Introduction to Parkinson’s Disease

The brain is made up billions of cells called neurons that communicate with each other and with the rest of the body, to achieve a wide range of voluntary and involuntary activities desired by the person. Chemicals called neurotransmitters are used by the brain to control how the neurons communicate with each other. One such chemical is dopamine, the most important among all neurotransmitters.

Parkinson’s Disease (PD) is an ailment which causes a drop in dopamine levels as well as deterioration in a specific area of the brain called basal ganglia. As a result of these two developments, all those abilities controlled by this area of the brain, are deeply impacted. While movement-related symptoms are easily noticed by everybody, there are a whole lot of non-motor symptoms also. Some of the known symptoms are:

• Slowed movements (bradykinesia)
• Tremor while muscles are at rest
• Rigidity or stiffness
• Unstable posture or walking gait
• Blinking less often than usual
• Cramped or small handwriting (micrographia)
• Drooling
• Mask-like facial expression (hypomimia)
• Trouble swallowing (dysphagia)
• Unusually soft speaking voice (hypophonia)
• Orthostatic hypotension (low BP while standing up)
• Constipation and other gastrointestinal problems
• Urinary incontinence
• Sexual dysfunction
• Depression
• Loss of sense of smell (anosmia)
• Sleep related issues such as periodic limb movement disorder (PLMD), restless legs syndrome (RLS) and rapid eye movement behaviour disorder (REMBD)
• Cognitive issues – trouble in thinking clearly or focus, also called Parkinson’s-related dementia

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What is Deep Brain Simulation

Deep Brain Simulation (DBS) is a neurosurgical procedure in which electrodes are implanted in the brain to simulate, reactivate, and manipulate how certain regions of the brain work. The logic is that, neurological conditions are caused by disturbed or disorganized electrical signals that travel back and forth between neurons in the brain and other parts of the body. If an electrical device can send out small electrical signals on a continuous basis to the affected areas of the brain, some of these disturbed neuro-signals can be corrected to a significant extent.

The procedure started off as an experiment done in 1987 to treat Parkinson’s related tremors. The US Government body, FDA, approved the same in 1997. Thereafter, DBS has been used successfully to treat a range of neurological conditions other than PD such as non-PD tremors, conditions such as Meige syndrome that cause dystonia (repetitive and continuous twitching, spasms and cramps of muscles in different parts of the body), epilepsy, Tourette syndrome (repetitive movements, unwanted sounds, offensive language) and Obsessive Compulsive Disorder (OCD) which is a behavioural disorder. Its also being evaluated to treat Huntington’s Disease, obesity, chronic pain, addictions, cluster headache, depression and dementia.

In recent years, DBS is becoming increasingly popular with PD patients and their families. It comes with its own risk of complications and side-effects; and patients can never fully return to a normal, healthy life. However, the benefits outweigh the disadvantages. For example, PD patients who are undergoing DBS from a long time show marked improvement in their quality-of-life. They are able to eat and use the bathroom on their own, their quality of sleep improves, their pain and urinary urgency reduces.

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Who is a candidate for DBS?

DBS is not just as simple as implanting electrodes and being done with it. Since we are talking of manipulating areas of the brain, it has to be done very carefully. Else, there can be complications, or the desired outcome may not emerge. So, a series of investigations and evaluations of the patient, and consultations with medical teams, will be involved. The patient and his/her family members must be able to commit time for all these. So, people who live far from the hospital where DBS is offered, must factor this in the decision.

Once the electrodes are implanted, the electrical signals must be programmed and re-programmed again and again over a period of time, so that the desired outcomes are achieved. It is similar to modern-day technologies like machine learning and data sciences where the device/equipment must be ‘trained’ over time to behave in a particular way. In this case, that device is the brain. Some patients or their family members who are impatient for quick results may not be able to appreciate the rigours involved in this process.

The procedure is fairly costly in India as of now, and some insurance companies may not cover the same. These should also be factored in the decision. However, reputed hospitals like Kauvery Hospital offer the same at reasonable prices, and handhold patients’ families through all the formalities.

In short, while some patients or their families may opt out of DBS because of the above factors, most of them choose to go ahead because of the positive outcomes involved.

When it comes to the patient profile

DBS is undertaken for patients:

• Whose PD symptoms interfere with their day-to-day activities
• Whose mobility is affected or not affected depending on the medication and its dosage, irrespective of whether there is dyskinesia or not.
• Who are showing better response to PD medication compared to the past
• The patient has been given different combinations of PD medications in the past, under medical supervision.

DBS is not undertaken for patients:

• Who have difficulty with walking or balance, and suffer from “freezing” (not moving)
• Who suffer from speech difficulty
• Who have cognitive issues like confusion, memory and clarity issues
• Psychological conditions like depression or anxiety have not improved with treatment
• Any other condition that increases the risk for complications associated with surgical procedures.

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How is DBS done?

Types of DBS

DBS involves two surgical procedures, one to implant the electrodes in the brain, and the second to implant the neurotransmitter under the skin, near the collarbone. These 2 surgeries are done some days apart. The first surgery to implant electrodes in the brain is of 2 types:

• Stereotactic DBS: Here, the patient is first put off-medication. At the OT, his/her head is stabilized using a frame. This helps the surgeons get the right coordinates to implant the electrodes. The patient is awake, is on local anaesthesia and mild sedatives.
• Interventional image-guided DBS: Here, the patient is asleep under general anaesthesia. A CT scan or MRI scan is used to relay images of the brain to a computer screen. This guides the surgeons’ movements.

Initiating a DBS therapy follows the below sequence:

Surgery 1: Implanting the Microelectrodes (or ‘lead’)

• On the day of the procedure, the patient has to remove clothing, jewellery, watch and any other accessory that could interfere with the procedure.
• The surgery team will shave some hair behind the hairline. Then local anaesthesia is injected into the scalp.
• The head-frame (or “halo”) will be attached to the skull using screws. It will remain in place during the entire procedure to prevent the head from moving.
• The team uses CT or MRI to select the target spot inside the brain where the electrodes will go.
• More numbing medication is given. Then the surgeon drills a small hole in the skull to insert the lead.
• The team monitors the process as the electrode(s) move through the brain tissue to ensure their accurate placement. The patient may be asked to move his/her arms, legs or face in between, and recordings taken.
• The external neurostimulator is attached to the lead. Electrical impulses are given for a short period of time. This helps to check if there is a positive response, or negative side-effects such as muscle contractions or visual phenomena.
• An extension wire is attached to the lead and then implanted under the scalp. This helps connect the lead to the neurostimulator, and will be required once DBS therapy begins.
• The opening in the skull is closed using a plastic cap. The wound is cleaned and stitched up.

Surgery 2: Implanting the Neurostimulator

This is done under general anaesthesia. The neurostimulator is inserted under the outer layers of skin just below the collarbone in most cases, or in the chest or abdomen sometimes. Then the extension wire from the lead is attached to the neurostimulator.

In the Hospital

After both surgeries, the patient stays in the hospital for 24 hours. In this duration, the vitals are monitored and side-effects of anaesthesia if any are noted and taken care of.

At Home

• The patient is given instructions on how to keep the incisions clean and dry and how to bathe.
• Stitches are removed during a follow-up visit.
• Adhesive strips if used should be kept dry, and will fall off on their own after a few days.
• The patient is given a magnet that helps to turn on or off the neurostimulator.

Programming the Neurostimulator

• Just before discharging the patient, the neurotransmitter is activated.
• The patient returns to the hospital a few weeks after the second surgery. Over several sessions, neurotransmitter is programmed and re-programmed to ensure optimal signal-strength. At the same time, the responses are monitored constantly.
• Oral medication for PD such as levodopa will be continued. Such medication and DBS together help achieve the desired improvement in the patient’s quality-of-life.

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Also Read: The Hindu Reports: Kauvery Hospital Achieves Major Breakthrough in Parkinson’s with Advanced DBS Surgery

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Kauvery Hospital is globally known for its multidisciplinary services at all its Centers of Excellence, and for its comprehensive, Avant-Grade technology, especially in diagnostics and remedial care in heart diseases, transplantation, vascular and neurosciences medicine. Located in the heart of Trichy (Tennur, Royal Road and Alexandria Road (Cantonment), Chennai (Alwarpet & Vadapalani), Hosur, Salem, Tirunelveli and Bengaluru, the hospital also renders adult and pediatric trauma care.

Chennai Alwarpet – 044 4000 6000 •  Chennai Vadapalani – 044 4000 6000 • Trichy – Cantonment – 0431 4077777 • Trichy – Heartcity – 0431 4003500 • Trichy – Tennur – 0431 4022555 • Hosur – 04344 272727 • Salem – 0427 2677777 • Tirunelveli – 0462 4006000 • Bengaluru – 080 6801 6801

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