Objective: The objective of the study was to elucidate the neuropsychological outcomes in executive functioning for patients with essential tremor undergoing bilateral MRI guided Focused Ultrasound (MRgFUS) VIM thalamotomy.

Background: Prior studies have examined cognitive outcomes after unilateral MRgFUS for treatment of essential tremor, with minimal cognitive changes post intervention^1,2. However, other thalamotomy and deep brain stimulation approaches have been shown to have negative effects on executive functions (EF), including verbal fluency and working memory^2,3, and no studies have evaluated cognitive outcomes after bilateral VIM MRgFUS.

Method: This was a retrospective analysis including 8 adult essential tremor patients. Pre and post MRgFUS assessments were performed, including tests of working memory (Digit Span) and verbal fluency (both phonemic & semantic stimuli) preoperatively and postoperatively (M_follow-up = 14.5 months). The sample consisted of right-handed, older (M_age =73 (SD=9.05), highly educated (83% bachelor’s or higher), mostly male (59%) and non-Hispanic White (83%) individuals. Raw and normatively scaled scores were compared with paired t-tests and Wilcoxon signed-rank tests.

Results: There were no statistically significant differences in mean verbal fluency for phonemic nor semantic stimuli, for neither raw nor normative scores after MRgFUS. There was an improvement in working memory performance in both raw and normative scores (pre ss = 9.1, post-ss = 10.9, p = .002, d = 1.7, 95% CI [0.6, 2.8]).

Conclusion: Overall, results showed that patients with ET do not experience significant cognitive decline within the domains of verbal fluency after bilateral MRgFUS of VIM. Furthermore, patients may experience an improvement in working memory.

References: Bucur M, Papagno C. Deep Brain Stimulation in Parkinson Disease: A Meta-analysis of the
Long-term Neuropsychological Outcomes [published online ahead of print, 2022 Mar 23]. Neuropsychol Rev. 2022;10.1007/s11065-022-09540-9. doi:10.1007/s11065-022-09540-9.

Rohringer CR, Sewell IJ, Gandhi S, et al. Cognitive effects of unilateral thalamotomy for tremor:
a meta-analysis. Brain Commun. 2022;4(6):fcac287. Published 2022 Nov 4. doi:10.1093/braincomms/fcac287.

Saporito, G., Sucapane, P., Ornello, R., Cerone, D., Bruno, F., Splendiani, A., … & Pistoia, F.
(2023). Cognitive outcomes after focused ultrasound thalamotomy for tremor: Results from the COGNIFUS (COGNitive in Focused UltraSound) study. Parkinsonism & Related Disorders, 106, 105230.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/neuropsychological-outcomes-after-bilateral-focused-ultrasound-thalamotomy-within-essential-tremor/