scholarly journals Selecting the most effective DBS contact in essential tremor patients based on individual tractography

2020 ◽  
Author(s):  
Jan Niklas Petry-Schmelzer ◽  
Till A. Dembek ◽  
Julia K. Steffen ◽  
Hannah Jergas ◽  
Haidar S. Dafsari ◽  
...  
Keyword(s):  
Essential Tremor ◽  
Clinical Effect ◽  
Diffusion Tensor ◽  
Clinical Effectiveness ◽  
Clinical Testing ◽  
Group Level ◽  
Linear Mixed Effects ◽  
Test Stimulation ◽  
The Individual ◽  
Deep Brain

AbstractPostoperative choice of the most effective DBS contact in patients with essential tremor (ET) so far relies on lengthy clinical testing. It has been shown that the postoperative effectiveness of DBS contacts depends on the distance to the dentatorubrothalamic tract (DRTT). Here, we investigated whether the most effective DBS contact could be determined from the stimulation overlap with the individual DRTT. Seven ET patients with bilateral thalamic deep brain stimulation were included retrospectively. Tremor control was assessed contact-wise during test stimulation with 2mA. The individual DRTTs were identified from diffusion tensor imaging. Contacts were ranked by their overlap of the test stimulation with the respective DRTT in relation to their clinical effectiveness. A linear mixed-effects model was calculated to determine the influence of the DRTT-overlap on tremor control. In 92.9 % of the cases, the contact with the best clinical effect was the contact with the highest or second-highest DRTT-overlap. On the group level, the DRTT-overlap explained 26.7% of the variance of the clinical outcome (p<0.001). To conclude, data suggest that the overlap with the DRTT based on individual tractography may serve as a marker to determine the most effective DBS contact in ET patients and reduce burdensome clinical testing in the future.

scholarly journals Selecting the Most Effective DBS Contact in Essential Tremor Patients Based on Individual Tractography

2020 ◽  
Vol 10 (12) ◽  
pp. 1015
Author(s):  
Jan Niklas Petry-Schmelzer ◽  
Till A. Dembek ◽  
Julia K. Steffen ◽  
Hannah Jergas ◽  
Haidar S. Dafsari ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Diffusion Tensor ◽  
Clinical Effectiveness ◽  
Clinical Testing ◽  
Linear Mixed Effects ◽  
Test Stimulation ◽  
The Individual ◽  
Deep Brain

Postoperative choice of the most effective deep brain stimulation (DBS) contact in patients with essential tremor (ET) so far relies on lengthy clinical testing. Previous studies showed that the postoperative effectiveness of DBS contacts depends on the distance to the dentatorubrothalamic tract (DRTT). Here, we investigated whether the most effective DBS contact could be determined from calculating stimulation overlap with the individual DRTT. Seven ET patients with bilateral thalamic deep brain stimulation were included retrospectively. Tremor control was assessed for each contact during test stimulation with 2mA. Individual DRTTs were identified from diffusion tensor imaging and contacts were ranked by their stimulation overlap with the respective DRTT in relation to their clinical effectiveness. A linear mixed-effects model was calculated to determine the influence of the DRTT overlap on tremor control. In 92.9% of investigated DBS leads, the contact with the best clinical effect was the contact with the highest or second-highest DRTT-overlap. At the group level, the DRTT-overlap explained 26.7% of the variance in the clinical outcomes (p < 0.001). Our data suggest that the overlap with the DRTT based on individual tractography may serve as a marker to determine the most effective DBS contact in ET patients and reduce burdensome clinical testing in the future.

scholarly journals Targeting the posterior subthalamic area for essential tremor: proposal for MRI-based anatomical landmarks

2019 ◽  
Vol 131 (3) ◽  
pp. 820-827 ◽  
Author(s):  
Andreas Nowacki ◽  
Ines Debove ◽  
Frédéric Rossi ◽  
Janine Ai Schlaeppi ◽  
Katrin Petermann ◽  
...  
Keyword(s):  
Essential Tremor ◽  
Rating Scale ◽  
Diffusion Tensor ◽  
Red Nucleus ◽  
Target Position ◽  
Postoperative Outcome ◽  
Clinical Effectiveness ◽  
Zona Incerta ◽  
Target Point ◽  
Anatomical Landmarks

OBJECTIVEDeep brain stimulation (DBS) of the posterior subthalamic area (PSA) is an alternative to thalamic DBS for the treatment of essential tremor (ET). The dentato-rubro-thalamic tract (DRTT) has recently been proposed as the anatomical substrate underlying effective stimulation. For clinical purposes, depiction of the DRTT mainly depends on diffusion tensor imaging (DTI)–based tractography, which has some drawbacks. The objective of this study was to present an accurate targeting strategy for DBS of the PSA based on anatomical landmarks visible on MRI and to evaluate clinical effectiveness.METHODSThe authors performed a retrospective cohort study of a prospective series of 11 ET patients undergoing bilateral DBS of the PSA. The subthalamic nucleus and red nucleus served as anatomical landmarks to define the target point within the adjacent PSA on 3-T T2-weighted MRI. Stimulating contact (SC) positions with reference to the midcommissural point were analyzed and projected onto the stereotactic atlas of Morel. Postoperative outcome assessment after 6 and 12 months was based on change in Tremor Rating Scale (TRS) scores.RESULTSActual target position corresponded to the intended target based on anatomical landmarks depicted on MRI. The total TRS score was reduced (improved) from 47.2 ± 15.7 to 21.3 ± 10.7 (p < 0.001). No severe complication occurred. The mean SC position projected onto the PSA at the margin of the cerebellothalamic fascicle and the zona incerta.CONCLUSIONSTargeting of the PSA based on anatomical landmarks representable on MRI is reliable and leads to accurate lead placement as well as good long-term clinical outcome.

scholarly journals “Asleep” deep brain stimulation for essential tremor

2016 ◽  
Vol 124 (6) ◽  
pp. 1842-1849 ◽  
Author(s):  
Tsinsue Chen ◽  
Zaman Mirzadeh ◽  
Kristina Chapple ◽  
Margaret Lambert ◽  
Rohit Dhall ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Activities Of Daily Living ◽  
General Anesthesia ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Daily Living ◽  
Perioperative Complications ◽  
Test Stimulation ◽  
Intraoperative Test ◽  
Deep Brain

OBJECT Deep brain stimulation (DBS) performed under general anesthesia (“asleep” DBS) has not been previously reported for essential tremor. This is in part due to the inability to visualize the target (the ventral intermediate nucleus [VIM]) on MRI. The authors evaluate the efficacy of this asleep technique in treating essential tremor by indirect VIM targeting. METHODS The authors retrospectively reviewed consecutive cases of initial DBS for essential tremor performed by a single surgeon. DBS was performed with patients awake (n = 40, intraoperative test stimulation without microelectrode recording) or asleep (n = 17, under general anesthesia). Targeting proceeded with standardized anatomical coordinates on preoperative MRI. Intraoperative CT was used for stereotactic registration and lead position confirmation. Functional outcomes were evaluated with pre- and postoperative Bain and Findley Tremor Activities of Daily Living scores. RESULTS A total of 29 leads were placed in asleep patients, and 60 were placed in awake patients. Bain and Findley Tremor Activities of Daily Living Questionnaire scores were not significantly different preoperatively for awake versus asleep cohorts (p = 0.2). The percentage of postoperative improvement was not significantly different between asleep (48.6%) and awake (45.5%) cohorts (p = 0.35). Euclidean error (mm) was higher for awake versus asleep patients (1.7 ± 0.8 vs 1.2 ± 0.4, p = 0.01), and radial error (mm) trended higherfor awake versus asleep patients (1.3 ± 0.8 vs 0.9 ± 0.5, p = 0.06). There were no perioperative complications. CONCLUSIONS In the authors’ initial experience, asleep VIM DBS for essential tremor without intraoperative test stimulation can be performed safely and effectively.

scholarly journals Intraoperative test stimulation versus stereotactic accuracy as a surgical end point: a comparison of essential tremor outcomes after ventral intermediate nucleus deep brain stimulation

2018 ◽  
Vol 129 (2) ◽  
pp. 290-298 ◽  
Author(s):  
Tsinsue Chen ◽  
Zaman Mirzadeh ◽  
Kristina M. Chapple ◽  
Margaret Lambert ◽  
Virgilio G. H. Evidente ◽  
...  
Keyword(s):  
Quality Of Life ◽  
Deep Brain Stimulation ◽  
Essential Tremor ◽  
Conscious Sedation ◽  
Test Stimulation ◽  
Ventral Intermediate Nucleus ◽  
The Mean ◽  
Intraoperative Test ◽  
Deep Brain

OBJECTIVEVentral intermediate nucleus deep brain stimulation (DBS) for essential tremor is traditionally performed with intraoperative test stimulation and conscious sedation, without general anesthesia (GA). Recently, the authors reported retrospective data on 17 patients undergoing DBS after induction of GA with standardized anatomical coordinates on T1-weighted MRI sequences used for indirect targeting. Here, they compare prospectively collected data from essential tremor patients undergoing DBS both with GA and without GA (non-GA).METHODSClinical outcomes were prospectively collected at baseline and 3-month follow-up for patients undergoing DBS surgery performed by a single surgeon. Stereotactic, euclidean, and radial errors of lead placement were calculated. Functional (activities of daily living), quality of life (Quality of Life in Essential Tremor [QUEST] questionnaire), and tremor severity outcomes were compared between groups.RESULTSFifty-six patients underwent surgery: 16 without GA (24 electrodes) and 40 with GA (66 electrodes). The mean baseline functional scores and QUEST summary indices were not different between groups (p = 0.91 and p = 0.59, respectively). Non-GA and GA groups did not differ significantly regarding mean postoperative percentages of functional improvement (non-GA, 47.9% vs GA, 48.1%; p = 0.96) or QUEST summary indices (non-GA, 79.9% vs GA, 74.8%; p = 0.50). Accuracy was comparable between groups (mean radial error 0.9 ± 0.3 mm for non-GA and 0.9 ± 0.4 mm for GA patients) (p = 0.75). The mean euclidean error was also similar between groups (non-GA, 1.1 ± 0.6 mm vs GA, 1.2 ± 0.5 mm; p = 0.92). No patient had an intraoperative complication, and the number of postoperative complications was not different between groups (non-GA, n = 1 vs GA, n = 10; p = 0.16).CONCLUSIONSDBS performed with the patient under GA to treat essential tremor is as safe and effective as traditional DBS surgery with intraoperative test stimulation while the patient is under conscious sedation without GA.

Concepts and Methods in Chronic Thalamic Stimulation for Treatment of Tremor: Technique and Application

Neurosurgery ◽  
2001 ◽  
Vol 48 (3) ◽  
pp. 535-543 ◽  
Author(s):  
Joachim K. Krauss ◽  
Richard K. Simpson ◽  
William G. Ondo ◽  
Thomas Pohle ◽  
Jean-Marc Burgunder ◽  
...  
Keyword(s):  
Parkinson’S Disease ◽  
Parkinson's Disease ◽  
Deep Brain Stimulation ◽  
Side Effects ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Surgical Techniques ◽  
Symptomatic Improvement ◽  
Test Stimulation ◽  
Deep Brain

Abstract OBJECTIVE To rationalize the technique and reduce the costs associated with chronic deep brain stimulation of the thalamus for treatment of refractory tremor. METHODS The efficacy and safety of a modification in surgical techniques was prospectively assessed in 94 patients with tremor. Bilateral electrodes were implanted in 29 patients, and 65 patients received unilateral implants. Forty-five patients had Parkinson's disease tremor, 42 patients had essential tremor, and 7 patients had kinetic tremors of different causes. In all instances, intraoperative stimulations to analyze the thresholds of intrinsic and extrinsic responses were performed directly with the implanted leads. The electrodes were repositioned until satisfactory results were achieved. The pulse generators were implanted directly after the first step in the same operative session. Patients were not subjected to interoperative test stimulation trials. RESULTS Postoperative improvement of tremor at a mean follow-up of 11.9 months was rated as excellent in 47 patients (50%), marked in 37 patients (39%), moderate in 8 patients (9%), and minor in 2 patients (2%). There was no persistent morbidity related to surgery. In patients with Parkinson's disease, the symptomatic improvement of tremor was rated as excellent in 51% of patients, marked in 36%, moderate in 11%, and minor in 2%. In patients with essential tremor, symptomatic outcome was classified as excellent in 57% of patients, marked in 36%, moderate in 5%, and minor in 2%. Six of the seven patients with kinetic tremor achieved marked symptomatic improvement, and one patient experienced moderate improvement. Forty patients experienced stimulation-related side effects. Side effects were mild in general, and they were reversible with a change in electrical parameters. They occurred more frequently in patients who had bilateral stimulation. CONCLUSION Excellent to marked improvement of tremor is achieved in the majority of patients with physiological target determination via implanted leads in thalamic deep brain stimulation. Interoperative test stimulation trials are unnecessary. Modifications in technique may help to reduce the costs of the related hospital stay.

scholarly journals Use of quantitative tremor evaluation to enhance target selection during deep brain stimulation surgery for essential tremor

2015 ◽  
Vol 1 (1) ◽  
pp. 488-492 ◽  
Author(s):  
A. Shah ◽  
J. Coste ◽  
JJ. Lemaire ◽  
E. Schkommodau ◽  
S. Hemm-Ode
Keyword(s):  
Deep Brain Stimulation ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Quantitative Methods ◽  
Evaluation Method ◽  
Target Selection ◽  
Thalamic Nuclei ◽  
Visual Evaluation ◽  
Test Stimulation ◽  
Deep Brain

AbstractDeep brain stimulation (DBS), an effective surgical treatment for Essential Tremor (ET), requires test stimulations in the thalamus to find the optimum site for permanent electrode implantation. During these test stimulations, the changes in tremor are only visually evaluated. This, along with other parameters, increases the subjectivity when comparing the efficacy of different thalamic nuclei. We developed a method to quantitatively evaluate tremor during the test stimulations of DBS surgery and applied to 6 ET patients undergoing this treatment. From the quantitative data collected, we identified effective stimulation amplitudes for every test stimulation position and compared it with the ones identified visually during the surgery. We also classified the data based on the thalamic nuclei in which the center of the stimulating contact was present during test stimulations. Results indicate that, to achieve the same reduction in tremor, on average, the stimulation amplitude identified by our method was 0.6 mA lower than those identified by visual evaluation. The comparison of the different thalamic nuclei showed that stimulations in the Ventro-oral and the Intermediolateral nuclei of the thalamus result in higher reduction in tremor for similar stimulation amplitudes as the frequently targeted Ventrointermediate nucleus. We conclude that our quantitative tremor evaluation method is more sensitive than the widely used visual evaluation. Using such quantitative methods will aid in identifying the optimum target structure for patients undergoing DBS.

QUALITY OF INDIVIDUAL AND GROUP LEVEL INTERVENTIONS FOR FIRST EPISODE PSYCHOSIS AT THE TERTIARY PSYCHIATRIC HOSPITAL IN UGANDA.

2020 ◽  
Author(s):  
Emmanuel Kiiza Mwesiga ◽  
Noeline Nakasujja ◽  
Lawrence Nankaba ◽  
Juliet Nakku ◽  
Seggane Musisi
Keyword(s):  
Psychiatric Hospital ◽  
Psychotic Disorders ◽  
First Episode Psychosis ◽  
First Episode ◽  
Group Level ◽  
Group Interventions ◽  
Episode Psychosis ◽  
Essential Components ◽  
The Individual

Introduction: Individual and group level interventions have the largest effect on outcomes in patients with the first episode of psychosis. The quality of these individual and group level interventions provided to first-episode psychosis patients in Uganda is unclear.Methods: The study was performed at Butabika National Psychiatric Teaching and referral hospital in Uganda. A retrospective chart review of recently discharged adult in-patients with the first episode of psychosis was first performed to determine the proportion of participants who received the different essential components for individual and group level interventions. From the different proportions, the quality of the services across the individual and group interventions was determined using the first-Episode Psychosis Services Fidelity Scale (FEPS-FS). The FEPS-FS assigns a grade of 1-5 on a Likert scale depending on the proportion of patients received the different components of the intervention. Results: The final sample included 156 first-episode psychosis patients. The median age was 27 years [IOR (24-36)] with 55% of participants of the female gender. 13 essential components across the individual and group interventions were assessed and their quality quantified. All 13 essential components had poor quality with the range of scores on the FEPS-FS of 1-3. Only one essential component assessed (use of single antipsychotics) had moderate quality.Discussion: Among current services at the National psychiatric hospital of Uganda, the essential for individual and group level interventions for psychotic disorders are of low quality. Further studies are required on how the quality of these interventions can be improved.

Reply to Connor and Evers (2020): Critique of the Bias of Crowds Model Simply Restates the Model

2020 ◽  
Author(s):  
Keith Payne ◽  
Heidi A. Vuletich ◽  
Kristjen B. Lundberg
Keyword(s):  
Implicit Bias ◽  
Group Level ◽  
Systemic Racism ◽  
Individual Level ◽  
The Core ◽  
Psychological Science ◽  
Implicit Biases ◽  
The Individual

The Bias of Crowds model (Payne, Vuletich, &amp; Lundberg, 2017) argues that implicit bias varies across individuals and across contexts. It is unreliable and weakly associated with behavior at the individual level. But when aggregated to measure context-level effects, the scores become stable and predictive of group-level outcomes. We concluded that the statistical benefits of aggregation are so powerful that researchers should reconceptualize implicit bias as a feature of contexts, and ask new questions about how implicit biases relate to systemic racism. Connor and Evers (2020) critiqued the model, but their critique simply restates the core claims of the model. They agreed that implicit bias varies across individuals and across contexts; that it is unreliable and weakly associated with behavior at the individual level; and that aggregating scores to measure context-level effects makes them more stable and predictive of group-level outcomes. Connor and Evers concluded that implicit bias should be considered to really be noisily measured individual construct because the effects of aggregation are merely statistical. We respond to their specific arguments and then discuss what it means to really be a feature of persons versus situations, and multilevel measurement and theory in psychological science more broadly.

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