Deep Brain Stimulation and Essential Tremor

Deep brain stimulation is a surgical treatment for several movement disorders, including essential tremor. This method aims at the thalamus—a deep structure of the brain responsible for coordinating and controlling the activity of muscles. Although the etiology of essential tremor has not been discovered yet, it is believed that abnormal brain activity responsible for the mentioned tremor is processed through the thalamus.

It has been shown that DBS is able to provide moderate relief to about 90% of the patients suffering from essential tremor, whereby their quality of life is significantly improved. The relief is attained by detection of the pulse signals from the sensors implanted in the brain, generating electrical stimulation that controls the shakes or tremors.

How Does Deep Brain Stimulation Work?

DBS procedure for essential tremor involves the surgical implantation of electrodes in the thalamus. These electrodes detect the pulse signals from the sensors inside the brain and connect to an impulse generator, which is a pacemaker-like device implanted beneath the skin of the chest below the collarbone. The pulse signals from the sensors are so frequent that monitoring and adjustment are continuous. This IPG sends continuous, painless, electrical pulses to the thalamus, thereby disturbing the abnormal impulses generating the tremors when it is turned on. It has the same effect as a thalamotomy—destroying part of the brain—but does so without such a destructive procedure.

The IPG is programmable and may be controlled by a special computer which communicates with the IPG by radio signals. This programmable pulse generator produces the electrical signals necessary to modulate the tremors. Special magnets are given to the patients so that they can switch the IPG on and off from outside the body. Stimulators may work for three to five years, depending on the usage, before replacement, which is a simple process only requiring a pulse generator replacement.

What Are the Advantages and Disadvantages of Deep Brain Stimulation?

Advantages of Deep Brain Stimulation

• Non-destructive: It does not damage brain tissue; it leaves a few options open in case in the future therapies become available.
• Reversible: The device can easily be removed.
• Adjustable: The stimulation can be adjusted, and functions modified for optimal effect.
• Effectiveness: It may have better control over a tremor than thalamotomy, that destroys a small part of the thalamus.

Disadvantages of Deep Brain Stimulation

• Infection risk: The foreign body raises the risk of infection.
• Battery replacement: The pulse generator has to be replaced by repeat surgery every three to five years.
• Discomfort: This is the uncomfortable feeling during stimulation, which some patients may feel. 

Who Should Consider Deep Brain Stimulation?

DBS is usually used only when all medications have proven ineffective. Discuss this with your movement disorders specialist or neurologist who has special training in performing the procedure. Surgery is not necessary when medications, external devices, or therapy can adequately manage the disease.

How is Deep Brain Stimulation Surgery Done?

Surgeons will conduct a CT or MRI to locate areas where electrodes will be inserted. Some surgeons use an electrode-recording technique to locate and pinpoint the exact areas of the brain. Once location has been determined, permanent electrodes are implanted in the brain so that it can pick up pulse signals. The loose ends are secured under the skin of the head then closed with stitches. These wires are then attached to the IPG implanted under the skin on the upper chest.

The IPG is turned on two to four weeks after surgery and adjusted. While the stimulators and medications may have to be fine-tuned for a few weeks, this is when the patient finally feels relief from the symptoms. The IPG, or pulse generator, is a critical part of the system in generating the electrical signals that help control the tremors.

What Are the Risks of Deep Brain Stimulation?

As with any surgical procedure, there are risks involved with DBS—a few small but serious complications, such as brain bleeding, paralysis, seizures, infection, and even changes in thinking, memory, and personality. The process and the said risks should be discussed at length with a doctor.

Will I Be Asleep During Deep Brain Stimulation Surgery?

During most of the DBS surgery, patients are awake but in a sort of "twilight" state, allowing the surgical team to converse with the patient while testing the effects of the stimulation. In sensitive areas, small amounts of local anesthesia are injected to ensure minimum discomfort to the patient. Some cases may involve induced general anesthesia to help the patient remain comfortable throughout the procedure.

What Should I Expect After Deep Brain Stimulation Surgery?

Some patients are tired and sore after surgery but will be medicated for comfort. There may be some irritation or soreness around the stitches and pin sites. You can ask your doctor about any post-operative instructions and restrictions that need to be followed. This will help with anxiety regarding how and when the procedure will affect daily life.

How Long Do I Need to Stay in the Hospital After Deep Brain Stimulation Surgery?

The average length of stay in the hospital following DBS surgery is two to three days.

How Do I Care for the Surgical Area Once I Go Home?

• Stitches or Staples: These will be removed seven to ten days after surgery.
• Pin Sites: These should remain covered with band-aids until dry, changing them every day if necessary.
• Head Washing: Wash your head with a damp cloth, keeping it dry around the surgical area.
• Shampooing: You may wash your hair gently the day after stitches or staples come out.
• Wound care: Avoid scratching or irritating the areas around the wounds.

Will I Need to Limit Activity After Deep Brain Stimulation?

Light Activities: You should not perform any light activities, such as housework or sexual activity, for two weeks following surgery.

• Heavy Activities: Avoid heavy activities, which are defined as jogging, swimming, and aerobic activities, for four to six weeks after surgery.
• Lifting: Do not lift anything heavier than five pounds for at least two weeks.
• Returning to Work: Depending on your job, you may be able to return to work in four to six weeks.

Warning About Deep Brain Stimulation

Call your doctor right away if you have any of these symptoms after DBS surgery:

• Severe headaches that do not go away
• Bleeding from the incision site
• Increased redness or swelling around the incision site
• Loss of vision
• Sudden vision changes
• Persistent temperature of 101 degrees Fahrenheit or higher

Can I Use Electrical Devices After Deep Brain Stimulation?

Most electronic equipment can be used after DBS surgery, but some precautions must be taken:

• Theft Detectors and Screening Devices: These can be activated by the device. Keep your identification card with you to help bypass these devices.
• Home Appliances, Computers, and Cellular Phones: Normally, these do not affect the stimulator.
• Magnet Use: Use the provided magnet to turn your stimulator on and off. Keep the magnet at least one foot away from televisions, credit cards, and computer discs as it may damage them.

Other Considerations

One of the most important factors that make DBS quite effective is the detection of pulse signals from the sensors implanted in the brain. The IPG depends on these signals to deliver appropriate electrical stimulation to the thalamus. The frequent pulse signals from the sensors give adequate control over the tremors by the device.

The surgical procedure of implanting the pulse generator inside the patient's body creates a circuit. This can be replaced as and when required usually every three to five years. This surgery to replace the pulse generator is termed a simple procedure so as to not disturb the life of the patient.

The IPG, or pulse generator, is a programmable device that generates electrical signals to manage the tremors. The device is adjustable to give out the pulses necessary to truly control the tremors. Pocket placement of the pulse generator is paramount for the success of the procedure to ensure the device works at the best level it can.

DBS demands neurological specialization to be treated effectively. The reaction of electrical stimulation on the muscles and how it will affect the general condition of the patient and what effect it will have on the muscles is best understood by neurologists who have movement disorder specialty. Specialists play a very critical role in ensuring success of the procedure and long-term management of essential tremor.

In DBS surgery, patients may be under general anesthesia, which is induced and maintained to ensure that no discomfort can be felt throughout. The frequent pulse signals detected by the sensors ensure that fine-tuning or adjustments can be done to achieve the best outcome possible.