Deep Brain Stimulation: Imaging on a group level

Abstract

Highlights We present a novel toolbox to carry out DBS imaging analyses on a grouplevel  Group electrodes are visualized in 2D and 3D and related to clinical regressors  A favorable target and connectivity profiles for the treatment of PD are validated Abstract Deep Brain Stimulation (DBS) is an established treatment option for movement disorders and is investigated to treat a growing number of other brain disorders. It has been shown that DBS effects are highly dependent on exact electrode placement, which is especially important when probing novel indications or stereotactic targets. Thus, considering precise electrode placement is crucial when investigating efficacy of DBS targets. To measure clinical improvement as a function of electrode placement, neuroscientific methodology and specialized software tools are needed. Such tools should have the goal to make electrode placement comparable across patients and DBS centers, and include statistical analysis options to validate and define optimal targets. Moreover, to allow for comparability across different research sites, these need to be performed within an algorithmically and anatomically standardized and openly available group space. With the publication of Lead-DBS software in 2014, an open-source tool was introduced that allowed for precise electrode reconstructions based on pre-and postoperative neuroimaging data. Here, we introduce Lead Group, implemented within the Lead-DBS environment and specifically designed to meet aforementioned demands. In the present article, we showcase the various processing streams of Lead Group in a retrospective cohort of 51 patients suffering from Parkinson's disease, who were implanted with DBS electrodes to the subthalamic nucleus (STN). Specifically, we demonstrate various ways to visualize placement of all electrodes in the group and map clinical improvement values to subcortical space. We do so by using active coordinates and volumes of tissue activated, showing converging evidence of an optimal DBS target in the dorsolateral STN. Second, we relate DBS outcome to the impact of each electrode on local structures by measuring overlap of stimulation volumes with the STN. Finally, we explore the software functions for connectomic mapping, which may be used to relate DBS outcomes to connectivity estimates with remote brain areas. We isolate a specific fiber bundlewhich structurally resembles the hyperdirect pathwaythat is associated with good clinical outcome in the cohort.The manuscript is accompanied by a walkthrough tutorial through which users are able to reproduce all main results presented in the present manuscript. All data and code needed to reproduce results are openly available.

StimVision v2: Examples and Applications in Subthalamic Deep Brain Stimulation for Parkinson’s Disease

“…Given the very small region of interest for subthalamic DBS (i.e., ~6 × 6 × 6 mm 3 ) (36,37), the uncertainties associated with DBS modeling call into question the legitimacy of performing correlative analyses between generic UPDRS‐III scores and simple VTA models mapped into an atlas space (45,46). Therein lies our motivation to improve the anatomical and electrical accuracy of connectomic DBS modeling with the technical advances implemented in StimVision v2.…”

“…This assumption may be reasonable for a simple and quantifiable behavioral metric (e.g., reduction of tremor via DBS of the cerebellothalamic pathway), but is likely to be unreasonable for a complex clinical outcome score. The patient-specific DBS modeling results of Figure 4 provide some insight into why recent attempts to correlate UPDRS-III scores with simple DBS models have had such limited success (45,46). One issue is the diversity of axonal pathways that are simultaneously activated during therapeutic DBS.…”

Ventral Capsule/Ventral Striatum Stimulation in Obsessive-Compulsive Disorder: Toward a Unified Connectomic Target for Deep Brain Stimulation?

“…R-values were corrected for the stimulation amplitude. Validation of the tracts was sought by performing a k-fold cross prediction (28,30).…”

A Randomised, Double-Blind, Sham-Controlled Trial of Deep Brain Stimulation of the Bed Nucleus of the Stria Terminalis for Treatment-Resistant Obsessive-Compulsive Disorder

“…The use of normative rather than participant-specific connectivity data is a further limitation and has been discussed elsewhere (Coenen et al, 2019;Li et al, 2019;Treu et al, 2020).…”