transcranial magnetic stimulation , deep brain stimulation and vagal nerve stimulation
- 1. Anas zaitoun 5th year medical student Jourdan university of science and technology
- 2. definition of TMS : Transcranial magnetic stimulation (TMS) is a procedure that uses magnetic fields to stimulate nerve cells in the brain to improve symptoms of depression. Transcranial magnetic stimulation may be tried when other depression treatments haven't worked. With TMS, a large electromagnetic coil is placed against your scalp near your forehead. The electromagnet used in TMS creates electric currents that stimulate nerve cells in the region of your brain involved in mood control and depression
- 4. Precautions : Tell your doctor or mental health provider if: You're pregnant or thinking of becoming pregnant. You have any metal or implanted medical devices in your body. Due to the strong magnetic field produced during TMS, some people who have the following devices cannot have TMS: Aneurysm clips or coils Stents Implanted stimulators Electrodes for monitoring brain activity Any magnetic implants Bullet fragments Any other metal device or object implanted in your body
- 5. Result : If TMS works for you, your depression symptoms may improve or go away completely. Symptom relief may take a few weeks of treatment. TMS may be less likely to work if: 1- Your mental illness causes detachment from reality ( (psychosis) 2- Your depression has lasted for several years 3-Electroconvulsive therapy (ECT) hasn't worked to improve depression symptoms It's not yet known if TMS can be used to treat depression for the long term, or whether you can have periodic maintenance treatments to prevent depression symptoms from returning.
- 6. Deep brain stimulation : Deep brain stimulation involves implanting electrodes within certain areas of your brain. These electrodes produce electrical impulses that regulate abnormal impulses. Or, the electrical impulses can affect certain cells and chemicals within the brain. The amount of stimulation in deep brain stimulation is controlled by a pacemaker-like device placed under the skin in your upper chest. A wire that travels under your skin connects this device to the electrodes in your brain. Deep brain stimulation is used to treat a number of neurological conditions, such as: Essential tremor Parkinson's disease Dystonia Deep brain stimulation is also being studied as a treatment for epilepsy, cluster headaches, Tourette syndrome, chronic pain and major depression. Many candidates for deep brain stimulation are participants in clinical trials.
- 8. Surgery risks : Deep brain stimulation involves boring small holes in the skull to implant the electrodes, and surgery to implant the device that contains the batteries under the skin in the chest. Complications of surgery may include: Bleeding in the brain (hemorrhage) Stroke Infection Breathing problems Nausea Heart problems Incision scarring With deep brain stimulation, surgery isn't a one-time procedure. The batteries that are implanted in the chest have a limited life span, and when they run out, your symptoms may quickly return. Replacing the batteries requires another surgery. It's also possible for a wire connecting the batteries to an electrode to break or for other malfunctions to occur.
- 9. Possible side effect after surgery : Seizure Infection Headache Insomnia Memory problems Temporary pain and swelling at the implantation site
- 10. Possible side effects of stimulation Numbness or tingling sensations Muscle tightness of the face or arm Speech problems Balance problems Lightheadedness Unwanted mood changes, such as mania and depression
- 11. Preparation : Before surgery, you need to have medical tests to make sure that deep brain stimulation is safe for you and is a good option in your case. You also need brain-imaging studies, such as an MRI, before the surgery, to map the areas of your brain where the electrodes will be implanted.
- 12. Result : Deep brain stimulation won't cure your disease, but it may help lessen your symptoms. If deep brain stimulation works, your symptoms will improve significantly, but they usually don't go away completely. In some cases, medications may still be needed for certain conditions. Deep brain stimulation isn't successful for everyone
- 13. Vagus nerve stimulation Vagus nerve stimulation is a procedure that stimulates the vagus nerve with electrical impulses. Vagus nerve stimulation can be used to treat epilepsy when other treatments haven't worked. Vagus nerve stimulation is also a treatment for depression, and it's being studied for conditions such as multiple sclerosis, migraine and Alzheimer's disease. There's one vagus nerve on each side of your body, running from your brainstem through your neck to your chest and abdomen. With vagus nerve stimulation, a device is surgically implanted under the skin on your chest. A wire is threaded under your skin connecting the device to the left vagus nerve. When activated, the device sends electrical signals along the vagus nerve to your brainstem, which then sends signals to certain areas in your brain
- 15. Risks : Pain where the cut (incision) is made to implant the device Infection Incision scarring Difficulty swallowing Vocal cord paralysis, which is usually temporary, but can be permanent
- 16. Side effects : Voice changes Hoarseness Throat pain Cough Headache Chest pain Breathing problems, especially during exercise Difficulty swallowing Abdominal pain or nausea Tingling or prickling of the skin
- 17. When vagus nerve stimulation may be a good option : The Food and Drug Administration (FDA) has approved vagus nerve stimulation for people who: Are 12 and older Have focal (partial) epilepsy Have seizures that aren't well controlled with medications In addition, the FDA has approved vagus nerve stimulation for the treatment of depression in adults who: Have chronic, hard-to-treat depression (treatment-resistant depression) Haven't improved after trying four or more medications or electroconvulsive therapy (ECT), or both Continue standard depression treatments along with vagus nerve stimulation
- 18. Result : Vagus nerve stimulation isn't a cure for epilepsy. Most people with epilepsy won't stop having seizures altogether. But many people will have fewer seizures, as many as 30 to 50 percent fewer. Seizure intensity may lessen as well. It can take as long as two years of vagus nerve stimulation before you notice any significant reduction in the number of seizures. Vagus nerve stimulation may also shorten the recovery time after a seizure. People who've had vagus nerve stimulation to treat epilepsy generally have an improved quality of life.
Editor's Notes
- #4: In TMS therapy, an electromagnet is applied to the left side of the forehead. This induces currents in neurons in the left prefrontal cortex--where brain imaging studies have shown a deficit in activity in depressed patients. It is thought that this can induce activity and blood flow to this area, but also causes changes in areas deeper in the brain (responsible for mood regulation) to which neurons in the cortex connect. Side effects of TMS tend to be mild, especially compared to antidepressants, and the most common complaint is a mild headache
- #8: The deep brain stimulation system targets either the subthalamic nucleus or globus pallidus interna regions of the brain involved in muscle movement.
- #15: The vagus nerve is comprised of 90% afferent, i.e., sensory nerve fibers, and plays a central role in transmitting information about the functional status of various organs to the brain1. This role also entails the monitoring of the body’s inflammatory processes: When microbial infections occur, the immune cells release pro-inflammatory signals - an accumulation of which can result in systemic inflammation. The vagus nerve thus alerts the brain when there is an excess of molecules such as cytokines. The brain, now notified of a potent infection, reflexively triggers the release of anti-inflammatory substances to avert harmful inflammation2. A serendipitous electrical stimulation of the vagus nerve helped decipher that this attenuation occurs via the efferent fibers that make up the reminder of the vagus nerve. It was thus demonstrated for the first time that the brain can regulate the levels of the Tumor necrosis factor (TNF) via the vagus nerve – a mechanism termed cholinergic anti-inflammatory pathway3. Electrically stimulating the vagus nerve using pacemaker-like devices to tackle seizures in epileptic patients has been in practice since the 1990’s, and so has been the treatment of depression with vagal nerve stimulation (VNS). These procedures have relied on the fact that the vagus nerve serves as a portal to the brain stem; thus, psychiatric diseases have been the prime target of VNS4.