Objective: This study aims to use connectomic analysis to determine the difference between fiber pathway activation in patients with ineffective VIM stimulation and effective VIM/VO (ventralis oralis) stimulation.
Background: Deep Brain Stimulation (DBS) is an effective and accepted treatment for medically refractory Essential Tremor (ET). Patients that have ventralis intermedius (VIM) DBS placed for tremor sometimes experience loss of efficacy despite chronic VIM stimulation. These is a constant debate regarding whether this is due to suboptimally placed leads or due to disease progression.
Method: 26 ET patients have been revised with dual thalamic leads at UF. Preoperative CT scans were coregistered to preoperative MRIs, then normalized into MNI space. Lead localization was completed using Lead-DBS. Volumes of Tissue Activation (VTAs) were estimated using finite-element modeling in lead-DBS. Voxel-wise analysis was completed of the pre- and post-revision VTAs, then used as seeds to calculate structural connectivity using deterministic tractography.
Results: 16 total patients were included after having all required data for analysis. The average improvement in TRS score from preop to after VIM/VO revision at 2 years was 18.6 (41%). The Center of Gravity measurement for the pre-revision VTAs was found to be (-15.0, -14.6, 5.4) and post-revision VTAs was found to be (-14.2, -14.9, 2.4). The connectivity strength to the primary motor cortex was stronger in the pre-revision group, whereas the post-revision group had greater connectivity to the supplemental motor area (SMA) (p = 0.04).
Conclusion: This is the first study showing dual thalamic DBS with improved coverage of fibers connected to the SMA leading to improved tremor control in refractory ET patients. Future directions include prospectively targeting VIM/VO leads using DTI tractography from preoperative MRI, in efforts to more strongly influence the SMA.
To cite this abstract in AMA style:
V. Chandra, J. Wong, J. Hilliard, K. Foote, A. Fusco, Y. Mekri. Connectomics of Chronic VIM vs Rescue VIM/VO Deep Brain Stimulation in Essential Tremor [abstract]. Mov Disord. 2023; 38 (suppl 1). https://www.mdsabstracts.org/abstract/connectomics-of-chronic-vim-vs-rescue-vim-vo-deep-brain-stimulation-in-essential-tremor/. Accessed June 15, 2025.« Back to 2023 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/connectomics-of-chronic-vim-vs-rescue-vim-vo-deep-brain-stimulation-in-essential-tremor/