2024 American Academy of Neurology Abstract Website

Objective:

To determine the ideal location for deep brain stimulation (DBS) of globus pallidus interna (GPi) in Parkinson’s Disease (PD).

Background:

The clinical success of DBS is dependent on accurate electrode placement and stimulation of a specific region within brain targets including GPi. There is a knowledge gap on location of the ideal stimulation area within GPi, hence identifying this could facilitate DBS programming and improve surgical outcomes.

Design/Methods:

All patients who underwent GPi DBS between 2020-2022 were included in the study and their clinical and imaging data were retrospectively analyzed. Stimulation data at six months post-op was used to generate stimulation field model (SFM) for each lead with Boston Scientific GUIDE™ XT and then aggregated to generate volumetric stimulation heatmaps with BrainLab Quentry® software. Clinical Global Impression-Change (CGI-C) scale was the primary outcome measure, scored according to response in contralateral tremor, rigidity and bradykinesia, and then correlated with SFM to generate ideal locations for stimulation in GPi. The secondary outcome measure was difference in pre- and post-DBS MDS-UPDRS scores.

Results:

Twenty-two PD patients with 36 GPi leads were included in the study. Mean age was 64±8.5 and 67% were male. MDS-UPDRS improved from 33.5 to 19.7 (42%) six months post-op (p=0.0003). For right GPi leads, 11/16 (69%) had CGI-C of 1 (very much improved) and 5/16 (31%) had 2 (much improved). For left GPi leads 13/20 (65%) and 7/20 (35%) had CGI-C of 1 and 2, respectively. We identified the “sweet spot” corresponding with CGI-C of 1 to be in the postero-lateral and middle region of GPi on axial and coronal sequences, respectively.

Conclusions:

In this single-center study we identified that stimulation in the postero-lateral and middle region of GPi resulted in the best clinical outcomes. Our findings support the previously reported, limited evidence in literature and therefore will have important therapeutic implications.