Ultrasound thalamotomy effective in treating bilateral essential tremor: JAMA

A new study conducted by Michael Kaplitt and team found that both the functional impairment ratings and the intensity of the tremor were dramatically decreased by staged, bilateral focused ultrasound thalamotomy. The findings of this study were published in the Journal of American Medical Association.

While untreated contralateral or midline symptoms may still be limiting for certain individuals, unilateral magnetic resonance-guided targeted ultrasound ablation of the ventralis intermedius nucleus of the thalamus for vital tremor lowers tremor on one side. In the past, deep brain stimulation replaced bilateral lesioning due to its unacceptably high hazards and now, as unilateral targeted ultrasound lesioning becomes more widely accepted, interest in a bilateral alternative is growing. Thus, this study was to assess the safety and effectiveness of bilateral focused ultrasound thalamotomy that is performed in stages.

The patients with essential tremor were treated in this study at 7 US academic medical institutions from July 2020 to October 2021, with a 12-month follow-up. 11 individuals were eliminated, and 51 received treatment out of the 62 recruited patients who had undergone unilateral focused ultrasound thalamotomy at least nine months before inclusion. The patient age, drug resistance, the severity of the tremor, and functional handicap were all requirements for eligibility. Real-time alignment of thermography maps with anatomy was made possible by a focused ultrasound device that interfaced with magnetic resonance imaging. Prior to inducing an ablation, subthreshold sonications enabled target inquiry for effectiveness and off-target consequences.

There were 44 participants (86.3%) who were male, and the population's mean (SD) age was 73 (13.9) years. After 3 months, the mean (SD) tremor/motor score decreased from 17.4 to 6.4. Also, the mean (SD) disability score and mean (SD) postural tremor were significantly improved. 12 individuals experienced moderate ataxia (as determined by the research), which remained in 6 at the 12-month mark.

Numbness/tingling (n = 17 total; n = 8 at 12 months), dysarthria (n = 15 total; n = 7 at 12 months), ataxia (n = 12 total; n = 6 at 12 months), unsteadiness/imbalance (n = 10 total; n = 0 at 12 months), and taste disturbance (n = 7 total; n = 3 at 12 months) were the most frequently reported adverse events. Articulation, phonation, and dysphagia were among the speech difficulties that were often minor and temporary. Overall, staged bilateral MRgFUS thalamotomy considerably lowered tremor severity and functional impairment ratings where speech, swallowing, and ataxia-related adverse effects were mainly moderate and temporary.

Source:

Kaplitt, M. G., Krishna, V., Eisenberg, H. M., Elias, W. J., Ghanouni, P., Baltuch, G. H., Rezai, A., Halpern, C. H., Dalm, B., Fishman, P. S., Buch, V. P., Moosa, S., Sarva, H., & Murray, A. M. (2024). Safety and Efficacy of Staged, Bilateral Focused Ultrasound Thalamotomy in Essential Tremor. In JAMA Neurology. American Medical Association (AMA). https://doi.org/10.1001/jamaneurol.2024.2295