Nearly 1 million people in the US live with Parkinson’s disease. That number is expected to rise to around 1.2 million by 2030. There is no cure for this medical condition, and Parkinson’s disease patients are treated based on the individual symptoms that they present.
A primary symptom of Parkinson’s disease is tremor. According to the Parkinson’s Foundation, about 70% of people with Parkinson’s disease experience tremors at some point during the disease. Typically, this will be a rest tremor, which happens when a person is not moving, mainly affecting their hands. However, tremors are also common in the lower lip, jaw, and leg.
Treatment of Tremors
- Dopaminergic Medications: Parkinson’s disease is a neurodegenerative disorder that affects dopamine-producing neurons in a specific area of the brain. This may mean that either no or only low levels of dopamine are produced. Therefore, most symptoms of Parkinson’s disease, including tremors, will be primarily treated with a dopaminergic medication designed to increase the dopamine levels in the patient’s brain or activate dopamine receptors.
- Anticholinergic Drugs: If dopaminergic medications are not helping reduce tremors, doctors may decide to try anticholinergic drugs. These drugs aim to decrease how much acetylcholine, a neurotransmitter that affects movement, is active in the brain. Reducing the amount of acetylcholine will hopefully bring it more in balance with reduced dopamine levels.
Surgical Treatments of Tremors
Deep Brain Stimulation: When medications are not effectively treating tremors, Deep Brain Stimulation (DBS). DBS is a surgical procedure that has been successfully used to treat a medicinally resistant tremor. It was first approved in 1997 for treating Parkinson’s disease tremors. Five years later, it was also approved as a treatment for advanced Parkinson’s disease symptoms, and in 2016, it was approved for early-stage Parkinson’s disease.
DBS surgery involves a surgeon inserting electrodes into a targeted area of the brain, using MRI (magnetic resonance imaging) and recordings of brain cell activity to guide them. Once the electrodes are in place, a second procedure is performed to implant an impulse generator (IPG) battery under the collarbone or in the abdomen. The IPG acts similarly to a pacemaker, providing an electrical impulse to the part of the brain involved in motor function. While it does not offer a cure for Parkinson’s disease, DBS relieves symptoms. The downside of the treatment is that it is invasive and carries rare but serious risks associated with surgery.
MR-guided Focused Ultrasound Treatment: In recent years, a new non-invasive therapy called Magnetic Resonance-guided focused ultrasound treatment (MRgFUS) has been developed to treat essential tremor, the most common form of tremor. In 2016, the US Food and Drug Administration (FDA) made it an FDA-approved treatment for patients with essential tremors.
Tremors are caused by abnormal activity in the brain’s thalamus, which is the area of the brain that sends out motor and sensory signals. MRgFUS uses focused ultrasound energy to cauterize the affected brain tissue, creating a break in the abnormal activity.
The procedure involves placing an ultrasound device on the head, which will emit high-intensity ultrasound waves. As with DBS, the surgeon will use an MRI machine to relay images to help guide them to the targeted area. Once in place, they will then use over a thousand beams of ultrasound to slowly raise the targeted tissue’s temperature. As the temperature rises, the surgeon will monitor the effects to ensure that the treatment is working. The aim is to eventually cause a burn that destroys the affected tissue without affecting any non-targeted areas.
The obvious benefits of this method, aside from it being an outpatient procedure, are that no incisions are made, and no holes need to be bored into the skull. Patients also do not require an implanted device. Because there is no need for general anesthesia, there are fewer potential side effects. Additionally, the treating physician can see the procedure results in real-time and stop the treatment if they see any adverse effects.
Using MRgFUS will depend on the patient and their symptoms. The procedure can last up to four hours, and while the medical staff will give medications to help, many patients may find it hard to lie in one position for that time. It is also most effective for essential tremor patients, which will benefit patients with tremor-dominant Parkinson’s disease. Parkinson’s disease patients with milder tremor symptoms may not benefit to the same degree.