Cognitive Outcomes of Unilateral Magnetic Resonance-Guided Focused Ultrasound of the Ventral Intermediate Nucleus of the Thalamus for Essential Tremor

Julie Petersen, Harvard Medical School at Beth Israel Deaconess Medical Center, Boston, United States
Joshua McGough, West Virginia University School of Medicine, Morgantown, United States
Ann Murray, West Virginia University School of Medicine, Morgantown, United States
Richa Tripathi, Emory University School of Medicine, Atlanta, United States
Jennifer Rabin, Sunnybrook Research Institute, Toronto, Canada
James Mahoney, West Virginia University School of Medicine, Morgantown, United States
Marc Haut, West Virginia University School of Medicine, Morgantown, United States
Ali Rezai, West Virginia University School of Medicine, Morgantown, United States
David Scarisbrick, West Virginia University School of Medicine, Morgantown, United States


Essential tremor (ET) stands as one of the most prevalent movement disorders, distinguished by a progressive action tremor which can lead to considerable disability. Magnetic Resonance-Guided Focused Ultrasound (MRgFUS), a minimally invasive treatment employing thermal ablation to create precise lesions, has emerged as a technique for addressing refractory essential tremor. The assessment of cognitive change following MRgFUS for ET represents a relatively novel research area, with few existing studies. Often patients are older adults, many of whom report fears of possible cognitive decline. The current study seeks to address this gap in the literature and provide additional information for patients and providers to consider when making informed treatment decisions. To this end, cognitive and motor functions were assessed at baseline and after unilateral MRgFUS targeting the ventral intermediate nucleus (VIM) of the thalamus.

Participants and Methods:

Twenty-two older adults (mean age 73, SD = 8) with medically intractable ET were evaluated at baseline and 6-months following unilateral MRgFUS VIM thalamotomy. All patients were clinically evaluated by movement disorder neurologists, neurosurgeons, physical therapists, and neuropsychologists. The neuropsychological assessment measured performance across the cognitive domains of attention, working memory, processing speed, executive function, verbal fluency, and learning and memory. The physical therapy evaluation measured multiple aspects of motor function, including tremor severity, balance, mobility, and gait. Differences across time were examined using paired t-tests and, when suitable, Wilcoxon signed-rank tests. A Benjamini-Hochberg procedure with a false discovery rate of 0.05 was applied to account for multiple comparisons.


The laterality of MRgFUS was determined to be contralateral to the hand causing the highest degree of functional impairment, resulting in 6 patients receiving MRgFUS VIM thalamotomy in the right hemisphere and 16 patients in the left hemisphere. There were no significant differences between baseline and follow-up neuropsychological assessment performance after correcting for multiple comparisons. Regarding motor function, a Wilcoxon signed-rank test indicated that the tremor severity ranks following MRgFUS VIM thalamotomy were significantly improved from baseline (Z = -3.623, p-corrected = 0.0003). No other motor measures, including those of balance, mobility, and gait, emerged as significantly different across time.


This study presents the first U.S.-based sample to examine the relationship between MRgFUS VIM thalamotomy and cognition in patients with ET. Our investigation revealed that after undergoing unilateral thalamotomy, patients experienced significant relief in tremor severity while simultaneously maintaining cognitive stability across all domains. These findings highlight the effectiveness of unilateral MRgFUS VIM thalamotomy in treating ET and provide reassurance to both patients and healthcare providers regarding cognitive outcomes. Cognitive stability is particularly salient in a clinical population primary composed of older adults, especially for a condition increasingly associated with cognitive impairment in the “ET-plus” literature. Given this importance of clarifying cognitive outcomes following MRgFUS VIM thalamotomy in ET, future prospective studies with larger samples are necessary to confirm the generalizability of current findings. Additionally, future studies should explore cognition following bilateral VIM thalamotomy, which has recently received FDA approval.

Category: Movement and Movement Disorders

Keyword 1: cognitive functioning
Keyword 2: movement disorders
Keyword 3: treatment outcome