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PARKINSON'S DISEASE

What is Parkinson’s disease? How is it treated?

Parkinson’s disease ("PD") is a "degenerative disease" affecting the brain. Degenerative diseases are a group of disorders which result from progressive and premature death of nerve cells in the brain. “Alzheimer ’s disease” which causes progressive memory and cognitive (intellectual) decline in the elderly, is the commonest and the most popularly known degenerative disease. PD is yet another degenerative disease and is next only to Alzheimer’s disease in commonness. It is estimated that approximately 1% of people above the age of 60 years have PD, all over the world. Even though PD is generally considered as a disease of the aging population, around 10% of patients can have their onset of symptoms below 45 years of age.

In PD, the nerve cells predominantly affected are those concerned with posture of the body and movement; patients with PD, therefore, have predominantly movement related symptoms (tremor, slowness of activities, stiffness of limbs, loss of balance and difficulty to walk etc.). However the disease process in PD is not solely confined to the areas of brain controlling movement. Other areas like those concerned with sleep, mood, autonomic functions (like control of blood pressure and urinary bladder functions), behavior and intellect could also get affected to a variable degree. Abnormal functioning of these areas of the brain can result in ‘non-motor’ manifestations like a variety of sleep disturbances, depression, anxiety, psychiatric symptoms, and incontinence of urine and memory dysfunction, in addition to the well-known movement-related (motor) symptoms in PD. PD can thus have numerous “movement- related” and “non-movement related” symptoms; all these symptoms need not be present uniformly in all patients and the manifestations of PD vary widely from patient to patient. For example, some patients have prominent tremor while certain others never experience tremor.

What causes Parkinson's disease?

It is unfortunate that the reason and mechanism of nerve cell death in PD (or any other degenerative disease) have not so far been clearly discovered by medical scientists in spite of intense extensive research going on all over the world. Though PD is not familial in majority of the cases, around 5-10% of patients with PD have affected family members, and several genetic factors contributing to the genesis of PD have been identified. Some environmental factors have also been identified as contributors to the occurrence of PD. Medical science currently believes that PD occurs due to a complex interplay of many genetic and environmental factors (many of which are yet to be identified); presence of one factor alone can only rarely cause PD. Thus, it is clear that on vast majority of occasions, it is difficult to pinpoint a precise answer to a patient who is asking the question “Why did I develop this disease?”

How is Parkinson’s disease treated?

As it is not clear as to why or how the nerve cells die, there are no treatments available to modify this process (premature demise of the nerve cells) and thereby, to cure or at the least, arrest the progression of the disease. Therefore, the treatment of all degenerative diseases (including PD) are currently confined to and aimed at controlling the symptoms and improving the patient’s functioning and quality of life. Though there is no effective treatment available to cure the disease or arrest the progression of disease, there are highly effective symptom control measures (medical and surgical) with which the patients can have a good control of symptoms and lead a near normal life for many years and pursue their occupation, adhering strictly to medications, physiotherapy and regular follow-up with treating physicians to decide on modifying the dosage of medications.

How is PD differentiated from other, similar diseases?

The diagnosis of PD is largely clinical, and is arrived at by a careful analysis of the patient’s history, clinical examination, and the response to treatment. As of now, there is no laboratory investigation or imaging study (“scan”) which confirms the diagnosis of PD with 100% accuracy, excluding all other conditions. Certain other rarer degenerative disorders (eg: Progressive Supranuclear palsy (PSP), Multiple System Atrophy (MSA) etc- together lumped as “atypical Parkinsonisms” or “Parkinson Plus” syndromes) have symptoms very similar to Parkinson’s disease initially. In some cases, a careful observation of the patient, and his / her response to treatment over a period of time (sometimes a few years) may be necessary to reach a conclusion regarding whether it is PD or “Atypical Parkinsonism”. However, as there is no specific curative or “progression-preventing” treatment available to any of these degenerative diseases, the initial, inevitable delay in making a confidant diagnosis does not do any harm to the patient. The symptomatic treatment is similar for Parkinson’s disease and the other, “atypical” Parkinsonisms. The atypical Parkinsonisms as a whole respond poorly to medical treatment and do not improve with Deep Brain Stimulation.

Medical treatment of Parkinson's disease:

The recommended treatment of patients with PD in early stages is medical (i.e., with oral medications), aimed at relieving the movement-related (“motor”) and other “non-motor” symptoms resulting from the disease. As discussed above, there is no currently available treatment to restore the cells which have died off or to prevent further damage to the brain by arresting further nerve cell death. All the currently available “symptomatic” treatment modalities aim at correcting the chemical deficiencies in the brain resulting from loss of brain cells (which are the natural source of these chemicals). The most important chemical substance which becomes deficient in the brain is called ‘dopamine’ and the most important medicine used in the treatment of PD, called ‘Levodopa’ acts by replenishing this chemical in the brain. In addition, there are several other classes of medications, like “Dopamine agonists” used to treat the symptoms of PD. These medications control tremor, relieve muscle stiffness, and improve mobility and speed of movements. With proper medical treatment and physiotherapy, patients get satisfactory control of symptoms for many years, enabling them to lead a near normal life. For the patient to have a good quality of life, the “non-motor” symptoms (like depression, anxiety, sleep disturbances, constipation, urinary symptoms, sexual dysfunction etc) which could occur in some patients, also have to be identified and treated.

Thus the currently available treatment modalities only relive the patient’s symptoms and improve the quality of life. None of them can prevent the disease from worsening over the course of time. As the disease progresses, the patient is likely to require more and more medications to control the symptoms. A condition called ‘motor fluctuation’ develops - three or four doses of medications fail to give relief to symptoms through-out the day. Each dose of Levodopa will result in a period of “On” characterized by relief of symptoms. This is followed by an “Off” period where all the symptoms recur. The patient will have to take the next dose to turn “On” again. The duration of improvement with each dose of medication gradually comes down with passage of years and the patient will require more and more number of doses to remain active throughout the day. Parallel to this, a gradual worsening of the difficulties during “off” time also occurs. Another problem faced with in this stage is ‘drug induced dyskinesia’. This is characterized by abnormal, excessive ‘dancing’ movements of the body during the period when the patient is experiencing the beneficial effects of the drug (“On” period). The severity of the dyskinesias and the resulting disability also worsen slowly with passage of years. Finally, a stage is reached where the treatment with medicines becomes difficult and impossible to tailor further, as any reduction in dose (aimed at controlling dyskinesias) leads to worsening of symptoms of PD and any increase in dose to relieve the PD symptoms result in worsening of the abnormal excessive "dyskinetic" movements. Such patients have to be considered for Deep Brain stimulation.

DEEP BRAIN STIMULATION

What is Deep Brain Stimulation (DBS)?

Deep brain stimulation is a surgical procedure done in “intermediate” stages of Parkinson’s disease (PD) when medical therapy alone fails to control the patient’s symptoms adequately. It is done in patients with “motor fluctuations” with or without “dyskinesias” (Please see the section on Parkinson’s disease) who require frequent doses of medications to control their symptoms (each dose gives benefit for only a short time) and the medication doses result in abnormal excessive movements (dyskinesias). Apart from PD, Deep brain stimulation is done in certain other movement disorders like dystonia, and tremor disorders.

In PD, DBS is done typically in patients in whom there is good improvement (which may be accompanied by dyskinesias) of symptoms with medications, but the improvement lasts only for a limited period with each dose. In very advanced stages of PD, the patients start experiencing symptoms which improve only poorly (eg: imbalance and falls, “freezing” of gait, disturbances of speech) or not at all (eg: memory and intellectual decline) with levodopa and other medications. Such patients are unlikely to have any useful overall improvement of their status with DBS.

What are the beneficial effects of doing DBS?

DBS can relieve the motor (movement- related) symptoms of the disease- like stiffness of limbs, tremor and slowness- to a significant degree. Research done all over the world including our center indicate that the overall improvement in these symptoms vary from 50-70% approximately. DBS provides a stable baseline control of symptoms (Which is around 50 % or so of the symptom control obtained in the best “on” period with oral medications. However unlike the symptom control provided by medications, which fluctuates related to the administration of each dose, the benefits provided by DBS tend to remain stable). This allows reduction in the dose of medicines considerably in most cases, thus reducing the ‘drug induced dyskinesia’ (abnormal “dance-like” movements occurring during the beneficial period (“on”) of medicines). Thus, DBS, along with the modified dose of medications, provides a more predictable and sustained relief of symptoms than that provided by medical treatment alone before surgery, by reducing the ‘fluctuations’ or ups and downs of medical treatment. Even though reduction in the dose of medications is possible in the majority, only a small percentage of patients can be totally free of medications after surgery. The aim of DBS is not to withdraw medications completely, but to improve the quality of life by reducing the “motor fluctuations” (reducing the ‘off’ time parkinsonian symptoms and duration of “off” time) and ‘on’ time dyskinesias. In a well-chosen case with properly supervised concurrent medical therapy, most patients do well and are able to carry out most of their daily activities independently. It may be possible for some patients to return to work.

Will all movement related problems improve with DBS?

The symptoms like stiffness of limbs, tremor and slowness of activities are likely to have a very good response to DBS. Certain disturbances in walking (like imbalance/ falls/ “Freezing of gait” etc) may not have a similar excellent response. The reason is that these sort of problems could also occur due to neuro-degeneration (nerve cell death) happening in areas in the “brain-stem” outside those targeted by DBS, in Parkinson’s disease. Freezing of gait and other walking disturbances, which responds initially to DBS, may re-appear later because of the gradual progression of Parkinson’s disease and involvement of these areas in the brainstem crucial to walking function. Generally, patients with Parkinson’s disease in whom the Freezing of Gait improves in “on” period with drugs, are likely to have improvement of Freezing of Gait with DBS also, at least temporarily. Disturbances of speech and swallowing function will not improve with DBS.

What is the effect of DBS on the non motor symptoms of PD?

Deep Brain Stimulation may give partial improvement to some of the non motor symptoms of PD, like sleep dysfunction and urinary bladder problems. However DBS doesn’t give relief to most of the other non-motor problems, like memory and intellectual dysfunction, depression, anxiety, hallucination, psychosis etc. Some of the intellectual functions like word output and fluency of speech could worsen slightly after DBS. Apart from this, DBS has not been found to have any functionally significant deleterious consequences on memory or intellectual functions. Many patients may perceive some loss of clarity of speech, after DBS, though this rarely results in any limitation in their ability to communicate verbally. Patients with depression, anxiety, hallucinations, psychosis etc need correction of these problems before undergoing surgery; otherwise there could be a worsening in the post-operative period sometimes resulting in serious medical / social consequences. Impulse control disorders (This denotes patient’s inability to control the urge to do certain pleasurable activities. The examples include “compulsive” gambling, hypersexuality, “compulsive” eating, “compulsive” shopping etc) could improve, remain stable or could worsen in some patients after DBS. Careful screening for intellectual, psychiatric and other ‘non-motor’ problems (many of which may not be evident on a routine office consultation) by specialized ‘neuro-psychological’ tests are required as part of the selection process of patients for DBS.

What is the effect of DBS on progression of PD?

DBS is NOT a cure for PD or a remedy to arrest the progression of the disease and maintain the same state. It is only a symptomatic measure to relieve the “movement-related” symptoms of Parkinson’s disease. As discussed in detail earlier, PD is a progressive neurodegenerative disease and there is no established therapy to arrest the progressive death of nerve cells happening in PD. This applies to DBS also- in spite of doing DBS, the disease continues to progress naturally. As a result, patients with DBS can later develop significant disability due to emergence / worsening of symptoms not amenable to DBS (like memory and intellectual dysfunction, bladder dysfunction, behavioral problems, freezing of gait, imbalance, speech and swallowing disturbances etc)

Can all patients with advanced PD undergo DBS?

Not all patients with advanced Parkinson’s disease are good candidates for DBS surgery. Patients with PD who have a significant degree of nonmotor problems (like memory and intellectual dysfunction, psychosis, depression) will not generally be selected for DBS, as these are not amenable to DBS. Very advanced stage patients (those who have severe walking disturbances/ balance problems/ falls/ freezing of gait, and disabled because of Parkinsonism even in drug “on” state) may not benefit from DBS. Those with advanced age and poor general health because of co-existence of other illnesses (eg: long history of diabetes/ high blood pressure; heart diseases; chronic lung diseases etc) may not be selected for DBS because their surgical risks and risks of an unsatisfactory outcome may outweigh expected benefits. There is a rigorous selection process whereby patients are put through a series of clinical evaluation tests before being identified as candidates for surgery.

How is the Deep Brain Stimulator system implanted?

The system is implanted by the Stereotactic Neurosurgeon with clinical and electrophysiological guidance by the Movement disorder specialist trained in the procedure. The neurosurgeon uses a ‘stereotactic head frame’ and imaging (MRI/ CT scan) to map the brain and locate the target within the brain. The scan is done after fixing the metallic frame on the head. Subsequently, the patient is shifted to the operating room.

The first stage is implantation of the DBS electrodes inside the brain. The target selected for implantation is an area in the brain called subthalamic nucleus, whose cells function abnormally in PD, resulting in the motor symptoms of the disease. The patient remains awake and alert during this stage, so that the neurosurgeon and a movement disorder specialist can test the stimulation to maximize benefits and minimize side effects. The patient’s scalp is anesthetized to minimize discomfort, a small hole (called Burr Hole) is put in the skull and wires are passed through it into the brain. The brain itself has no nerves to sense pain or discomfort; hence electrodes can be passed through the brain of the awake patient without any discomfort. The first set of wires passed are called ‘micro-electrodes’. These wires are passed to record the electrical activity from the target. The target (“Subthalamic Nucleus”, in the case of Parkinson’s disease) has a peculiar pattern of electrical activity, and recording it correctly ensures that the electrodes are placed at the correct position, mapped by the Neurosurgeon from the scans. This is very important as DBS system implantation is a ‘closed’ neurosurgical procedure (means that the surgery is not done by opening the skull and exposing the brain; instead, it is done through a small hole) and the surgeon is not directly seeing the target while operating.

The Micro-electrode recording system

Recordings obtained from the subthalamic nucleus

To double-check and ensure that positioning of the electrode is correct, test current is given and the patient is tested for improvement of Parkinsonian symptoms and signs and also for any unexpected side effects. During the testing, patients are asked to speak, to move their limbs and hands and to perform simple tasks while test stimulation is done. Patients are also asked about any side effects (like ‘double vision’, tingling sensation of one side of the body, difficulty to speak out) they might occur during test stimulation. All these require the patient to remain very alert and co-operative during the procedure.

Clinical testing during DBS surgery. The patient is remaining awake and has to be co-operative for testing. The stereotactic frame can be seen fixed to the patient’s head. The Movement Disorder specialist does the clinical testing while the functional Neurosurgeon slowly advances the electrodes in the patient’s brain

Improvement of Parkinsonian symptoms and signs without any adverse effects, on giving the test current confirms correct placement of electrodes. After achieving this, the ‘micro-electrodes’ are removed and the DBS electrode is placed at the same site. The whole procedure is repeated for the other side of the brain. The next stage is implantation of the Implantable Pulse Generator (Neurostimulator / “Battery”) under the skin over the chest wall. As this does not require the co-operation of the patient and is painful if done without good anesthesia, this part of the surgery is done under general anesthesia.

How does DBS work?

A device called the Neurostimulator which is similar to a cardiac pacemaker is implanted over the chest wall, under the skin. It is a device containing a battery and microelectronic circuitry. It generates electrical signals that are delivered to the brain via a thin wire with electrodes attached at the tip. The electrodes are implanted in the brain on both sides and the cables that connect it to the neurostimulator are tunneled under the scalp and the skin of the neck. Deep Brain Stimulation works by high frequency electrical stimulation of the target areas (the Subthalamic Nuclei) deep within the brain that control movements. These areas function abnormally in PD, resulting in the disabling “motor symptoms” (tremor/ slowness of activities/ stiffness of limbs etc) of the disease. High frequency electrical stimulation of these areas alters the function more towards normalcy and relieves the motor symptoms. As the non-motor symptoms of PD are generated by dysfunction of other areas of the brain, they may not be relieved by DBS of the subthalamic nucleus. Similarly, if the Neurostimulator is switched off for a few hours, the Subthalamic Nucleus goes back to the original abnormal state and all the symptoms will recur. Thus, DBS is not a permanent cure for PD.

What is meant by programming?

The frequency, intensity etc of the stimulation, and the “point” on the tip of the electrode through which the electrical pulses are delivered can be changed in a number of ways to give maximum benefit to the patient. This is called programming and is done by the movement disorder specialist, using a special device, called DBS Physician’s programmer. The Physician’s programmer has a programming head which can be placed over the skin above the implanted stimulator and the parameters of stimulation can then be modified as per requirement. Programming is much like tuning a radio - the stimulation parameters are adjusted until the optimal effect is obtained. Stimulation with higher intensities of current / stimulation of certain areas in the subthalamic nucleus can sometimes result in adverse effects like difficulty to speak out, and minor behavioral problems. The advantage of DBS over the other ‘lesioning’ surgeries mentioned below is that the adverse effects, if they occur, can be abolished / minimized by altering the stimulation parameters. Programming is done to ensure that the patient gets maximum control of the symptoms of PD at the cost of no or minimum adverse effects. The initial programming done (usually a few days after surgery) may not give the best results, as surgery related factors (for example, swelling of the brain areas concerned, resulting from the trauma of the surgery) may interfere with it. The patient often requires re-programming a few weeks later. Minor adjustments can be done by the patient, using the patient therapy controller unit provided.

Programming of Deep Brain Stimulator

What are the complications of surgery?

The surgical procedure is associated with complications like bleeding inside the brain and infection of the implants, in a small minority of cases. Bleeding serious enough to cause paralysis and other neurologic problems are rare and occur in only around 1.5% of patients undergoing surgery. Infections in the implants (which may necessitate explantation and discarding of the DBS system) have been reported to occur in around 2-3% of the patients undergoing DBS all over the world. Problems with the DBS hardware (the equipment and the wires), like errors in positioning, fracture of the electrodes etc could also occur in a similar minority. The second part (implantation of the stimulator) of the surgery is done under general anesthesia and carries all the risks of anesthesia as in any other surgery. Minor complications like epileptic fits during/ immediately after the procedure, transient mental changes like confused behavior, urinary incontinence etc are more common in the post-operative period and can be managed fairly easily. Minor behavioral and cognitive problems (like reduced fluency of speech, reduced initiative to do activities, changes in mood etc) can occur in some patients as a result of stimulation and can be corrected / minimized by programming, as discussed above. Some patients show a tendency for increased appetite, resulting in weight gain. Overweight can result in worsening mobility and should be controlled with appropriate dietary adjustments / exercises.

The risk of surgical complications could vary from patient to patient depending on factors like age, presence of other illnesses (eg: high blood pressure increases the risk of bleeding during surgery; cardiac problems may predispose to complications during anesthesia; diabetes may increase the risk of infections) etc

Ideally, when should a patient with Parkinson’s disease undergo DBS?

There is no simple, one-word answer to this question. As discussed above, deep brain stimulation surgery is a symptom-relieving measure offered to patients with PD. DBS has not so far been shown to have any ability to retard the progression of Parkinson’s disease or to prevent or delay the problems of very advanced stage Parkinson’s disease, like memory and intellectual dysfunction, psychiatric problems etc. Some of the symptoms of PD show very good improvement with DBS (eg: tremor/ stiffness of limbs); certain others may not improve that much (eg: freezing while walking; other sorts of disturbances in walking) ; a third group of symptoms may even worsen slightly following DBS (eg Clarity of speech, fluency). The profile and severity of the symptoms and the rate at which the disabilities progress in Parkinson’s disease vary widely from person to person. For example, some patients are severely disabled by tremor in spite of relatively preserved walking capabilities while some others never experience any tremors; slowness and walking difficulties predominate in them. Some patients have severe symptoms interfering with daily activities 6 or 7 years into the illness, while certain others remain active and independent with medications alone even after living for 12 -15 years with PD. The degree of handicap caused by the symptoms also depends on ones professional and social status. For example, the implications of the disease in a manual laborer who is the sole bread-winner of a family, and another, who is leading a retired life will be totally different, even if the severity of the symptoms is identical – the former would desire for a better control of symptoms even at the risks of a major surgery while the latter may not accept this risk. The decision regarding when to go for Deep Brain Stimulation surgery has to be individualized, taking into consideration various factors like the nature of symptoms and severity, expected improvement (which vary depending on the profile of symptoms in individual patient), expectations of the patient and family, employment status, surgical risks, family / social support (as the patient needs to be under the regular follow-up of the specialized team for life-long, after undergoing DBS) etc. The average duration of Parkinson’s disease, for a patient undergoing DBS surgery has been typically 11-13 years; however, there has been recent studies which showed that doing DBS earlier (before the disabilities become sufficient enough to warrant DBS as per conventional guidelines) in carefully selected patients may improve the overall quality of life of the patients. The expected benefits of DBS (improvement of symptoms, improved ability to perform daily activities, likelihood of resuming employment, better quality of life) in the individual patient has to be weighed against the potential risks and disadvantages(the small, but definite surgical risks elaborated above, need for a subsequent life-long specialized care, cost etc).

The simplest answer to the question is that “DBS should be considered when the needs and expected benefits in the individual patient outweigh the estimated risks and disadvantages of the surgery in him/her”. For example, a patient with no illnesses other than Parkinson’s disease (thus, the risks of surgery are relatively low) and in need of continuing employment (being the sole breadwinner of the family) may choose to do DBS ‘relatively early’, even when the disability resulting from PD is only moderate. On the contrary, the wise decision in another patient retired from employment and also having other illnesses like high blood pressure or heart disease (implying a higher surgical risk), will be to wait till the disability becomes sufficient enough to justify taking the higher risks of surgery.

Summarizing, patient with Parkinson’s disease can be considered for DBS, if the following general guidelines are met: (1) The duration of disease is sufficiently long enough – minimum of 4 years is generally recommended- so that the doctors have had a sufficiently long period of observation and follow-up to make a confident diagnosis of PD (2) The patient has an excellent (even though persisting only for a brief “on” period) response to medications like Levodopa (3) The “motor fluctuations” and “dyskinesias” are judged by the patient to be disturbing and needing better control than what is possible with optimum drugs (4) There are no major memory or other intellectual dysfunction, or depression or other psychiatric disturbances resulting from PD (5) There are no other major illnesses increasing the risks of surgery / other illnesses present are well controlled and taking the increased surgical risk due to them is justified by the severity of the motor fluctuations and dyskinesias in the judgment of the patient, family members and the team of doctors. (6) The patient and family have understood well the pros and cons of DBS and the expectations are realistic (7) The patient has adequate social support to maintain a constant access to the specialized care which he / she will require throughout the rest of his / her life.

The team of doctors will assess the patient and explain in detail the expected risks and benefits in the individual patient; the final decision should come from the patient and family.

What is the approximate length of hospital stay?

The length of hospitalization varies. Normally it takes a minimum of 14 days. One week of hospital stay is required prior to surgery for various pre-operative assessments. One more week is needed after surgery for wound healing and suture removal. During the week after surgery, preliminary programming is also done. Any complication during surgery may prolong the hospital stay.

What are the types of Neurostimulators? Is there any need to replace the Neurostimulator?

Two types of Neurostimulators are available- rechargeable and non-rechargeable. There is no difference in the improvement of symptoms obtained by the two stimulators. The non-rechargeable neurostimulator has to be replaced when its battery runs out of charge; on an average, it may take around 3-4 years for this to happen. The battery may run out of charge early and will require replacement earlier, if a higher current than usual need to be used for stimulation in the patient because of certain disease related factors. The re-chargeable stimulator has a life of 8-9 years (after which it needs to be replaced) as stated by the manufacturer; however, it needs to be charged once in 3-5 days, using an external re-charger. The re-chargeable stimulator is more expensive. The warranty period and the clauses for the implanted hardware including the stimulator and its accessories (like the patient’s therapy controller unit (“remote control”), the re-charger etc) are specified by the manufacturer. The manufacturer has to be contacted for any technical malfunctioning of the implanted DBS hardware/ accessories and the manufacturer shall handle such technical problems as per the clauses specified in the warranty document. The patients planning to undergo DBS surgery and their caregivers are advised to understand clearly the manufacturer’s policies regarding warranty, before undergoing the surgery. The manufacturer also provides a Patient Therapy Guide for the understanding of patients and caregivers, and it is also advisable to read and understand this before undergoing the procedure. Your doctors will help you if you have any difficulty in understanding any of the information provided in the brochures; feel free to contact them.

What are the other movement disorders in which DBS is used as treatment?

DBS is used for the treatment of other conditions like dystonia (Kindly click here to know more about dystonia ) and various tremor disorders, including Essential Tremor. In these conditions, the brain target used is different from the one used in PD (subthalamic nucleus).

What are the other surgical procedures used to treat PD and other movement disorders?

The other surgical procedures include stereotactic thalamotomy and pallidotomy. In these procedures, a small surgical “lesion” is produced in the brain target, to alter its function and relieve the symptoms. The patient is selected for these lesioning surgeries, when symptoms cannot be controlled by medical management alone and DBS is not possible due to technical or other (eg: financial) reasons. These procedures are much less expensive than DBS; however the results are also inferior to those of DBS. Generally, these lesioning surgeries can be done only on one side, as doing the surgery on both sides of the brain can have complications like significant degree of speech disturbance.

What all precautions should be taken by somebody with an implanted DBS system?

Regular follow-up is needed after surgery, to detect promptly and correct if possible those symptoms which are not amenable to DBS. These include depression, urinary bladder disturbances, behavioral problems, memory and intellectual dysfunction etc. The patient also may require programming or adjustment of medications for movement-related symptoms worsening over time.

Patients with DBS system implanted should consult the movement disorder specialist before going for any other major investigation or treatment. If a medical test is prescribed, the testing physician must be told about the implanted system.

Diathermy: Forms of diathermy like short wave diathermy, microwave diathermy or therapeutic ultrasound diathermy anywhere on the body may be risky for patients with an implanted neurostimulator system and should be avoided. Energy from the diathermy can be transferred through the implanted system, causing tissue damage and can result in severe injury or even death. Diathermy can also damage parts of the neurostimulator system. Injury or damage can occur during diathermy treatment irrespective of whether the neurostimulator system is turned ON or OFF.

Diagnostic ultrasound, electrolysis, radiation therapy, and electrocautery also should not be used directly over the implant site. During dental / other surgical procedures, monopolar cautery should be avoided. Bipolar cautery, if unavoidable, can be used with caution, with the lowest current settings possible. The grounding pad should not be placed near the DBS device. If bipolar cautery has to be used during the procedure, the voltage of the DBS needs to be turned down to zero, and the Pulse Generator (neurostimulator) should be turned OFF before the procedure starts. Precautions should be taken while using dental instruments like dental drill and ultrasonic probes used to clean the teeth. The Deep Brain Stimulation patient Therapy Guide available with the patient should be referred prior to use of bipolar cautery / any other electrical equipment on the patient, and the manufacturer of DBS system should be contacted if the compatibility of any electrical equipment is doubtful. Dental infections following the procedure should be avoided and antibiotic prophylaxis may be used if needed.

The patients should not be exposed to MRI using a full body radio frequency (RF) coil or a head transmit coil that extends over the chest area. The deep brain stimulator voltage should be reduced to zero and the stimulator should be switched off, before undergoing any sort of MRI scans. Kindly refer to the manufacturer’s guidelines provided in the patient therapy guide, and show it to the Radiologist and radiology technician, before planning any MRI study. Diagnostic x-rays do not usually cause problems, but some, such as mammograms, that require tight enclosure of the area where the neurostimulator is implanted, may require additional adjustment of the x-ray equipment.

The electrical discharge from defibrillators may damage the neurostimulator and also cause tissue damage.

The patient is provided with an identification card when they leave the hospital after surgery. This card provides basic information about the pulse generator and contact details of the treating doctor. This has to be carried while travelling. Certificate mentioning the precautions will also be given. The identification card and the certificate can be shown to security personal and is likely to help the patient bypass theft detectors, security gates, metal detectors etc (for example, in airports) which may cause parameter changes in the neurostimulator system.

In the unfortunate event of the death of a patient with DBS, the neurostimulator must be removed prior to cremation, as the device may explode if put in fire. This can be done in a near by hospital by a general surgeon.

How much experience does SCTIMST have in functional surgeries for movement disorders?

SCTIMST is the pioneer of Deep Brain Stimulation (DBS) surgery for Parkinson’s disease in India, with the first procedure of Globus Pallidus deep brain stimulation performed in India in August 1998. It is now one of the leading centres in this field in the country, with more than 350 functional neurosurgical procedures, including more than 175 DBS for advanced PD and other Movement Disorders done till December 2015. Our surgical results, indicating sustained benefit of stimulation on the cardinal signs of the disease and the quality of life of the patients followed-up regularly for up to 10 years, have been published in international journals.

DYSTONIA

What is meant by dystonia?

Dystonia is a movement disorder characterized by involuntary muscle contractions, which force certain parts of the body into abnormal, sometimes painful, twisted postures, occasionally accompanied by jerky movements. Dystonia can affect any part of the body including the arms and legs, trunk, neck, eyelids, face, or vocal cords. There are different names given to describe various forms of dystonia, usually based on the affected body part (eg: blepharospasm, oromandibular dystonia), cause of Dystonia (Eg: primary dystonia, secondary dystonia) or number of areas involved (eg: focal dystonia, segmental dystonia and generalized dystonia)

What causes dystonia?

The mechanisms underlying dystonia are not fully known. Dystonia could occur due to abnormal functioning of the basal ganglia, (which are structures located deep in the brain and involved in the control of movement), cortex of the brain, or both. Abnormalities in the interaction between basal ganglia structures and cortex also may play a role.

Is dystonia a genetic disorder?

Some forms of dystonia are due to genetic causes. Some patients with dystonia due to genetic causes are said to have ‘primary dystonia’; in such patients, dystonia will generally be the only manifestation of Nervous system dysfunction. The patient’s intellect and other aspects of nervous system function will usually be normal. Primary dystonia staring in childhood or early adult hood tends to spread to multiple parts of the body or even the whole body with passage of time while those starting during mid or late adult hood tend to remain confined to one or a few of the body parts. “Secondary dystonia” result from specific causes like exposure to certain medications and toxins, traumatic injury to brain, certain hereditary and “degenerative” conditions affecting the brain, infections or stroke. Sometimes dystonia can occur due to degenerative diseases causing widespread nervous system dysfunction; in such cases, manifestations other than dystonia (like intellectual dysfunction, imbalance, epileptic fits etc) also occur very often.

Focal Dystonia is one which affects only one part of the body. The common forms include: Blepharospasm: Affects the muscles of the eyelids, forcing them to close. The spasm may become sufficiently severe to render the patient unable to see, although the eyes and vision are normal. Cervical dystonia: Affects muscles in the neck and shoulders. The muscle spasms can be painful and cause the neck to twist to one side (Torticollis), forward (antecollis), or backward (retrocollis). Oromandibular dystonia: The muscles of the lower face undergo spasm. The jaw muscles that pull the mouth open or close may be involved. Writer’s Cramp: This is a ‘task-specific’ dystonia in which the hand and forearm muscles contract during the act of writing. The patient usually has no symptoms while doing other activities (like buttoning his shirt or eating) with the affected hand. Similar ‘task-specific’ dystonia may arise in musicians when a violin is played or certain fingers are moved while playing a flute or other musical instrument.

Hemifacial Spasm: This is very similar to dystonia and is treated similarly with botulinum toxin injections. However, in hemifacial spasm the signals for the abnormal movements are generated not inside the brain, but more peripherally, in the nerve supplying the muscles of face (Facial Nerve). As a result of this, the muscles on one side of the face contract irregularly. Rarely, this is secondary to inflammation or irritation of the facial nerve.

The Diagnosis of Dystonia:

The diagnosis of dystonia is clinical, and a Neurologist trained in movement disorders can make it by carefully observing the abnormal movements which the patient is having. Certain electrophysiological tests can assist the diagnosis in difficult cases by demonstrating simultaneous activity in various muscle groups, during the movements. Other investigations like MRI scan, blood tests and genetic studies may be required to find out the underlying cause and to differentiate between primary and secondary dystonia.

Treatment of Dystonia: The treatment can be with oral medications, botulinum toxin injection and functional neurosurgery. The aim of treatment is to relieve the muscle spasm and abnormal movements and postures so that the patient can function normally.

Botulinum Toxin:

Botulinum Toxin Injections are used for the treatment of a wide variety of indications in movement disorders. The common conditions for which botulinum toxin is used include various types of focal and segmental dystonia including torticollis, writer’s cramp, blepharospasm, oromandibular dystonia etc as well as other conditions like hemi-facial spasm and post-stroke spasticity (stiffness of muscles occurring in a limb, paralysed by stroke). Free hand injections are used for some conditions like blepharospasm and hemifacial spasm, while others like writer’s cramp and cervical dystonia may require EMG (electromyogram) guidance. The involved muscles are identified and injected using special equipments including EMG. A single session gives relief of symptoms (generally varying from 50% to 100%, depending on the condition and the muscles involved) for around 3-4 months, on an average. Subsequently, the symptoms gradually recur and the patient may require re-injection. Botulinum toxin acts by blocking the abnormal signals from nerves, from reaching the muscles injected. Botulinum toxin injections are generally safe. The most common side effect (apart from the pain resulting from injection) is a transient weakness of the muscle injected; the weakness will completely disappear spontaneously over a few days to weeks.

Surgical treatment is done for patients with refractory and troublesome segmental / generalized dystonia who are significantly disabled in spite of optimal medical therapy. The surgical treatment is usually offered for patients with primary dystonia only. The preferred surgical treatment is Deep Brain Stimulation (DBS), discussed in detail under the heading ‘Parkinson’s disease (PD)’. The target in the brain selected for DBS in patients with dystonia is different from the target selected in PD. Other treatment options include ablative surgeries (a small ‘lesion’ is produced in a strategic location of the target) like pallidotomy.

Post Doctoral Fellowship Program in Movement Disorders

The Comprehensive Care Center for Movement Disorders, Sree Chitra Tirunal Institute for Medical Sciences and Technology, Kerala, currently offers 1 year Post Doctoral Fellowship Program in Movement Disorders. The programs begin on the 1st of January. Applications are invited in August-September and notified through national dailies and institute’s website. The program is organized under the supervision of experienced faculty trained in Movement Disorders in internationally reputed centers.

Prerequisite for applicants:

Postdoctoral fellowship positions are open to candidates who are interested in movement disorders and have 1) a doctoral degree of DM (Neurology) or its equivalent and 2) registration with the central/ state medical council.

Training includes:

1. Participation in the Movement Disorders Clinic catering to patients with the full range of movement disorders
2. Training in the diagnosis and treatment of various movement disorders
3. Academic programs including video sessions of unusual and interesting disorders and their diagnosis and management, seminars, bed-side case discussions and journal clubs
4. Active participation in the botulinum toxin clinic.
5. Exposure to the pre-operative assessment, intra-operative monitoring, post-operative care, follow-up and programming of patients undergoing surgical procedures like Deep Brain Stimulation for Parkinson’s disease and other movement disorders.
6. Clinical and basic science research opportunities eg. Molecular Genetics, Motor Physiology using Transcranial Magnetic Stimulation, Tremor analysis
7. Opportunity to present research papers in national/international conferences and participate in publication of research articles in international journals.

For more details contact:
Prof. Asha Kishore
E-mail: