Objective: To analyze the pathophysiology of dystonic tremor (DT) and essential tremor (ET) and to reveal the optimal deep brain stimulation (DBS) target for these disorders using volumes of tissue activated estimation and connectivity analysis.
Background: Similarities and differences in the pathophysiology between dystonic tremor and essential tremor have been revealed in recent studies. DBS may be a promising treatment option for patients with medication-refractory DT or ET; however, the optimal DBS target for these disorders remains unclear.
Method: We included 20 DT patients who underwent unilateral thalamic DBS and a matched cohort of 20 ET patients. Tremor severity was assessed before and after surgery using the Fahn-Tolosa-Marin tremor rating scale (TRS). The tremor-suppressing effects of DBS were estimated using the percentage improvement in the unilateral TRS score contralateral to the side of implantation.
Results: Results: The optimal stimulation region for ET was in the ventral intermediate nucleus (VIM), and for DT in the ventralis oralis posterior nucleus (VOp). Both disorders showed similar functional connectivity patterns: a positive correlation between tremor improvement and the involvement of the motor and prefrontal regions. Tremor improvement, however, was more tightly correlated with the primary motor region in ET whereas in DT the correlation was tighter with the premotor and prefrontal regions. The dentato-rubro-thalamic tract significantly correlated with tremor improvement in both DT and ET. In contrast, the pallido-thalamic tracts, which primarily project to the VOp, significantly correlated with tremor improvement only in DT.
Conclusion: Our findings support the hypothesis that the pathophysiology of DT involves both the cerebellothalamocortical network and the basal ganglia-thalamocortical network and that the pathophysiology of essential tremor is attributable to the cerebellothalamocortical network. VIM/VOp border and VIM may be a reasonable DBS target for patients with DT and essential tremor, respectively.
To cite this abstract in AMA style:
T. Tsuboi, J. Wong, R. Eisinger, L. Okromelidze, M. Burns, A. Ramirez-Zamora, L. Almeida, A. Wagle Shukla, K. Foote, M. Okun, S. Grewal, M. Katsuno, E. Middlebrooks. Comparative connectivity correlates of dystonic and essential tremor deep brain stimulation [abstract]. Mov Disord. 2021; 36 (suppl 1). https://www.mdsabstracts.org/abstract/comparative-connectivity-correlates-of-dystonic-and-essential-tremor-deep-brain-stimulation/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2021
MDS Abstracts - https://www.mdsabstracts.org/abstract/comparative-connectivity-correlates-of-dystonic-and-essential-tremor-deep-brain-stimulation/