Deep brain stimulation is an elective procedure that involves implanting electrodes in specific parts of the patient’s brain. These leads or electrodes produce electrical impulses that further help in controlling irregular brain activity. This includes chemical imbalances occurring in the brain that can lead to various medical conditions. Such brain stimulations are controlled by a device. This is a programmable generator or pacemaker device placed in the upper chest under the skin of the patient.
In 2002, US FDA approved deep brain stimulation (DBS) to treat patients suffering from Parkinson’s disease (PD). Since then, DBS is used to provide constant electrical stimulation to the abnormal areas in the brain. This pace-maker device has been used to treat 40,000 patients with essential tremors and Parkinson’s disease worldwide.
DBS is a surgical procedure used to treat movement disorders such as Parkinson’s disease, dystonia, and essential tremor. It can also be implanted to control symptoms of epilepsy and obsessive-compulsive disorder. This procedure is usually recommended when medications no longer provide any relief to the patients.
More than 1,60,000 patients suffering from various neurological conditions are being effectively treated with DBS.
Following are some of the symptoms that can be controlled with the help of DBS:
In various centres, a stereotactic frame technique is being utilised that involves fixing it to the patient’s skull. During this technique, the reference frame can be used along with a CT or MRI visible adapter. This generally depends upon the imaging modality used for aiming and for recording the images into the patient’s head. These systems also require a CT scan or MRI to be taken instantly after the frame is placed.
The process of frame placement, followed by image acquisition, calculation, and at last, translation of the coordinates for the frame can be bit time-consuming. It also increases the patients’ discomfort, and use up all valuable resources of the operating theatre room and time. The placement of frame on the patients who are awake and not taking any medications can be very challenging. Patients can find it difficult to endure the frame placement during a procedure that confines their range of motion and takes a lot of time to complete.
Frameless stereotaxy, it takes less time to complete the whole surgery. This is because imaging tests are being performed before the surgery begins so that the frame can be fixed without any delay. This further alleviates patients’ discomfort, because they can reposition themselves and move their head during the surgery. This type of system does not need any periodic recalibration of the frame. It may also target some of the back areas of the brain without inverting the frame.
Before the DBS treatment, the patient is advised to undergo various tests to carefully evaluate whether DBS is a good option for the patient or not. These tests assess the thinking and memory status of the patient. A psychiatrist may also examine the patient to determine if there is any prevailing medical condition like anxiety or depression. In which case the patient may require to be treated before going for the DBS surgery. The selection of a patient for this procedure is usually a multidisciplinary process that involves a neurosurgeon, a movement disorder neurologist and a neuropsychiatrist.
It is also important for the doctor to ask if the patient has any dietary restrictions, is taking medications or smokes, for example.
During the procedure
The neurosurgeon implants the DBS system in the following two steps:
The neurosurgeon places leads directed by the maps and images of the patient’s brain. For this part of the surgery, the patient is awake. This ensures the lead placement is done in the best location to control the movement symptoms.
For Parkinson’s disease, many of the leading centres in the world now perform this surgery with the patient asleep. This is providing that they have access to high quality MRI and the option of intraoperative accuracy confirmation such as with MRI or CT.
When it is done with the patient awake, the neurosurgeon will stimulate a brain area to test the results. This can be don by asking the patient to move their legs, or hands, tap fingers, or pretend to drink from a cup.
Under general anaesthesia, the neurostimulator is placed usually below the collar bone, under the skin of the patient.
Then the leads will be connected to the neurostimulator. This is done with the help of extensions that run beneath the skin from the patient’s chest to the head and neck.
Some side effects can be expected, but the surgery is not very painful. In the weeks and months after DBS surgery, patients may observe some side effects. This depends on the initial programming and medications involved. The side effects may be numbness, abnormal sensations, tingling, and involuntary muscle contractions. Most of the patients may also feel some degree of discomfort due to the implantation of the neurostimulator. However they get used to it over time.
The recovery period post-surgery is quite short. Many patients can return to their normal daily activities in very little time while they co-ordinate with doctors to program the device. Apart from mild pain in the initial days after treatment that can be treated with some pain-killers, patients do not experience much pain.
Subthalamic nucleus deep brain stimulation offers long-term improvements in motor function for Parkinson’s disease (PD). This does not stop the neurodegenerative processes of PD. As such, quality-of-life scores have also fallen.
Long-term outcomes of DBS are precision of electrode targeting, patient selection, medication adjustments, and experienced stimulation.
Deep brain stimulation surgery is being studied as a potential treatment for:
A new case study from the University of California, San Francisco, suggests adapting deep brain stimulation to a patient’s individual needs could relieve depression symptoms at least temporarily.
The researchers found that stimulating three specific brain areas could help induce calm, renew energy levels, or reignite pleasure in a patient with depression.
Deep brain stimulation for Parkinson’s Disease, essential tremor and dystonias are covered by medicare.
Parkinson’s disease causes uneven electrical signals in some brain areas that control movement activities. DBS utilises electrical stimulation to control these control centres deep to the surface of the brain. This enhances the communication between the brain cells. It also helps to decrease symptoms such as slowness, tremor, and stiffness.
With optimum stimulation parameters, deep brain stimulation rapidly improves anxiety and mood.
Researchers found that electrically stimulating three separate locations in the brain helps to reduce the following symptoms of depression:
DBS does not cure Parkinson’s disease or any other neurological conditions. It does reduce the symptoms and enhance the overall quality of life of the patient.
Over time as the disease progresses, the efficacy of the therapy can wane.
DBS is usually considered to be a safe and effective procedure. with all surgeries there are potential risks and side effects. In the case of DBS, any risks or side effects are generally reversible and mild.
Parkinson’s doesn’t interfere with an individual’s quality of life at the onset of the disease. At the beginning, the symptoms are also mild.
Parkinson’s continues to damage the brain at the later stages and the symptoms progress. This leads to a loss of muscle control and movement.
In Parkinson’s disease, it is suggested to have the surgery in the early stage in comparison to the later stages, so as to control the disease early.
An Earlystim study, established that deep brain stimulation as a treatment was effective as compared to other medical treatments. This is in reference to patients with Parkinson’s disease and with early motor symptoms and complications.
Yes, a research conducted on Parkinson’s patients between 2002 to 2014 established that over 3 years after DBS placement, Parkinson’s patients achieved at least a 50% reduction in dopaminergic medications and corresponding dosages.
MRIs can be performed in patients with DBS as typically MRIs do not interact with the outcomes of DBS in patients. However the patient should review the manufacturer’s guidelines to double check the impact.
For approximately 90% of patients with essential tremors, deep brain stimulation provides moderate relief. This surgery for essential tremors and other movement disorders, can reduce motor symptoms and improve your quality of life.
Battery will need to be replaced every two to five years. Some rechargeable battery based DBS system may last for up to 9 years.
During the DBS process, the programmer will use a small device to adjust the setting of the DBS system. The doctor will hold a small wand over the neurostimulator. This check the effects of the electrodes and the stimulation settings.
DBS will continue to work for patients whose symptoms are responding to dopaminergic medications. Patients with DBS have now been followed for 10 or more years, and the therapy is found to be effective in patients. DBS also works long-term against tremor and dyskinesia.
In the early stages of the complication, low-frequency DBS reduces the gait freeze and gait impairment.
Deep brain stimulation has a beneficial effect in Parkinson’s disease patients with motor fluctuation or medication refractory tremor. However, it has fewer benefits in axial symptoms of balance, speech, and swallowing function.