Deep brain stimulation involves implanting electrodes within certain areas of your brain. These electrodes produce electrical impulses that regulate abnormal impulses. Or, the electrical impulses can affect certain cells and chemicals within the brain.
The amount of stimulation in deep brain stimulation is controlled by a pacemaker-like device placed under the skin in your upper chest. A wire that travels under your skin connects this device to the electrodes in your brain.
Deep brain stimulation is used to treat a number of neurological conditions, such as:
- Essential tremor
- Parkinson's disease
- Dystonia
Deep brain stimulation is also being studied as an experimental treatment for major depression, stroke recovery, addiction, obsessive compulsive disorder and dementia.
Deep Brain Stimulation (DBS) is an established treatment for movement disorders, such as Essential Tremor, Parkinson's Disease and Dystonia, and more recently, Obsessive Compulsive Disorder. This treatment is reserved for people who aren't able to get control of their symptoms with medications.
The time to consider Deep Brain Stimulation (DBS) surgery is when quality of life is no longer acceptable on optimal medical therapy as administered by a movement disorders neurologist. Deep Brain Stimulation (DBS) involves creating small holes in the skull to implant the electrodes, and surgery to implant the device that contains the batteries under the skin in the chest.
The major risks are a 1% risk of stroke causing a permanent deficit, due to bleeding in the brain, and a 2-5% chance of infection. DBS is a relatively complex therapy that requires regular neurological follow-up and battery changes every 3-4 years.
Contrary to popular belief, patients with implanted DBS systems can have MRIs if needed. All DBS patients can undergo a brain MRI as long as certain precautions are taken. Most patients that were implanted with a DBS within the last five years are able to have full-body MRIs. The MRI should be performed in a center with experience scanning patients with DBS systems.
Parkinson Disease
DBS surgery offers important symptomatic relief in patients with moderate disability from Parkinson's disease who still retain some benefit from antiparkinsonian medications and who are cognitively intact. Patients who fluctuate between "ON” and “OFF” medication states are usually good surgical candidates, as are those who have troublesome dyskinesias.
Dystonia
DBS surgery does not cure dystonia but can decrease the abnormal movements and postures of dystonia. The degree of benefit appears to vary with both the type of dystonia and the duration of the symptoms. Adolescents and young adults with inherited forms of primary dystonia appear to get very significant benefit. For patients with secondary dystonia due to stroke or head trauma, the benefit may be milder but still potentially worthwhile for improving quality of life. Adults who have had dystonia for many years probably have less improvement than those with more recent onset of symptoms.
Essential Tremor
DBS is a highly effective therapy for patients with essential tremor, often resulting in an 80% decrease in tremor that lasts for several years. Patients with a tremor secondary to stroke, traumatic brain injury or multiple sclerosis are less likely to benefit from DBS, but may still be surgical candidates if expectations are realistic.
Anyone who would get significant benefit from the treatment and can undergo the operation with minimal risk. It is not necessary to suffer for years after diagnosis with a movement disorder, trying every known combination of medicine, before DBS can be considered. DBS is a surgical option that is known to improve quality of life for movement disorder patients, so when one’s quality of life is dramatically affected by the disease or by medication side effects, it’s time to consider DBS.
DBS surgery involves placing a thin metal electrode (about the diameter of a piece of spaghetti) into one of several possible brain targets and attaching it to a computerized pulse generator, which is implanted under the skin in the chest below the collarbone. All parts of the stimulator system are internal; there are no wires coming out through the skin. A programming computer held next to the skin over the pulse generator is used during routine office visits to adjust the settings for optimal symptom control. Unlike older lesioning procedures or gamma knife radiosurgery, DBS does not destroy brain tissue. Instead, it reversibly alters the abnormal function of the brain tissue in the region of the stimulating electrode. It is important to note that DBS therapy may demand considerable time and patience before its effects are optimized.
DBS is not a cure for movement disorders, but it can successfully treat symptoms by disrupting the abnormal patterns of brain activity that become prominent in these diseases. DBS is often described as a brain “pacemaker” because constant pulses of electrical charge are delivered at settings that are thought to restore normal brain rhythms, allowing the restoration of more normal movements. The exact mechanisms of this neuromodulation are still unknown.
• Awake Microelectrode-guided DBS
The basic surgical method is called frame-based stereotaxis, which is the traditional method for approaching deep brain targets though a small skull opening.
A rigid frame is attached to the patient's head just before surgery, after the skin is anesthetized with local anesthetic. A brain imaging study is obtained with the frame in place. The images of the brain and frame are used to calculate the position of the desired brain target and guide instruments to that target with minimal trauma to the brain.
• Asleep Interventional-MRI-guided (iMRI) DBS
This is a procedure that allows DBS electrodes to be implanted with the patient asleep in an MRI scanner instead of awake in the operating room.
• Gamma Knife Surgery
For patients that are not candidates for awake or asleep-DBS, Gamma Knife surgery may be used to create a thalamotomy (lesion of the thalamus) for the management of tremor. The tremor can be from essential tremor, Parkinson’s disease or multiple sclerosis. Gamma knife radiosurgery is mainly performed in patients who have medical risks that make open surgery hazardous or those with very advanced age.