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Are there any side effects associated with MR-guided focused ultrasound treatment?

MR-guided focused ultrasound treatment for essential tremor can sometimes cause side effects. These side effects are related to the specific target that we aim focused ultrasound at during treatment, and the deep brain structures that surround the target area.

Accurate targeting is key, since the position and location of the lesion created by the focused ultrasound can affect whether side effects are permanent or transient. If a permanent lesion is placed in a certain structure, the subsequent side effect will also be permanent. However, years of experience and gathering of clinical outcome data means that our neurosurgeons are very good at accurate targeting and avoiding this situation. Developments made in the use magnetic resonance imaging (MRI) to demonstrate and locate deep brain anatomy has made targeting more accurate than ever before, whilst experience from treatment centres across the World has enabled improvements in how the ultrasound energy is delivered to the brain.

Most commonly, side effects of focused ultrasound treatment for essential tremor are transient, or temporary, and relate to the temporary swelling that occurs around the target site. The commonest side effects when treating essential tremor are problems with balance, problems with articulation of speech and problems with tingling, for example in the corner of the mouth or the hand. These side effects are usually transient as the swelling that occurs immediately after the therapy slowly dies down, resulting in the symptoms also receding over time. Based on shared clinical outcome data from treatment sites, problems with balance tend to be most common in the period from the first month to three months after the therapy. However after three months and going up to 12 months , the rate of these problems is much much lower.

With experience, we have improved our targeting and modified how we deliver the ultrasound energy to the brain, so that the chance of therapy causing serious and permanent problems in good hands is around 1 in 100 or less.

Where can I find further information about focused ultrasound treatment for essential tremor?

MR-guided focused ultrasound treatment for essential tremor is now available in Queen Square for private patients. If you are interested in treatment and would like to find out more, please contact our treatment coordinators at

Additional information is also available at

Zrinzo Ludvic

Professor Ludvic Zrinzo
Consultant Neurosurgeon
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