When considering focused ultrasound treatment (FUS) for essential tremor (ET), there are some questions about what to expect not only during the procedure, but after. Since anticipating any medical treatment can be overwhelming, let’s talk about what to expect – even after the procedure is completed.

Like any medical treatment, focused ultrasound has the potential for side effects. While every person is different in their reaction to any procedure, you should talk to your physician prior to MRI-guided focused ultrasound treatment regarding the safety risks and benefits to see if it is right for you.

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What to Expect Immediately After Focused Ultrasound Treatment?

During and immediately after treatment, improvements are usually noticeable in hand tremors. Because there are no incisions, there is low-to-no risk of infection, and patients can plan to return home the same day of treatment.

The most common side effects or adverse events reported by patients in Insightec-sponsored clinical studies included mostly transient symptoms such as headache/head pain (51% of study patients), numbness/tingling (33%) and imbalance/gait disturbance (26%).

Most side effects were reported as mild or moderate in severity, with symptoms typically improving within a few days or months.

What to Expect One Day to Two Weeks After FUS Treatment?

Some patients reported numbness or tingling in their fingertips or lips on the side of treatment. This may be due to swelling (a normal response) of the treated area, also called the Vim of the thalamus, and is next to the area of the brain that affects sensations of the hands and face. The sensations tend to be mild and temporary. That said, in 10-15% of cases, the sensations could be permanent.1

Some patients also reported feeling unsteady on their feet after the procedure. While this typically only lasts the first or second week after the procedure, patients should still consider using a walker and avoid operating a vehicle for those first weeks after treatment. In Insightec-sponsored clinical studies, longer term unsteadiness was reported in up to 10% of the patients.

In Insightec-sponsored clinical studies, most side effects were classified as mild or moderate, and 48% resolved on their own within 30 days. Additional infrequent events reported included dizziness, taste disturbance, weakness, slurred speech, fatigue and vomiting. There were no reports of infection or seizures. You can read more about the clinical studies here for additional details.

As with any medical procedure, patients should return to activities gradually. In most cases, they are able to return to daily activities within days. That means relief from essential tremor symptoms, going back to work, resuming hobbies, and spending time with family and friends.

As with any surgical procedure, a follow-up appointment should be planned with the primary care physician, neurologist, or movement disorder specialist to discuss the treatment as well as any potential side effects.

What to Expect Six Months to Three Years After FUS Treatment?

Some patients experience persistent complications following focused ultrasound treatment. In Insightec-sponsored clinical studies, persistent complications at three-year follow-ups included numbness/tingling (9% of study patients), imbalance (4%), unsteadiness (4%), gait disturbance (2%), and musculoskeletal weakness (2%).

What to Expect After Second-Side FUS Treatment?

Where in the past, patients could only get one side of their brain treated, today many are moving forward treating the other side as well. The most common side effects reported in an Insightec-sponsored clinical trial after second-side treatment included numbness/tingling (31% of study patients), slurred speech (29%), and ataxia (23%). About half of these side effects were ongoing six months after second-side treatment, but more than 95% of them were mild in nature.

The most common side effects six months after second-side focused ultrasound treatment for essential tremor included numbness/tingling (16% of study patients), slurred speech (14%), ataxia (14%), hypogeusia (8%), dysphagia (8%), and dysgeusia (6%). Most of these side effects remained mild in nature.

Taking this essential tremor quiz and sharing results with a treating physician can help to determine if focused ultrasound is the right option for you.


  • common side effects
  • deep brain stimulation
  • Focused ultrasound side effects
  • magnetic resonance imaging
  • minimal side effects
  • quality of life
  • treatment options

Cyril Ferrer, PhD, Medical Science Liaison

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