The U.S. Food and Drug Administration has approved a treatment that uses focused ultrasound on both sides of the brain (in two procedures, months apart) for the management of Parkinson’s-related movement, or motor, symptoms.
The approval is an advance in focused ultrasound (FUS) treatment, a noninvasive surgical approach that uses sound waves to create heat and destroy a small area of brain tissue involved in Parkinson’s. But until this latest advance, FUS could only be performed on one side of the brain and therefore only improved symptoms on one side of the body. The new approach targets a different area of the brain, making it available to treat both sides of the brain, and therefore to treat tremor, slowness, stiffness and involuntary movement (dyskinesia) on both sides of the body.
Like all currently available treatments, focused ultrasound doesn’t cure Parkinson’s or slow or stop its progression. But it may ease motor symptoms for people who experience ongoing challenges despite medication and other treatments. The Michael J. Fox Foundation was an early funder of focused ultrasound research and has continued to support efforts to advance this technology.
“The FDA approval of bilateral focused ultrasound represents another treatment option for people with progressing Parkinson’s,” said Rachel Dolhun, MD, DipABLM, principal medical advisor at The Michael J. Fox Foundation. “It’s heartening to see the continued expansion of options for progressing disease, many of which gained FDA approval in recent years — medication infusions, adaptive deep brain stimulation, and now bilateral focused ultrasound. More options mean more chances to better control symptoms and improve life with Parkinson’s.”
How Does Bilateral FUS Work?
FUS is an incisionless surgical procedure that targets a small area of brain tissue involved in Parkinson’s symptoms. During the procedure, ultrasound waves, guided by a surgeon and magnetic resonance imaging (MRI), damage a small area of nerve fibers to lessen motor symptoms. The benefits are typically immediate, and the procedure is irreversible.
One-sided, or “unilateral,” FUS was first FDA approved in 2018 to treat Parkinson’s-related tremor, and in 2021 for additional motor symptoms and complications, like dyskinesia and ups and downs in symptom control (motor fluctuations). Because it was one-sided, it only eased symptoms on the opposite side of the body. The newly approved bilateral approach from the biomedical device company Insightec targets each side of the brain in separate procedures, spaced at least six months apart.
It also targets a different area of the brain: connections between nerve cells (the pallidothalamic tract) rather than the nerve cells themselves (the globus pallidus interna or the ventral intermediate nucleus of the thalamus). It’s like cutting the wiring rather than turning out all the lights. By disrupting faulty communication pathways, the treatment aims to ease motor symptoms.
Is Bilateral FUS Right for Everyone?
FUS is sometimes considered for people who continue to have movement symptoms despite medication and who cannot or do not want to have deep brain stimulation (DBS). Not everyone is a candidate for focused ultrasound. Eligibility depends on many factors, including symptom severity, brain anatomy, response to levodopa, skull density and overall health.
Many people wonder about the similarities and differences between FUS and DBS. DBS is another surgical treatment that aims to ease motor symptoms as well as dyskinesia and fluctuations. It involves placing thin metal wires in the brain. These wires transmit small electrical pulses that lessen symptoms. DBS involves regular follow-up, adjustment and maintenance. FUS is incisionless; DBS requires implanted hardware that includes wires and a battery and needs regular programming. DBS is reversible – it can be removed or turned off; FUS is irreversible.
What Happens Next?
FDA approval means that this treatment is now considered safe and effective based on clinical trial evidence.
Those trial results are not yet public, though they have been reviewed by the FDA and are the basis for approval. Until publication of results, which is pending, it is not possible to relay the full potential benefits and side effects of bilateral focused ultrasound.
However, details of the trial itself are available. The trial included 54 people with progressing Parkinson’s who got a benefit from levodopa but had inadequately controlled motor symptoms or complications. All had one-sided (unilateral) ultrasound treatment and 40 of them went on to have the second (bilateral) treatment at least six months later. Participants were followed for at least 12 months. The study was conducted at multiple sites in the US, Spain and Taiwan in an open-label fashion, meaning both doctors and patients knew the treatment was being administered. No one received a placebo. The trial evaluated motor symptom scores, off medication, before and after treatment using the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS).
It also may take time before the treatment becomes widely accessible. Although the procedure uses the same equipment already in place at many treatment centers, and may be more immediately available for some, insurance coverage may take up to two years as decisionmakers review the new approval and update policies accordingly.
If you’re interested in this treatment, speak with your neurologist or movement disorder specialist. They can help determine whether you’re a candidate and guide you on when and where it may become available.