Definition & Overview

Deep brain stimulation (DBS) is used to treat neurological disorders, which occur when the brain and the muscles are unable to communicate properly. This causes the patient to make involuntary and repetitive movements.

DBS is also used to treat chronic pain. It targets areas of the brain to block pain signals. Currently, it is tested for the treatment of other conditions. These include addiction, dementia, and depression.

The treatment requires surgery to implant a device in the brain. The device blocks abnormal signals to control or lessen the severity of symptoms. As a result, patients are able to enjoy a better quality of life. The device works the same way as a pacemaker, which fires electrical impulses to restore normal heart rhythm.

Who Should Undergo & Expected Results

DBS is widely used for the treatment of disorders and medical conditions mentioned above. But it is not the first treatment option because it is risky and very expensive.

Patients are often prescribed with medications first. DBS becomes an option if:

  • Medications start to cause serious side effects.

  • The patient’s condition has progressed.

  • The symptoms are debilitating.

  • The patient stops responding to medications.

  • The patient’s quality of life starts to decline.

  • The patient has developed medication-induced dyskinesia.

DBS is not for everyone. For patients with Parkinson’s disease, for example, the surgery is not an option if there is a history or physical symptoms of “Parkinson’s plus” syndromes. This means that symptoms progress rapidly. Patients with this syndrome also show signs of cerebellar dysfunction.

DBS is also not an option if the patient:

  • Is mentally unstable. It is the same case if their cognitive dysfunction renders them unable to tolerate awake surgery.

  • Has other serious medical conditions. These include hypertension and cardiac disease.

  • Does not have realistic expectations of the outcomes of surgery.

  • Is over 70 years old. Due to the risks of DBS, it is rarely advised for patients aged 70 and older.

  • In unable to stay calm during surgery. DBS surgery can last up to three hours. It is important for patients that they are able to cooperate throughout the procedure.

  • Cannot commit to monthly follow-ups. The programming of the DBS device is a trial-and-error process. It is important that patients are willing and able to see their doctors at least once a month for about a year after the surgery.

How Does the Procedure Work?

The following steps are taken during the procedure:

  • The patient’s head is held in place with a metal structure to prevent it from making any unnecessary movements.

  • Imaging tests are performed. These include an MRI and a CT scan. These are used to map out the brain to determine where the electrodes will be implanted.

  • Local anaesthesia is used to numb the part of the skull where a small hole will be made.

  • Electrodes are then implanted in the region of the brain involved with the disease symptoms. The patient must be awake during this procedure. The electrodes will be turned on and off. During which the patient is observed for symptoms.

  • The pulse generator is then implanted in the patient’s chest, just below the collarbone. The procedure is often done the next day after the electrodes have been implanted. The pulse generator is a small device that generates and sends electrical signals to the electrodes. This procedure is done under general anaesthesia.

  • The DBS extension is also implanted. This is an insulated cable that carries the electric signals from the pulse generator to the electrodes. A small opening is made behind the ear. The extension passes under the skin and connects to the pulse generator.

The patient is then given a couple of days to recover from surgery before the pulse generator is switched on. The different aspects of electrical stimulation pattern are then adjusted. These include the pulse frequency, shape, and strength.

Possible Complications and Risks

There is a risk of excessive bleeding if brain tissue and nerves are damaged. Other risks include infection, stroke, and heart problems as well as breathing problems and seizures. Electrical stimulation also carries certain risks. The most common are unwanted mood changes and depression as well as speech problems, numbness, and muscle tightness.

References:

  • Timmermann L, et al. Multiple-source current steering in subthalamic nucleus deep brain stimulation for Parkinson’s disease (the VANTAGE study): A non-randomised, prospective, multicentre, open-label study. The Lancet Neurology. 2015;14:693.

  • Deep brain stimulation for Parkinson’s disease. National Institute of Neurological Disorders and Stroke. http://www.ninds.nih.gov/disorders/deep_brain_stimulation/deep_brain_stimulation.htm.

  • Isaac Perry Clements “How Deep Brain Stimulation Works” 18 May 2008. HowStuffWorks.com. https://science.howstuffworks.com/life/inside-the-mind/human-brain/deep-brain-stimulation.htm 24 October 2017

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