Focused Ultrasound for Parkinson’s and Essential Tremor
Overview of Focused Ultrasound for Essential Tremor and Parkinson’s Disease
Focused ultrasound thalamotomy describes the use of focused waves of sound to treat an area deep in your brain called the thalamus. This procedure can reduce or eliminate symptoms of essential tremor and can help with the tremor symptoms associated with Parkinson’s disease.
In focused ultrasound thalamotomy, sounds waves come from different directions and generate heat at the point where the waves converge. The heat ablates a portion of the thalamus. This prevents the firing of the circuits responsible for essential tremor, thus eliminating or reducing the tremor.
What is a thalamotomy?
A thalamotomy is any procedure that ablates a part of the thalamus. In this context, an ablation refers to using heat for the intentional destruction of tissue for therapeutic purposes.
Thalamotomies have been performed using various techniques for over 50 years to treat essential tremor and parkinsonian tremor. Techniques have included inserting a radiofrequency probe through a hole made in the skull, delivering focused radiation (similar to what is used for some tumors), and, more recently, focused ultrasound.
Focused ultrasound thalamotomy does not require incisions or drilling of the scalp or skull. In addition, the sound waves do not have enough energy to cause damage except at the point where they converge. This means that portions of the brain more than a few millimeters from where the ultrasound is being targeted are not at risk of being damaged.
What is focused ultrasound thalamotomy used for?
Focused ultrasound thalamotomy is used to treat the following:
- Essential tremor
- Parkinson’s tremor
Steps of Focused Ultrasound Treatment for Essential Tremor and Parkinson’s
During this procedure, magnetic resonance imaging (MRI) is used to image the brain, guide the targeting of the ultrasonic waves, and monitor the temperature changes caused by the ultrasound energy.
It will be necessary to shave your scalp for this procedure to ensure that your hair does not interfere with the delivery of the sound waves.
Before the procedure, a stereotactic frame is attached to your head. This ensures that your head does not move during the MRI or as the sound waves are being transmitted. The frame is attached by pressure applied at four sites. Numbing medicine is injected to those four sites using a small needle. You will also take Tylenol, a steroid, and an anti-nausea medication before the procedure to control for symptoms during the procedure.
Because the sound waves can cause to you feel warm, our team will fit you with a cap that will be placed over your head like a headband. This will circulate cold water over your scalp to help you stay comfortable.
You will remain flat on the MRI table for the duration of the procedure, which lasts about two hours. The bed is padded for your comfort. The table will move in and out of the scanner as we image your brain, administer test doses to confirm therapeutic effect and evaluate for side effects, and administer the therapeutic doses.
What to Expect: Side Effects and Recovery
Focused ultrasound thalamotomy is performed without any sedation, meaning you will be awake and alert during the procedure, including the placement of the headframe. Your neurosurgeon will ask you questions and have you perform tasks and movements to ensure the procedure is having the desired effect and to evaluate for side effects.
This is an outpatient procedure, meaning you will go home on the same day as the procedure.
Most people do not report pain during the procedure. Unsteadiness immediately after the procedure is common, and patients are recommended to take precautions not to fall. Many patients bring a walker, cane, or wheelchair to assist with balance after the procedure. Other symptoms may include dizziness, numbness, headache, nausea, or tingling. These effects usually are transient and improve with time.
A short course of steroids is typically prescribed to help with side effects.
There will be four points on your scalp where the pins from the frame were placed – above the eyebrows and behind the ears. Bandages and ointment will be placed on those areas. You may remove these and shower the day after.
You are required to have a companion drive you home after the procedure. You may not drive for two weeks.
Am I a good candidate for focused ultrasound thalamotomy?
You may be a good candidate for focused ultrasound thalamotomy if you meet the following criteria:
- You have been given a diagnosis of essential tremor (ET) or tremor-dominant Parkinson’s disease by a neurologist or movement disorder specialist
- You have tried at least 2 trials of medications including primidone and propranolol
- You have moderate to severe tremor of the dominant hand
- You are not a candidate for DBS (Deep Brain Stimulation) because of advanced age, blood thinners, surgical comorbidities, or you have failed DBS and had the DBS system removed
Who is not a good candidate for focused ultrasound?
You may not be a good candidate for focused ultrasound if any of the following are true:
- You are pregnant
- You have a metal implant, such as a pacemaker, that is not MRI compatible, or metal clips,
neurostimulators, spine or bone fixation devices, and/or total joint replacements that are not MRI compatible
- You are claustrophobic or not able to tolerate being in a stationary position for a prolonged period of time during treatment (approximately 2 hours)
- You have health-related issues such as a recent heart attack, congestive heart failure, unstable chest pain, or a spinal condition
- You have extensive scarring on the scalp or skull tumors
- You have an active infection or any uncontrolled diseases
- You are on dialysis
- You are not able to stop antiplatelet or anticoagulation therapy
What are the benefits of focused ultrasound?
- Focused ultrasound does not require an incision
- It is performed as an outpatient procedure
- You should notice immediate improvement in your tremor; on average patients see a 50-75% improvement in their tremor
What are the possible complications after the procedure?
After undergoing focused ultrasound for Parkinson’s disease or essential tremor, some people may experience:
- Temporary or permanent muscle weakness
- Unsteadiness when walking
- Numbness or tingling in your fingers or other parts of your body
- Nausea or headache
Does my insurance cover a focused ultrasound procedure?
In the State of Arizona, most plans from the following providers cover focused ultrasound for essential tremor:
- Medicare Advantage Plans
- Blue Cross Blue Shield of Arizona
There are fewer plans that cover focused ultrasound for tremor-dominant Parkinson’s disease:
- Medicare Advantage Plans
If you have questions about your health insurance coverage, please call our nurse navigator at (602) 406-3865.
How can I schedule an appointment?
You will need a referral from a neurologist if you would like to be evaluated for focused ultrasound at Barrow Neurological Institute.
Before your appointment, you will need to gather the following items:
- A referral to Barrow for focused ultrasound evaluation
- Your insurance and contact information
- Notes from your last four office visits
- Your tremor rating scale
- A brain MRI or head CT scan if available
If your neurologist has any questions about the referral process, please ask them to call (602) 406-
3865. You can also call this number if you do not have a neurologist and need assistance scheduling an appointment with a movement disorders neurologist at Barrow.