The Fast Gray Matter Acquisition T1 Inversion Recovery Sequence in Deep Brain Stimulation: Introducing the Rubral Wing for Dentato-Rubro-Thalamic Tract Depiction and Tremor Control.

BACKGROUND: The dentato-rubro-thalamic tract (DRT) is currently considered as a potential target in deep brain stimulation (DBS) for various types of tremor. However, tractography depiction can vary depending on the included brain regions. The fast gray matter acquisition T1 inversion recovery (FGATIR) sequence, with excellent delineation of gray and white matter, possibly provides anatomical identification of rubro-thalamic DRT fibers. OBJECTIVE: This study aimed to evaluate the FGATIR sequence by comparison with DRT depiction, electrode localization, and effectiveness of DBS therapy. MATERIALS AND METHODS: In patients with DBS therapy because of medication-refractory tremor, the FGATIR sequence was evaluated for depiction of the thalamus, red nucleus (RN), and rubro-thalamic connections. Deterministic tractography of the DRT, electrode localization, and tremor control were compared. The essential tremor rating scale was used to assess (hand) tremor. Tremor control was considered successful when complete tremor suppression (grade 0) or almost complete suppression (grade 1) was observed. RESULTS: In the postoperative phase, we evaluated 14 patients who underwent DRT-guided DBS: 12 patients with essential tremor, one with tremor-dominant Parkinson disease, and one with multiple sclerosis, representing 24 trajectories. Mean follow-up was 11.3 months (range 6-19 months). The FGATIR sequence provided a clear delineation of a hypointense white matter tract within the hyperintense thalamus. In coronal plane, this tract was most readily recognizable as a "rubral wing," with the round RN as base and lateral triangular convergence. The deterministic DRT depiction was consistently situated within the rubral wing. The number of active contacts located within the DRT (and rubral wing) was 22 (92%), of which 16 (73%) showed successful tremor control. CONCLUSIONS: The FGATIR sequence offers visualization of the rubro-thalamic connections that form the DRT, most readily recognizable as a "rubral wing" in coronal plane. This sequence contributes to tractographic depiction of DRT and provides a direct anatomical DBS target area for tremor control.

Evaluating and Optimizing Dentato-Rubro-Thalamic-Tract Deterministic Tractography in Deep Brain Stimulation for Essential Tremor.

BACKGROUND: Dentato-rubro-thalamic tract (DRT) deep brain stimulation (DBS) suppresses tremor in essential tremor (ET) patients. However, DRT depiction through tractography can vary depending on the included brain regions. Moreover, it is unclear which section of the DRT is optimal for DBS. OBJECTIVE: To evaluate deterministic DRT tractography and tremor control in DBS for ET. METHODS: After DBS surgery, DRT tractography was conducted in 37 trajectories (20 ET patients). Per trajectory, 5 different DRT depictions with various regions of interest (ROI) were constructed. Comparison resulted in a DRT depiction with highest correspondence to intraoperative tremor control. This DRT depiction was subsequently used for evaluation of short-term postoperative adverse and beneficial effects. RESULTS: Postoperative optimized DRT tractography employing the ROI motor cortex, posterior subthalamic area (PSA), and ipsilateral superior cerebellar peduncle and dentate nucleus best corresponded with intraoperative trajectories (92%) and active DBS contacts (93%) showing optimal tremor control. DRT tractography employing a red nucleus or ventral intermediate nucleus of the thalamus (VIM) ROI often resulted in a more medial course. Optimal stimulation was located in the section between VIM and PSA. CONCLUSION: This optimized deterministic DRT tractography strongly correlates with optimal tremor control. This technique is readily implementable for prospective evaluation in DBS target planning for ET.

General Anesthesia vs Local Anesthesia in Microelectrode Recording-Guided Deep-Brain Stimulation for Parkinson Disease: The GALAXY Randomized Clinical Trial.

Importance: It is unknown if there is a difference in outcome in asleep vs awake deep brain stimulation (DBS) of the subthalamic nucleus for advanced Parkinson disease. Objective: To determine the difference in adverse effects concerning cognition, mood, and behavior between awake and asleep DBS favoring the asleep arm of the study. Design, Setting, and Participants: This study was a single-center prospective randomized open-label blinded end point clinical trial. A total of 187 persons with Parkinson disease were referred for DBS between May 2015 to March 2019. Analysis took place from January 2016 to January 2020. The primary outcome follow-up visit was conducted 6 months after DBS. Interventions: Bilateral subthalamic nucleus DBS was performed while the patient was asleep (under general anesthesia) in 1 study arm and awake in the other study arm. Both arms of the study used a frame-based intraoperative microelectrode recording technique to refine final target placement of the DBS lead. Main Outcomes and Measures: The primary outcome variable was the between-group difference in cognitive, mood, and behavioral adverse effects as measured by a composite score. The secondary outcomes included the Movement Disorders Society Unified Parkinson's Disease Rating Scale, the patient assessment of surgical burden and operative time. Results: A total of 110 patients were randomized to awake (local anesthesia; n = 56; mean [SD] age, 60.0 (7.4) years; 40 [71%] male) or to asleep (general anesthesia; n = 54; mean [SD] age, 61.3 [7.9] years; 38 [70%] male) DBS surgery. The 6-month follow-up visit was completed by 103 participants. The proportion of patients with adverse cognitive, mood, and behavioral effects on the composite score was 15 of 52 (29%) after awake and 11 of 51 (22%) after asleep DBS (odds ratio, 0.7 [95% CI, 0.3-1.7]). There was no difference in improvement in the off-medication Movement Disorders Society Unified Parkinson's Disease Rating Scale Motor Examination scores between groups (awake group: mean [SD], -27.3 [17.5] points; asleep group: mean [SD], -25.3 [14.3] points; mean difference, -2.0 [95% CI, -8.1 to 4.2]). Asleep surgery was experienced as less burdensome by patients and was 26 minutes shorter than awake surgery. Conclusions and Relevance: There was no difference in the primary outcome of asleep vs awake DBS. Future large randomized clinical trials should examine some of the newer asleep based DBS technologies because this study was limited to frame-based microelectrode-guided procedures. Trial Registration: trialregister.nl Identifier: NTR5809.

International Multicenter Analysis of Brain Structure Across Clinical Stages of Parkinson's Disease.

BACKGROUND: Brain structure abnormalities throughout the course of Parkinson's disease have yet to be fully elucidated. OBJECTIVE: Using a multicenter approach and harmonized analysis methods, we aimed to shed light on Parkinson's disease stage-specific profiles of pathology, as suggested by in vivo neuroimaging. METHODS: Individual brain MRI and clinical data from 2357 Parkinson's disease patients and 1182 healthy controls were collected from 19 sources. We analyzed regional cortical thickness, cortical surface area, and subcortical volume using mixed-effects models. Patients grouped according to Hoehn and Yahr stage were compared with age- and sex-matched controls. Within the patient sample, we investigated associations with Montreal Cognitive Assessment score. RESULTS: Overall, patients showed a thinner cortex in 38 of 68 regions compared with controls (dmax  = -0.20, dmin  = -0.09). The bilateral putamen (dleft  = -0.14, dright  = -0.14) and left amygdala (d = -0.13) were smaller in patients, whereas the left thalamus was larger (d = 0.13). Analysis of staging demonstrated an initial presentation of thinner occipital, parietal, and temporal cortices, extending toward rostrally located cortical regions with increased disease severity. From stage 2 and onward, the bilateral putamen and amygdala were consistently smaller with larger differences denoting each increment. Poorer cognition was associated with widespread cortical thinning and lower volumes of core limbic structures. CONCLUSIONS: Our findings offer robust and novel imaging signatures that are generally incremental across but in certain regions specific to disease stages. Our findings highlight the importance of adequately powered multicenter collaborations. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

International Parkinson and movement disorder society evidence-based medicine review: Update on treatments for the motor symptoms of Parkinson's disease.

OBJECTIVE: The objective of this review was to update evidence-based medicine recommendations for treating motor symptoms of Parkinson's disease (PD). BACKGROUND: The Movement Disorder Society Evidence-Based Medicine Committee recommendations for treatments of PD were first published in 2002 and updated in 2011, and we continued the review to December 31, 2016. METHODS: Level I studies of interventions for motor symptoms were reviewed. Criteria for inclusion and quality scoring were as previously reported. Five clinical indications were considered, and conclusions regarding the implications for clinical practice are reported. RESULTS: A total of 143 new studies qualified. There are no clinically useful interventions to prevent/delay disease progression. For monotherapy of early PD, nonergot dopamine agonists, oral levodopa preparations, selegiline, and rasagiline are clinically useful. For adjunct therapy in early/stable PD, nonergot dopamine agonists, rasagiline, and zonisamide are clinically useful. For adjunct therapy in optimized PD for general or specific motor symptoms including gait, rivastigmine is possibly useful and physiotherapy is clinically useful; exercise-based movement strategy training and formalized patterned exercises are possibly useful. There are no new studies and no changes in the conclusions for the prevention/delay of motor complications. For treating motor fluctuations, most nonergot dopamine agonists, pergolide, levodopa ER, levodopa intestinal infusion, entacapone, opicapone, rasagiline, zonisamide, safinamide, and bilateral STN and GPi DBS are clinically useful. For dyskinesia, amantadine, clozapine, and bilateral STN DBS and GPi DBS are clinically useful. CONCLUSIONS: The options for treating PD symptoms continues to expand. These recommendations allow the treating physician to determine which intervention to recommend to an individual patient. © 2018 International Parkinson and Movement Disorder Society.

Substituting the Target After Unsatisfactory Outcome of Deep Brain Stimulation in Advanced Parkinson's Disease: Cases From the NSTAPS Trial and Systematic Review of the Literature.

BACKGROUND: Deep brain stimulation (DBS) of the globus pallidus pars interna (GPi) and the subthalamic nucleus (STN) are established treatment option in Parkinson's disease (PD). If DBS does not provide the desired effect, re-operation to the alternative target is a treatment option, but data on the effect of re-operation are scarce. OBJECTIVES: The objective of this study is to evaluate the clinical effect of re-operation the alternative target after failure of initial STN or GPi DBS for Parkinson's disease. MATERIALS AND METHODS: We descriptively analyzed the baseline characteristics, the effect of initial surgery and re-operation of eight NSTAPS (Netherlands SubThalamic and Pallidal Stimulation) patients and six previously published cases that underwent re-operation to a different target. RESULTS: In the NSTAPS cohort, two of the eight patients showed more than 30% improvement of off-drug motor symptoms after re-operation. The initial DBS leads of these patients were off target. In the cases from the literature, 30% off-drug motor improvement was seen in all three patients re-operated from GPi to STN and none of the three patients re-operated from STN to GPi. Only one of the three cases from the literature where any improvement was seen with the operation had a confirmed on target lead location after the first surgery, while the other two patients did not undergo post-operative imaging after the first surgery. CONCLUSIONS: Re-operation to a different target due to lack of effect appears to have a limited chance of leading to objective improvement if the leads were correctly placed during initial surgery.

Structural changes in cerebellar outflow tracts after thalamotomy in essential tremor.

BACKGROUND: This study set out to determine whether structural changes are present outside the thalamus after thalamotomy in patients with essential tremor (ET), specifically in the cerebellorubrothalamic tracts. We hypothesized that diffusion tensor imaging (DTI) would detect these changes. METHODS: We collected DTI scans and analyzed differences in Fractional Anisotropy (FA) and Mean Diffusivity (MD) between the left and right superior and middle cerebellar peduncle in ET patients that have undergone unilateral, left, thalamotomy and ET patients that did not undergo thalamotomy (control group). We used classical ROI-based statistics to determine whether changes are present. RESULTS: We found decreased FA and increased MD values in the right superior cerebellar peduncle leading to the left, lesioned thalamus, only in the thalamotomy group. CONCLUSIONS: Our study suggests long-term structural changes in the cerebellorubrothalamic tract after thalamotomy. This contributes to further understanding of the biological mechanism following surgical lesions in the basal ganglia.

Stereotactic neurosurgery for tremor.

The role of the motor thalamus as surgical target in stereotactic neurosurgery for different kinds of tremor is discussed. For tremor in Parkinson's disease, the subthalamic nucleus becomes more and more often the surgical target, because this target also gives relief of other and more incapacitating symptoms (hypokinesia, rigidity). Stimulation is as effective in tremor suppression as coagulation but has less adverse events and permits bilateral surgery. In selected cases, thalamotomy can still be indicated.