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Dr. Marc Lévêque (Neurosurgery – Pain)
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February 24, 2023
A new “focused ultrasound” treatment dramatically improves tremors and other symptoms associated with Parkinson’s disease. What is the role of this non-invasive alternative to deep brain stimulation?
This is good news for all Parkinson’s patients. A device, called Exablate Neuro, would improve the symptoms of the disease in a non-invasive way and without anesthesia or hospitalization. The results of this trial were published in the New England Journal of Medicine.
Parkinson’s disease: an alternative to deep brain stimulation
Parkinson’s disease is a neurodegenerative disease that affects brain cells or neurons in a specific area of the brain that produce dopamine. Symptoms include tremors, stiffness, and difficulty with balance and coordination. Other treatments for Parkinson’s disease include medications and deep brain stimulation (DBS) from surgically implanted electrodes.
Medications can cause involuntary, erratic movements called dyskinesia when doses are increased to control symptoms.
Usually offered when medication fails, DBS involves brain surgery to insert electrodes through two small openings in the skull. The procedure carries a low risk of serious side effects, including brain hemorrhage and infection. But as part of this trial, the researchers tested a less invasive technique based on ultrasound.
Better motor skills and reduced dyskinesia
Focused ultrasound is an incisionless procedure, performed without anesthesia or hospitalization. The patients, who remain fully conscious, lie in a magnetic resonance imaging (MRI) scanner, wearing a transducer headset. Ultrasonic energy is targeted through the skull to the globus pallidus, a structure deep in the brain that helps control regular voluntary movements. MRI images provide doctors with a real-time temperature map of the treated area, to precisely locate the target and apply a temperature high enough to destroy it. During the procedure, the patient is awake and provides feedback, allowing doctors to monitor the immediate effects of tissue removal and make any necessary adjustments.
To evaluate this technique, researchers at the University of Maryland School of Medicine (UMSOM) randomly assigned 94 patients with Parkinson’s disease to two groups.
- The first group – consisting of 69 patients – was to test the famous ultrasound device capable of focusing to the point of removing a very targeted part of one side of the brain (which controlled the side of their body where the symptoms were the most severe). ,
- The other group – made up of 25 patients – was to undergo a sham procedure.
A total of 65 patients and 22 patients, respectively, completed the evaluation of the first tests.
Result ? Those in the first group showed an immediate improvement of at least three points on a standard assessment – measuring tremor, walking ability and leg and arm stiffness – compared to a 0.3 point improvement in the group witness.
The first group also noted a marked improvement in the side effects caused by the drugs.
On the other hand, certain undesirable events resulting from the procedure were recorded. These were mainly headaches, dizziness and nausea, all of which disappeared within a day or two of treatment.
Some patients in the first group also presented with slurred speech, walking problems and loss of taste. But these mild side effects of the treatment disappeared within a few weeks.
For researchers,unilateral pallidal ultrasound ablation“therefore remains an encouraging therapeutic avenue.
“These results are very promising and offer patients with Parkinson’s disease a new form of therapy to manage their symptoms. There is no incision involved, which means there is no risk of serious infection or brain hemorrhage“, said the study’s corresponding author, Howard Eisenberg, MD.
A less expensive and non-radioactive technique
For Dr. Marc Leveque, neurosurgeon and pain specialist, it is a competing technique of radiosurgery, which has advantages but also some disadvantages.
“This ultrasound-based procedure is promising for several reasons: it does not use radiation, is less expensive, and can be used in patients for whom brain stimulation is contraindicated. It may therefore be required to replace the Gamma Knife tool, used in radiosurgery. However, it is a little less precise. It is therefore necessary, in my opinion, to carry out comparative studies on these different techniques before drawing conclusions..