Category: Surgical Therapy: Parkinson's Disease
Objective: Programming approach to optimize outcomes in PD patients implanted in GPi with directional DBS systems and to analyze volumes of tissue activation (VTAs) in GPi. To calculate power using impedance data.
Background: STN and GPi have been shown to be effective DBS targets for treatment of advanced PD. Studies indicate that stimulation of GP as a whole has robust effect on bradykinesia. However, unless DBS lead is placed proximal to border of GPe and GPi, it may not be possible to stimulate GP as a whole using non-directional stimulation without stimulating neighboring structures. In this work, we report using directional DBS in GP.
Method: During monopolar review, we tested non-directional and directional electrode montages to determine optimum therapeutic-window (TW). We refer to co-activation of single-segments aligned in same direction from two segmented levels as V-SSA. VTA analysis was done using Sim4Life v4.0 and the MIDA model. Power was calculated using impedance data
Results: Review of clinical settings of 7 GPi-DBS implantations in 4 PD patients optimized for outcomes and TW revealed that V-SSA was used in 6 out of 7 implants. For these implants, mean and median VTA overlaps with GP were 89% (±12%) and 93%, respectively. Mean and median of ratio of VTAs in GPe to GPi were 5.75 (±11.08) and 1.3, respectively. The mean settings were 2.67 mA at 67 µs and 153 Hz. The implant that was not on V-SSA was on a complex bipolar-montage with only 60% of its VTA in GP. It had a ratio of VTA in GPe to GPi of 0.5 and settings of 2.1 mA at 150 µs (2.25 times that for V-SSA leads) and 180 Hz.
Power calculation using impedance data to be provided during poster/platform presentation. We intend to include additional subjects in this small case series during poster/platform presentation.
Conclusion: Our results suggest that V-SSA may optimize therapy while focusing activation volumes to within GP. Consistent with some earlier work with non-directional leads, optimal stimulation region may not necessarily be restricted to GPi but some combination of GPe and GPi.
References: Power calculation using impedance data to be provided during poster/platform presentation. We intend to include additional subjects in this small case series during poster/platform presentation. References, tables, pictures of lead implantation and Images to be provided during poster/platform presentation
To cite this abstract in AMA style:
M. Anjum, Y. Torres-Yaghi, C. Kalhorn, F. Amjad, A. Carwin, I. Fayed, S. Pallavaram, D. Zhang, F. Pagan. Vertically-Stacked Single Segment Activation (VSSA) as a Programming Approach for Directional DBS in Globus Pallidus Internus (GPi) in Parkinson’s Disease (PD) Patients: First Clinical Case Series [abstract]. Mov Disord. 2020; 35 (suppl 1). https://www.mdsabstracts.org/abstract/vertically-stacked-single-segment-activation-vssa-as-a-programming-approach-for-directional-dbs-in-globus-pallidus-internus-gpi-in-parkinsons-disease-pd-patients-first-clinical-case-se/. Accessed June 15, 2025.« Back to MDS Virtual Congress 2020
MDS Abstracts - https://www.mdsabstracts.org/abstract/vertically-stacked-single-segment-activation-vssa-as-a-programming-approach-for-directional-dbs-in-globus-pallidus-internus-gpi-in-parkinsons-disease-pd-patients-first-clinical-case-se/