A new approach to focused ultrasound (FUS) for Parkinson’s is in the news.
FUS is a non-invasive procedure that carefully concentrates ultrasound waves to destroy brain cells involved in Parkinson’s. Currently, FUS is approved by the U.S. Food and Drug Administration to treat Parkinson’s tremor that does not respond to medication. It also is approved for essential tremor, another movement disorder that causes shaking of the hands, head or voice. In these cases, FUS targets a part of the brain called the thalamus.
Researchers now are testing focused ultrasound in different brain areas for potential benefits on other Parkinson’s motor symptoms, including stiffness and slowness. One trialthe New England Journal of Medicine, recently reported results: FUS on a small brain territory called the subthalamic nucleus (STN) decreased motor symptoms, but also caused potential side effects.
In the randomized, controlled trial, researchers performed FUS on one side of the brain in people with asymmetric Parkinson’s (more significant symptoms on one side of the body), which could not be controlled with medication. Of 40 participants, 27 had focused ultrasound of the STN. For comparison, the others had a “sham” procedure, which mimics the motions of FUS but does not deliver treatment. Those who underwent FUS had reduced scores on the MDS-UPDRS Part III (a scale that measures motor symptoms), but increased side effects, such as weakness, dyskinesia, speech changes or walking problems. For some, side effects were temporary (lasting a few months or less); for others, they persisted longer.
These results help point to additional needs — learning more about potential benefits and risks of FUS for different aspects of Parkinson’s, the optimal brain target, and the best candidate for the procedure. As understanding evolves, focused ultrasound may become more broadly available to more people with Parkinson’s. (It also may be a way to help deliver therapies more effectively — other ongoing trials are testing FUS not to destroy cells, but to assist Parkinson’s treatments with getting into the brain.) For now, FUS remains FDA-approved for only Parkinson’s tremor, and research to treat other symptoms continues.