and Benefits
As with all surgical procedures, deep brain stimulation poses some risks to the patient's health, and these risks must be weighed against the potential benefits. General risks include infection, bleeding, the formation of blood clots, and an adverse reaction to the anesthetics used to numb affected areas of the patient's body during the procedure. Approximately 1 percent of deep brain stimulation patients experience continued bleeding in the brain after surgery, causing serious complications.
In some Parkinson's disease patients, deep brain stimulation can cause or intensify speech impairment and balance difficulties, and some people experience mood disorders after the surgery. Doctors can make programming adjustments to help alleviate these symptoms, but in some cases, the risks and drawbacks outweigh the benefits. In these instances, the patient can elect to turn off the electrodes or have them removed altogether.
Immediately following surgery, some patients experience side effects that include seizures, headaches, and confusion. Mood changes, speech and balance difficulties, lightheadedness, tightening of the muscles in the face and/or arms, tingling sensations, and numbness can also occur during and after the stimulation of the implanted electrodes. Deep brain stimulation surgery is also believed to increase the patient's subsequent risk of suffering a stroke. The procedure is only considered once all other treatment options have been exhausted.
Beyond helping the patient achieve control over difficult to manage symptoms, deep brain stimulation has also been reported to improve sleep and boost the overall quality of life in qualified patients. Electrodes must be precisely placed in correctly chosen regions of the brain to achieve optimal results. In patients with Parkinson's disease, deep brain stimulation usually results in a decreased reliance on medication.
Bibliography
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