What is Deep Brain Stimulation for Parkinson’s disease?
Deep Brain Stimulation (DBS) means the electrical stimulation of the brain by using a small machine.
This small machine is inserted below the skin of the chest. Two small wires from this machine go upwards. They are then precisely inserted into small holes in your skull. Then they reach specific parts of your brain – such as the “Subthalamic nucleus” or the “Globus Pallidus Interna”.
How much does Deep Brain Stimulation (DBS) cost in India?
Depending on the device that is used, Deep Brain Stimulation for Parkinson’s Disease can cost between 8 lakh to 15 lakh rupees.
Battery replacement is cheaper, around 2-4 lakh rupees.
What are the indications for Deep Brain Stimulation (DBS)?
Deep Brain Stimulation is offered to patients whose symptoms are not well controlled with medications. It is approved for use in the following diseases:
1) Parkinson’s disease
2) Essential Tremor
3) Primary Dystonia
Here, we will only be talking about it’s use in Parkinson’s disease.
As Parkinson’s disease progresses, it becomes more and more difficult to satisfactorily control symptoms with medications alone. At one point, additional help is needed. The two most common scenarios are:
- Early wearing off of levodopa – If the patient complains that the effect of levodopa lasts only for 30 minutes, or that this duration is so short that he/she is unable to do anything meaningful during that time. Frequently, these are patients who are taking levodopa 5 or 6 times in a single day.
- Excessive dyskinesias – If treatment with levodopa becomes difficult because taking it causes excessive shaking, then the DBS procedure can reduce this shaking. This enables a sufficient quantity of levodopa can be taken.
How does Deep Brain Stimulation (DBS) work?
No one completely understands how Deep Brain Stimulation (DBS) works.
Deep Brain Stimulation (DBS) was invented after a series of experiments in which small parts of the brain were made dysfunctional. Thi surgery – destroying small parts of the brain (e.g. Thalamo-tomy, Pallido-tomy: “tomy” means “to cut”)
While destroying these parts of the brain, surgeons noticed that whenever they applied a high frequency electrical current, the tremor of Parkinson’s disappeared! How wonderful would it be if this current could be made permanent! Then there would be no need to destroy any part of the brain! This led to the design of the DBS electrical system around 2000, and it was approved for use in 2002.
Therefore, it is a truly empirical device. Many researchers believe it causes the structure it is inserted into to become dysfunctional. A few researchers believe that it causes the target structure to become hyperactive.
The reality is that each of these target structures – e.g. the subthalamic nucleus – contain many thousands of little cells arranged in very intricate circuits. Probably, some of these cells become dysfunctional, while some become hyperactive. The number and types of cells that have these varying effects is probably affected by the amplitude and very importantly – the frequency of the current that is applied.
Regardless of the effect of DBS on the target structure, it is clear that it has a beneficial effect overall on the circuits regulating movement. The most important part about DBS is that it works, as described in the next answer.
Is Deep Brain Stimulation (DBS) effective?
Deep Brain Stimulation for Parkinson’s Disease is very effective. It has an extremely good – though not magical effect – on the symptoms of Parkinson’s disease.
The following are the benefits of Deep Brain Stimulation for Parkinson’s Disease:
1) It acts almost immediately. This immediate effect is due to the surgery itself and gradually decreases over the next few weeks. The current is switched on about 4 weeks later, leading to sustained improvement.
2) On average, it gives the patients about 4 to 6 excellent hours per day, in ADDITION to the ones the patient is getting. After the surgery, patients have an average of 11-12 hours of excellent functioning during the day.
3) Also, the bad hours (OFF-periods) become LESS INTENSE, so that the patient able to have some function, e.g. walking even during these bad hours.
4) Stimulation of certain sites (e.g. GPi) can reduce abnormal movements (called dyskinesias – read here). This enables you to take more medications so that your symptoms are effectively controlled.
5) On the other hand, stimulation of certain sites (e.g. STN) decreases your symptoms themselves, so that the dose of your medications can gradually be reduced by about half.
6) Many patients who get DBS become functionally independent – i.e. they can take care of their daily activities such as bathing, dressing, using the toilet etc.
7) It provides very long term improvement – The beneficial effects of DBS are sustained for at least 10 years (Castrioto 2011). They may last longer, but since the device is less than 25 years old, researchers all over the world are still collecting that data.
What is STN-Deep Brain Stimulation? What is GPi-Deep Brain Stimulation? Which one is better?
In Deep Brain Stimulation for surgery, the wires inserted into the brain (electrodes) are targeted to one of the following two structures:
- The Subthalamic Nucleus (STN, or STN-DBS)
- The Globus Pallidus Interna (GPi or GPi-DBS)
Stimulation of the Subthalamic Nucleus produces relief of Parkinson’s symptoms. Therefore, post-surgery the dose of medications can be reduced. Typically, the dose of medications can be reduced by 50% or half.
Stimulation of the GPi decreases the symptoms of Parkinson’s, but to a lesser degree than STN-DBS. But, it has two additional benefits over STN-DBS:
- Firstly, it reduces a peculiar side-effect of Parkinson’s medications called Dyskinesias. Because of this, after surgery, an adequate quantity of Parkinson’s medications can be given to relieve the patient’s symptoms. Therefore, typically there is no reduction in medication dosage after GPi-DBS surgery.
- Secondly, GPi-DBS may have lesser side-effects on thinking, memory and mood as compared to STN-DBS.
STN-DBS surgery is the default choice of most centres and is the most commonly performed surgery, by far. In some people, the dyskinesias can be extremely disabling, so that the neurologist selects GPi-DBS instead. GPi-DBS may also be selected if the neurologist is very concerned about problems with your thinking, memory or mood.
Which companies manufacture Deep Brain Stimulation (DBS) systems, and what are their advantages and disadvantages?
Earlier, only Medtronic used to manufacture the Deep Brain Stimulation (DBS) system.
Subsequently, two more devices have been approved:
1) Abbott St. Jude Medical Infinity – with the ability to “steer” current towards the target.
2) Boston Scientific Vercise – with more contact points to enable precise stimulation.
Both these newer devices are, in general, more expensive than the Medtronic device.
The newer devices are particularly useful when the wire inside the head has been slightly misplaced during surgery. For example, if the target is slightly to the left of the wire – then the St. Jude device can steer the current so that it goes more to the left than to the right. In theory, this ability to steer current or to stimulate tiny parts of the brain should also cause lesser side-effects.
But, even though these newer devices attractive in principle, they have not been proven to be more effective than the Medtronic device. At this time, therefore, any of these devices is an excellent choice for DBS.
How many years does the battery of Deep Brain Stimulation (DBS) last?
Each of these devices can be connected to one of two kinds of batteries: A non-rechargeable one OR a rechargeable one.
The non-rechargeable batteries are cheaper. However, overall they last for a shorter period before needing the battery to be replaced. The battery replacement surgery is much smaller and quicker, only the battery in the skin below the chest is replaced. There is no need to touch the brain at all.
The average life of each of these batteries is noted below. Please note that the wires inside the head do not need replacement – it is only the battery below the chest skin which is quickly replaced.
|Model Number||Average life span (years)|
|Medtronic Activa||Activa – PC||3 to 5|
|Abbott St. Jude||Infinity 7||4 to 5|
|Boston Scientific Vercise||Vercise – PC||3|
|Model Number||Average life span (years)|
|Medtronic Activa||Activa – RC||15|
|Abbott St. Jude||Infinity 7||15|
|Boston Scientific Vercise||Gevia||25|
Dr. Siddharth Kharkar
Dr. Kharkar is a Neurologist, Epilepsy specialist & Parkinson’s disease specialist in Mumbai, Maharashtra, India. He has trained in the best institutions in India, US and UK including KEM hospital in Mumbai, Johns Hopkins University in Baltimore, University of California at San Francisco (UCSF), USA & Kings College in London.