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With focused ultrasound (FUS), doctors guide ultrasound beams toward tiny areas of cells that cause Parkinson’s motor symptoms. Each beam is harmless on its own, but when focused together, they can create enough heat to damage small parts of the brain that contribute to symptoms. Doctors target different brain areas for different symptoms.

In 2018, the U.S. Food and Drug Administration approved focused ultrasound as a treatment for Parkinson's-related tremor. In 2021, FDA expanded approval to include other Parkinson’s symptoms, such as stiffness or slowness, as well as dyskinesia (uncontrolled, involuntary movement).  In each case, FUS was approved to treat only one side of the brain (unilateral) and therefore to treat symptoms on only one side of the body.  

In 2025, the FDA approved a new focused ultrasound technique that can be used on both sides of the brain (bilateral) through two procedures, months apart. This bilateral process treats motor symptoms and dyskinesia on both sides of the body. Learn more about who can benefit from bilateral focused ultrasound. 

Focused Ultrasound Surgery

During the FUS procedure, no general anesthesia, surgical incisions or implanted hardware is involved. While the patient is sedated yet awake, doctors use MRI brain scans to direct ultrasound beams to the target brain location. The target varies based on what symptoms are being treated and whether the procedure is one- or both-sided. One-sided focused ultrasound targeted the thalamus for tremor or the globus pallidus interna for other symptoms and dyskinesia. Both targets are clumps of brain cells, called neurons, that cause symptoms. 

Both-sided focused ultrasound works in a different area – the pallidothalamic tract – which is a group of connections between brain cells. This is like “cutting the wiring” versus “turning out all the lightbulbs” in the one-sided procedure. The procedure is carried out one side at a time, with at least six months between treatments.

Focused ultrasound typically decreases symptoms immediately. It does not require adjustment, programming or additional procedures. But it is irreversible and permanent. Possible side effects may include speech changes, headache, numbness and tingling, imbalance or gait changes, and others. 

Difference Between Focused Ultrasound and Deep Brain Stimulation 

Focused ultrasound and deep brain stimulation (DBS) are both surgical procedures that aim to ease Parkinson’s movement symptoms or dyskinesia. These therapies may be options for people who get a good response to levodopa but have complications, such as dyskinesia or “off” time. Or, they may be a consideration for people who have tremor that cannot be controlled with medication.

Unilateral focused ultrasound and DBS work in the same brain areas but in different ways. FUS destroys cells and DBS delivers small electrical pulses to those same cells to interrupt abnormal signaling. Bilateral focused ultrasound targets a slightly different part of the brain, damaging the “wiring” that carries the signals, rather than the part of the brain that produces those signals.  

All kinds of FUS are permanent and irreversible, while DBS may be reversed by removing the system or turning it off. Focused ultrasound has no incisions and there is no hardware placed in the body. In DBS surgery, doctors insert thin wires into the brain and a battery below the collarbone. For both FUS and DBS, a patient typically is awake, but some centers now offer asleep DBS. FUS is a one-time procedure (or two-time if bilateral) that does not require adjustment. DBS needs regular programming to find the right electrical stimulation settings to maximize benefit and limit side effects.

Focused ultrasound may be an option for people who can't or don't want to pursue deep brain stimulation. Some are unable to undergo invasive surgery because of other medical problems. Others may not want to manage the logistics of DBS programming and future battery replacements. Focused ultrasound may expand the available treatment choices for patients and doctors. 

Research into Focused Ultrasound

The Michael J. Fox Foundation funded an early study of focused ultrasound for dyskinesia

Ongoing research on focused ultrasound for Parkinson’s is evaluating the procedure in different brain areas affected by Parkinson’s, such as the subthalamic nucleus. 

Researchers also are studying how ultrasound could help other Parkinson’s treatments, such as antibodies against alpha-synuclein or gene therapies, get into the brain more easily and efficiently by temporarily opening the brain’s protective barrier. FUS is even being studied as a tool to collect biomarker measurements, that could be used for screening in clinical trials and potentially even diagnosis. 

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