Probabilistic Mapping of Deep Brain Stimulation: Insights from 15 Years of Therapy

Abstract

Deep brain stimulation (DBS) depends on precise delivery of electrical current to target tissues. However, the specific brain structures responsible for best outcome are still debated. We applied probabilistic stimulation mapping to a retrospective, multidisorder DBS dataset assembled over 15 years at our institution (ntotal = 482 patients; nParkinson disease = 303; ndystonia = 64; ntremor = 39; ntreatment‐resistant depression/anorexia nervosa = 76) to identify the neuroanatomical substrates of optimal clinical response. Using high‐resolution structural magnetic resonance imaging and activation volume modeling, probabilistic stimulation maps (PSMs) that delineated areas of above‐mean and below‐mean response for each patient cohort were generated and defined in terms of their relationships with surrounding anatomical structures. Our results show that overlap between PSMs and individual patients' activation volumes can serve as a guide to predict clinical outcomes, but that this is not the sole determinant of response. In the future, individualized models that incorporate advancements in mapping techniques with patient‐specific clinical variables will likely contribute to the optimization of DBS target selection and improved outcomes for patients. ANN NEUROL 2021;89:426–443

Ventral Intermediate Nucleus structural connectivity-derived segmentation: anatomical reliability and variability

“…In the study conducted by Al-Fatly and colleagues structural and functional "therapeutic" connectivity patterns of leads located in close proximity to "classic" coordinates included cerebellum, pre and postcentral gyri, SMA and paracentral lobule; moreover, discriminative fiber tracts connected to VTA, thus being linked with clinical improvement, belong to DRTC tract (Al-Fatly et al, 2019;Baldermann et al, 2019). Similarly, in the study conducted by Elias and collaborators, clinicallyweighted hotspots were connected to precentral gyrus, SMA and prefrontal regions, including again the DRTC (Elias et al, 2020). Herein, we show that the classic stimulation point lies in close proximity to dentate, precentral, SMA and paracentral MPMs.…”

“…In order to investigate if the location of group-level connectivity maps match the stimulation points for essential tremor (ET) available in literature, we calculated Euclidean distances between MPM COGs and three sets of coordinates provided by a recent study (Elias et al, 2020). Specifically, the first set of coordinates was represented by the “classic” literature-based optimal lead location, obtained from 37 patients affected by ET and translated to MNI space using a probabilistic conversion method (Horn et al, 2017; Papavassiliou et al, 2004).…”

“…Beyond comparing the spatial distribution between connectivity-derived maps and anatomy of Vim thalamic nucleus defined as an histological entity, we also investigated the spatial relations of the group-level connectivity maps with higher similarity to Vim with three different, group-level coordinates of optimal stimulation points for ET, which have been recently provided in a study conducted on implanted patients (Elias et al, 2020) (Figure 8). Specifically, the first stimulation site consisted of the "classic" electrode location, commonly used to guide stereotactic neurosurgery of tremor (Horn et al, 2017;Papavassiliou et al, 2004), whilst the second and the third sets of coordinates have been obtained from probabilistic stimulation mapping (PSM) of volume of tissue activated (VTA), representing the most commonly stimulated voxels in the cohort (clinically unweighted maps) and clinically-weighted hotspots (zones where stimulation produced above-mean clinical improvements) respectively (Elias et al, 2020). "Classic" coordinates of electrode location were located in the ventral-most part of thalamus, just adjacent to dentate and precentral maps; such position likely represents the best match to the classic localization of Vim, as described in anatomical studies (Asanuma et al, 1983c(Asanuma et al, , 1983a.…”

An exploratory study into the influence of laterality and location of hippocampal sclerosis on seizure prognosis and global cortical thinning

“…Greater seizure severity may be related to greater brain-wide connectivity of the seizure focus. Because the patient's included in our study did not have native functional imaging acquisitions, patterns of functional connectivity associated with seizure focus laterality were explored using an established functional connectivity mapping method that has been leveraged in numerous previous studies [19][20][21][22][23] . This method uses a large-scale, high-quality normative resting-state fMRI (rsfMRI) dataset constructed from 1000 healthy subjects (http://neuro infor matic s.harva rd.edu/gsp).…”

“…This method uses a large-scale, high-quality normative resting-state fMRI (rsfMRI) dataset constructed from 1000 healthy subjects (http://neuro infor matic s.harva rd.edu/gsp). Detailed information about the preprocessing and aggregation of this dataset have been previously described [18][19][20][21][22][23][24] . Briefly, each healthy subject in the normative dataset was scanned once or twice (1.7 times per subject on average) with a 6.2 min-long echo-planar imaging sequence (124 time points; 3 × 3 × 3 voxel size, TR 3000 ms, TE 30 ms, flip angle 85°) in order to acquire rsfMRI data.…”