Simplified: All You Need To Know About Deep Brain Stimulation.

WFY BUREAU, USA: Deep brain stimulation (DBS) is a surgical technique in neurology that employs implanted electrodes and electrical impulses to address movement disorders linked to Parkinson’s disease (PD), essential tremor, dystonia, and additional neurological ailments.

DBS may be employed in cases where conventional medications for movement disorders or neuropsychiatric conditions have yielded diminished results or their adverse effects hinder an individual’s everyday functioning.

ESSENTIAL INFORMATION TO BE AWARE OF

• During a surgical operation, surgeons insert one or more petite wires (referred to as leads or electrodes) into the brain.
• These leads receive gentle electrical stimulation from a compact pulse generator that is surgically implanted in the chest.
• For a successful DBS procedure, it is crucial to carefully select suitable patients, accurately position the electrodes, and appropriately calibrate the pulse generator.
• DBS does not completely eliminate the symptoms of PD or other ailments, but it can reduce the reliance on medications and enhance the overall quality of life for patients.

How does deep brain stimulation function?

Disrupted electrical signals in the regions of the brain that govern movement are responsible for the manifestation of movement-related symptoms in Parkinson’s disease and other neurological disorders. DBS, when successful, disrupts the irregular signals that trigger tremors and other movement-related symptoms.

Following a series of assessments to determine the ideal placement, neurosurgeons surgically implant one or more wires, referred to as “leads,” within the brain. These leads are connected to a small neurostimulator (electrical generator) implanted beneath the collarbone, similar to a cardiac pacemaker, via an insulated wire extension. Continuous pulses of electrical current originating from the neurostimulator travel through the leads and into the brain.

Several weeks after the neurostimulator has been positioned, the doctor programmes it to emit an electrical signal. This programming procedure may require multiple visits spread across weeks or months to ensure proper adjustment to the current state and achieve optimal outcomes. In the process of fine-tuning the device, the doctor aims to strike a balance between enhancing symptom management and minimising potential side effects.

Who qualifies as a candidate for deep brain stimulation?

DBS encompasses more than a mere surgical procedure. It entails a sequence of assessments, interventions, and consultations both prior to and following the actual surgery, necessitating individuals seeking DBS treatment to allocate a significant amount of time to the process.

For instance, individuals residing far from a medical centre offering DBS surgery may have to invest considerable time in commuting to and from appointments.

The expenses associated with the procedure, as well as the pre-operative evaluation and post-operative follow-up, can vary depending on the individual’s insurance coverage. While DBS surgery is an FDA-approved treatment for Parkinson’s disease, Medicare and most private insurers cover the procedure; however, the extent of coverage is contingent upon the specifics of each person’s insurance policy.

Prospective patients should maintain realistic expectations regarding the outcomes of DBS. Although DBS can ameliorate the movement symptoms associated with Parkinson’s disease and substantially enhance the quality of life in appropriately selected patients, it is improbable to restore anyone to a state of perfect health.

Parkinson’s Disease

DBS tends to benefit three categories of PD patients:

1. Individuals with uncontrollable tremors that have proven unresponsive to medications
2. Patients whose symptoms demonstrate favourable responses to medications. However, they encounter severe motor fluctuations and dyskinesias when the effects of the drugs diminish, despite adjustments in medication dosage.
3. Individuals whose movement symptoms could potentially improve with higher or more frequent doses of medication. Nevertheless, they are constrained from doing so due to the presence of undesirable side effects.

Essential Tremor

The most prevalent movement disorder is essential tremor, and DBS can serve as an efficacious treatment, particularly in severe cases where the tremors prove debilitating, hindering daily activities such as dressing, shaving, and eating or drinking. Since tremor constitutes the sole symptom of essential tremor, DBS can enhance the quality of life for individuals with this condition and enable them to function normally.

Dystonia

Dystonia, though relatively uncommon as a movement disorder, manifests as abnormal postures and twisting movements that can potentially respond to DBS when medications fail to provide satisfactory relief. The individual’s response to DBS depends on the underlying cause of dystonia, be it genetic, drug-induced, or another factor. In cases where the cause remains unknown, the doctor is likely to conduct additional tests as part of the DBS evaluation.

Psychiatric Conditions

Some recent studies have indicated the potential benefits of DBS surgery for individuals with depression, obsessive-compulsive disorder (OCD), or Tourette’s disorder. However, further research is necessary to ascertain the effectiveness of DBS in treating psychiatric disorders and to evaluate whether the benefits outweigh the associated risks and side effects.

Selecting or opting for Deep Brain Stimulation Surgery

DBS surgery is not advisable for every individual affected by Parkinson’s disease or other movement disorders. Consulting with a movement disorder specialist neurologist can help ascertain whether an individual is a suitable candidate for DBS.

Factors Influencing a Physician’s Decision on Deep Brain Stimulation

As per the National Parkinson Foundation, an ideal candidate for DBS surgery to treat Parkinson’s disease would exhibit the following criteria:

• Significant interference in daily activities caused by PD symptoms.
• Fluctuations in mobility due to PD medications, including the “on-off” phenomenon, with or without dyskinesia (involuntary jerking movements, particularly in the arms and head).
• A sustained positive response to PD medications, even if the duration of their effectiveness has decreased compared to previous experiences.
• A medical history involving various combinations of PD medications while under the care of a neurologist specialising in movement disorders.

Possible Disqualifying Factors for DBS Surgery

• Certain conditions or circumstances may deem an individual less suitable for DBS surgery:
• Predominant issues with balance, walking, or experiencing freezing as the primary disabling symptom.
• Speech difficulties are the main symptom.
• Persistent confusion, memory impairment, and cognitive challenges.
• Unresolved or unstable psychiatric conditions like depression or anxiety despite previous treatment attempts.
• Presence of other medical conditions that elevate the risks associated with surgery.

**Some of these factors could potentially be addressed through appropriate treatment. Having one or more of these factors does not automatically disqualify an individual from undergoing DBS surgery in the future. However, the doctor may advise pursuing more intensive therapies targeting these concerns before considering surgery.

Preparatory Tests for Deep Brain Stimulation

Before undergoing deep brain stimulation (DBS), patients with Parkinson’s disease undergo several evaluations to ensure optimal outcomes. The process involves the following steps:

1. Assessing Levodopa Responsiveness: The doctor confirms the patient’s responsiveness to levodopa, a medication used to manage Parkinson’s symptoms. This evaluation helps identify the symptoms most likely to benefit from DBS, which are then discussed with the patient.
2. Observation of Medication Effects: The movement disorders neurologist examines the patient both on and off PD medications. By observing the impact of these medications on motor and non-motor symptoms, the physician and patient can pinpoint the most suitable target symptoms for DBS treatment.
3. Cognitive Evaluation: A cognitive assessment is conducted to determine the patient’s cognitive abilities, as they play a crucial role in actively participating in the procedure. This evaluation helps assess the risk of potential cognitive complications following the surgery or during the adjustment phase of the neurostimulator.
4. Additional Assessments: Some medical centres also conduct occupational therapy reviews or assessments of speech, language, and swallowing functions. Furthermore, a psychiatrist may evaluate the patient to address any existing conditions, such as depression or anxiety, that may require treatment before the DBS procedure.

These comprehensive tests enable the medical team to gather essential information, tailor the treatment approach, and ensure the safety and effectiveness of DBS for each individual.

The Deep Brain Stimulation Procedure

The surgical approach for deep brain stimulation (DBS) can vary depending on the case. In some instances, both the lead and the neurostimulator are inserted during the same surgery. However, in other cases, these surgeries may be performed separately, with the neurostimulator being implanted days or weeks after the lead placement.

Distinction between Stereotactic DBS and Interventional Image-Guided DBS

Stereotactic DBS surgery requires the patient to discontinue their medication. Throughout the procedure, a frame is used to stabilise the head and provide coordinates that help guide the lead to the precise location in the brain. The patient receives local anaesthesia to ensure comfort at each step and a mild sedative to promote relaxation.

On the other hand, during image-guided DBS surgery, such as with interventional MRI (iMRI) or a CT scan, the patient is typically under general anaesthesia and in a state of sleep while the surgeon uses brain images to navigate the lead to its intended target.

Certain specialised centres offer both stereotactic and iMRI-guided options for DBS surgery. In such cases, the doctor and patient engage in a discussion to determine the most suitable procedure based on various factors.

For example, an image-guided procedure might be recommended for children, patients with severe symptoms, individuals who experience heightened anxiety or fear, or cases where the leads are targeting specific areas of the brain.

Typically, the DBS surgery follows the following steps:

• Lead Implantation
• The individual prepares for the procedure by removing any clothing, jewellery, or other items that could potentially interfere.
• A small area of hair behind the hairline is shaved, and the surgical team administers local anaesthesia to numb the scalp for the placement of the head frame.
• The head frame, also known as the “halo,” is secured to the skull using screws and remains in position throughout the entire procedure to maintain the head’s proper alignment.
• Using CT or MRI scans, the team precisely identifies the target location in the brain where the lead will be inserted.
• After applying additional numbing medication, the neurosurgeon drills a small hole in the skull to carefully introduce the lead.
• The team meticulously monitors and records the lead’s progression through the brain tissue to ensure accurate placement. At specific intervals during the recordings, the individual may be asked to perform movements with their face, arm, or leg.
• Once the lead is correctly positioned, it is connected to an external neurostimulator. By delivering electrical stimulation through the lead for a brief period, the doctors can assess whether symptoms improve or if any side effects, such as muscle contractions or visual phenomena, manifest.
• An extension wire is attached to the lead and discreetly placed under the scalp, establishing the connection between the lead and the neurostimulator.
• Finally, the opening in the skull is closed using a plastic cap and stitches.

Microelectrode Recording

Microelectrode recording (MER) employs a high-frequency electrical current (5–100 uA) to precisely determine the optimal site for implanting the deep brain stimulator (DBS). This technique, developed at Johns Hopkins and supported by the Task Force on Surgery for Parkinson’s Disease of the American Academy of Neurology Therapeutic and Technology Assessment Committee, offers remarkable accuracy.

Given the inherent variability in brain structure among individuals, MER provides crucial information for the precise placement of the DBS. By utilising a microelectrode, the surgical team can observe and analyse neuronal activity from different regions of the brain, identifying specific structures based on distinctive patterns of neuronal behaviour. To obtain high-quality information, the patient must remain awake throughout the procedure, avoiding general anaesthesia.

Placement of the Neurostimulator

This step is performed while the individual is under general anaesthesia, ensuring they are asleep. The surgical team implants the neurostimulator beneath the outer layers of skin, typically positioned just below the collarbone, although sometimes in the chest or abdomen. The extension wire from the lead is then connected to the neurostimulator.

After Deep Brain Stimulation Surgery

During the Hospital Stay

Typically, the duration of hospitalisation following DBS surgery is 24 hours, although it may be extended based on the patient’s recovery and readiness to be discharged. The doctor will make regular visits to assess the patient’s readiness to leave and provide instructions for home care.

Upon Returning Home

Once at home, it is crucial to maintain cleanliness and dryness around the incisions. The doctor will provide specific guidance on bathing while the surgical site heals. If stitches were used, they will be removed during a follow-up visit to the doctor’s office. Adhesive strips, if applied, should be kept dry and will generally come off within a few days.

The patient will receive a magnet that can be utilized, as directed by their doctor, to activate or deactivate the neurostimulator.

Programming the Neurostimulator

Once the DBS lead(s) and neurostimulator are in position, the patient will revisit the doctor for the programming of the neurostimulator to achieve optimal electrical stimulation. Programming typically commences a few weeks after the DBS procedure, although some doctors activate the neurostimulator before the patient’s discharge from the hospital following surgery.

Programming requires time and may necessitate multiple appointments to fine-tune the neurostimulator settings. Simultaneously, the doctors will address the patient’s medications and dosages to ensure effective synergy between the medications and electrical stimulation for symptom control.

Even after the adjustments, regular checkups are necessary. The frequency of follow-up appointments is determined by the doctor based on each patient’s individual circumstances.

The neurostimulator operates on a battery that typically lasts between three and five years. When the battery starts to deplete, doctors can replace the neurostimulator through an outpatient procedure. Additionally, there are rechargeable neurostimulators that have a longer battery life but necessitate regular recharging.

Long-Term Effects of Deep Brain Stimulation

DBS surgery can significantly alleviate symptoms of Parkinson’s disease such as tremors, stiffness, slowness, and dyskinesias. It can also reduce the medication dosage required to manage the condition.

Studies tracking patients after DBS have revealed that many individuals experience continued improvement in their symptoms for several years following the procedure, enabling them to perform essential activities like eating, using the bathroom, and self-feeding. However, patients undergoing DBS for movement disorders may or may not encounter changes in memory, cognition, or mood.

It is important to note that Parkinson’s disease is a progressive disorder that cannot be completely halted. While DBS effectively targets tremors, stiffness, and slowness, other symptoms such as poor posture, speech impairments, gait freezing, balance issues, and dementia may still manifest.

Post-Deep Brain Stimulation Precautions

Generally, individuals who have undergone DBS surgery should:

• Always carry an identification card stating that you have a DBS neurostimulator. Additionally, wearing a medical identification bracelet indicating this information may be beneficial.
• Inform airport security personnel about the neurostimulator before passing through airport detectors. While most airport detectors are safe for pacemakers, the small metal components in the neurostimulator may trigger the alarm. If selected for additional screening using handheld detector devices, patients should politely remind the screeners not to hold the detector wand over the neurostimulator for an extended period as the magnets within the device could potentially impact its function or programming.
• Certain MRI procedures may not be suitable for patients with leads and neurostimulators. It is essential to consult with a physician prior to any MRI, although DBS can be compatible with MRI under specific circumstances. Patients should avoid locations with strong magnetic fields, such as power generators and automobile junkyards utilising large magnets.
• Heat should be avoided during physical therapy sessions to treat muscles in patients who have undergone DBS surgery.
• High-voltage or radar machinery, including radio or television transmitters, electric arc welders, high-tension wires, radar installations, or smelting furnaces, should be avoided.
• If a surgical procedure is scheduled, patients must inform the surgeon well in advance about the presence of a neurostimulator. It is important to seek advice regarding special precautions before and during the surgery, as certain equipment, like the electrocautery device used for controlling bleeding, may interfere with the neurostimulator.
• During physical, recreational, or sports activities, patients should take measures to protect the area where the neurostimulator is placed from any potential trauma. A blow to the chest near the neurostimulator can affect its functioning and should prompt a visit to the doctor.

-WFY BUREAU, USA

****The information provided in this article is for informational purposes only and should not be considered as medical advice or a substitute for professional medical expertise. Readers are advised to consult with a qualified healthcare professional before making any healthcare decisions or taking any actions based on the information provided in this article. The author and the publisher of this article are not responsible for any errors or omissions or for any consequences resulting from the use of the information presented here. The content of this article is solely the opinion of the author and does not necessarily reflect the views of the publisher. The mention of any specific product, treatment, or procedure in this article does not constitute an endorsement or recommendation by the author or the publisher.