Objective: To identify anatomical regions related to stimulation-induced dyskinesia (SID) following pallidal deep brain stimulation (DBS) in Parkinson’s disease (PD) and to analyze structural and functional connectivity associated with SID.

Background: Pallidal DBS studies in PD patients have shown robust improvement in levodopa-induced dyskinesia. However, Pallidal DBS can worsen or even induce dyskinesia in individual cases, and its pathophysiology remains unclear.

Method: We retrospectively investigated clinical and imaging data of 16 PD patients who experienced SID in the Off-med state during the monopolar review. After localizing the DBS contacts, we analyzed structural and functional connectivity using publicly available human connectome data in combination with a model of the volume of tissue activated (VTA). Each DBS contact was assigned to one of two groups, either producing SID (SID VTA) or those contacts without SID (non-SID VTA). VTAs were also estimated using the optimized DBS settings at approximately six months after implantation (optimized VTA). Structural and functional connectivity differences were compared among the different DBS settings.

Results: SID VTAs were located more dorsally and anteriorly compared with non-SID VTAs and optimized VTAs. SID VTAs were primarily located in the dorsal globus pallidus externus (GPe), and unique voxels for SID were not observed within the globus pallidus internus (GPi) or internal capsule. Compared with non-SID and optimized VTAs, SID VTAs showed significantly different structural and functional connectivity to multiple regions, including the primary motor cortex, premotor cortex, supplementary motor area, prefrontal cortex, STN, and cerebellum. A comparison of the structural connectivity pattern between SID and optimized VTAs revealed a significant positive correlation between SID and connections from the pallidum to the STN via the subthalamic fasciculus (SF). Additionally, SID VTAs revealed lesser structural connectivity to the thalamus through the ansa lenticularis (AL) and greater connectivity to the ventralis oralis anterior nucleus of the thalamus through the fasciculus lenticularis when compared with non-SID VTAs.

Conclusion: SID in this study was associated with stimulation of the pallidal subregions that were connected to the motor-related cortices and STN. The involvement of the AL by DBS may suppress SID.

« Back to MDS Virtual Congress 2020

MDS Abstracts - https://www.mdsabstracts.org/abstract/the-subthalamic-fasciculus-and-connectivity-profiling-of-stimulation-induced-dyskinesia-following-pallidal-dbs-in-parkinsons-disease/