Essential tremor (ET)
Tremor is the most common movement disorder (intention>postural>resting), with essential tremor affecting 5–10 million persons in the U.S. Thalamic stimulation may be useful for tremors that are refractory to medical treatment, including tremor dominant Parkinson's disease, essential tremor, 1), 2) cerebellar and posttraumatic tremor 3). Prior to being considered for surgical intervention, it should be determined that the patient has failed maximal medical therapy. Side effects of Vim stimulation include paresthesias, H/A, dysequilibrium, dysarthria, dystonia & localized pain.
Clinical features
Essential tremor is a nervous system (neurological) disorder that causes involuntary and rhythmic shaking. It can affect almost any part of your body, but the trembling occurs most often in your hands — especially when you do simple tasks, such as drinking from a glass or tying shoelaces.
Treatment
Case series
De Vloo et al. reported on an ET patient who underwent an Magnetic resonance guided focused ultrasound thalamotomy but experienced tremor recurrence. They expanded the MRgFUS-induced thalamic cavity using radiofrequency (RF), with good effect on the tremor but transient sensorimotor deficits and permanent ataxia. This is the first report of a patient undergoing RF thalamotomy after an unsuccessful MRgFUS thalamotomy. As we used microelectrode recording to guide the RF thalamotomy, they could also study for the first time the electrophysiological properties of previously sonicated thalamic neurons bordering the MRgFUS-induced cavity. These neurons displayed electrophysiological characteristics identical to those recorded from nonsonicated thalamic cells in ET patients. Hence, this findings support the widespread assumption that sonication below the necrotic threshold does not permanently alter neuronal function 4).