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

2021 ◽  
Author(s):  
Maarten Bot ◽  
Anne-Fleur van Rootselaari ◽  
Vincent Odekerken ◽  
Joke Dijk ◽  
Rob M A de Bie ◽  
...  

Abstract 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.

2020 ◽  
Vol 10 (12) ◽  
pp. 925
Author(s):  
Christian Iorio-Morin ◽  
Anton Fomenko ◽  
Suneil K. Kalia

Tremor is a prevalent symptom associated with multiple conditions, including essential tremor (ET), Parkinson’s disease (PD), multiple sclerosis (MS), stroke and trauma. The surgical management of tremor evolved from stereotactic lesions to deep-brain stimulation (DBS), which allowed safe and reversible interference with specific neural networks. This paper reviews the current literature on DBS for tremor, starting with a detailed discussion of current tremor targets (ventral intermediate nucleus of the thalamus (Vim), prelemniscal radiations (Raprl), caudal zona incerta (Zi), thalamus (Vo) and subthalamic nucleus (STN)) and continuing with a discussion of results obtained when performing DBS in the various aforementioned tremor syndromes. Future directions for DBS research are then briefly discussed.


Neurology ◽  
2020 ◽  
Vol 94 (10) ◽  
pp. e1073-e1084 ◽  
Author(s):  
Takashi Tsuboi ◽  
Zakia Jabarkheel ◽  
Pamela R. Zeilman ◽  
Matthew J. Barabas ◽  
Kelly D. Foote ◽  
...  

ObjectiveTo assess longitudinal tremor outcomes with ventral intermediate nucleus deep brain stimulation (VIM DBS) in patients with dystonic tremor (DT) and to compare with DBS outcomes in essential tremor (ET).MethodsWe retrospectively investigated VIM DBS outcomes for 163 patients followed at our center diagnosed with either DT or ET. The Fahn-Tolosa-Marin tremor rating scale (TRS) was used to assess change in tremor and activities of daily living (ADL) at 6 months, 1 year, 2–3 years, 4–5 years, and ≥6 years after surgery.ResultsTwenty-six patients with DT and 97 patients with ET were analyzed. Compared to preoperative baseline, there were significant improvements in TRS motor up to 4–5 years (52.2%; p = 0.032) but this did not reach statistical significance at ≥6 years (46.0%, p = 0.063) in DT, which was comparable to the outcomes in ET. While the improvements in the upper extremity tremor, head tremor, and axial tremor were also comparable between DT and ET throughout the follow-up, the ADL improvements in DT were lost at 2–3 years follow-up.ConclusionOverall, tremor control with VIM DBS in DT and ET was comparable and remained sustained at long term likely related to intervention at the final common node in the pathologic tremor network. However, the long-term ADL improvements in DT were not sustained, possibly due to inadequate control of concomitant dystonia symptoms. These findings from a large cohort of DT indicate that VIM targeting is reasonable if the tremor is considerably more disabling than the dystonic features.Classification of evidenceThis study provides Class IV evidence that VIM DBS improves tremor in patients with DT or ET.


2019 ◽  
Author(s):  
Shane Lee ◽  
Wael F Asaad ◽  
Stephanie R Jones

AbstractEssential tremor (ET) is the most common movement disorder, in which the primary symptom is a prominent, involuntary 4–10 Hz movement. For severe, medication refractory cases, deep brain stimulation (DBS) targeting the ventral intermediate nucleus of the thalamus (VIM) can be an effective treatment for cessation of tremor and is thought to work in part by disrupting tremor frequency oscillations (TFOs) in VIM. However, DBS is not universally effective and may be further disrupting cerebellar-mediated activity in the VIM. Here, we applied biophysically detailed computational modeling to investigate whether the efficacy of DBS is affected by the mechanism of generation of TFOs or by the pattern of stimulation. We simulated the effects of DBS using standard, asymmetric pulses as well as biphasic, symmetric pulses to understand biophysical mechanisms of how DBS disrupts TFOs generated either extrinsically or intrinsically. The model results suggested that the efficacy of DBS in the VIM is affected by the mechanism of generation of TFOs. Symmetric biphasic DBS reduced TFOs more than standard DBS in both networks, and these effects were stronger in the intrinsic network. For intrinsic tremor frequency activity, symmetric biphasic DBS was more effective at reducing TFOs. Simulated non-tremor signals were also transmitted during symmetric biphasic DBS, suggesting that this type of DBS may help to reduce side effects caused by disruption of the cerebellothalamocortical pathway. Biophysical details in the model provided a mechanistic interpretation of the cellular and network dynamics contributing to these effects that can be empirically tested in future studies.Significance StatementEssential tremor (ET) is a common movement disorder, whose primary symptom is an involuntary rhythmic movement of the limbs or head. An area of the human tha-lamus demonstrates electrical activity that oscillates at the frequencies of tremor, and deep brain stimulation (DBS) in this area can reduce tremor. It is not fully understood how DBS affects tremor frequency activity in the thalamus, and studying different patterns of DBS stimulation may help to clarify these mechanisms. We created a computational model of different shapes of DBS and studied how they reduce different hypothesized generators of tremor frequency activity. A greater understanding of how DBS affects the thalamus may lead to improved treatments to reduce tremor and alleviate side effects in patients with ET.


2020 ◽  
Vol 131 (1) ◽  
pp. 167-176 ◽  
Author(s):  
B.J. Wilkes ◽  
A. Wagle Shukla ◽  
A. Casamento-Moran ◽  
C.W. Hess ◽  
E.A. Christou ◽  
...  

2010 ◽  
Vol 112 (3) ◽  
pp. 491-496 ◽  
Author(s):  
Takashi Morishita ◽  
Kelly D. Foote ◽  
Samuel S. Wu ◽  
Charles E. Jacobson ◽  
Ramon L. Rodriguez ◽  
...  

Object Microelectrode recording (MER) and macrostimulation (test stimulation) are used to refine the optimal deep brain stimulation (DBS) lead placement within the operative setting. It is well known that there can be a microlesion effect with microelectrode trajectories and DBS insertion. The aim of this study was to determine the impact of intraoperative MER and lead placement on tremor severity in a cohort of patients with essential tremor. Methods Consecutive patients with essential tremor undergoing unilateral DBS (ventral intermediate nucleus stimulation) for medication-refractory tremor were evaluated. Tremor severity was measured at 5 time points utilizing a modified Tremor Rating Scale: 1) immediately before MER; 2) immediately after MER; 3) immediately after lead implantation; 4) 6 months after DBS implantation in the off-DBS condition; and 5) 6 months after implantation in the on-DBS condition. To investigate the impact of the MER and DBS lead placement, Wilcoxon signed-rank tests were applied to test changes in tremor severity scores over the surgical course. In addition, a generalized linear mixed model including factors that potentially influenced the impact of the microlesion was also used for analysis. Results Nineteen patients were evaluated. Improvement was noted in the total modified Tremor Rating Scale, postural, and action tremor scores (p < 0.05) as a result of MER and DBS lead placement. The improvements observed following lead placement were similar in magnitude to what was observed in the chronically programmed clinic setting parameters at 6 months after lead implantation. Improvement in tremor severity was maintained over time even in the off-DBS condition at 6 months, which was supportive of a prolonged microlesion effect. The number of macrostimulation passes, the number of MER passes, and disease duration were not related to the change in tremor severity score over time. Conclusions Immediate improvement in postural and intention tremors may result from MER and DBS lead placement in patients undergoing DBS for essential tremor. This improvement could be a predictor of successful DBS lead placement at 6 months. Clinicians rating patients in the operating room should be aware of these effects and should consider using rating scales before and after lead placement to take these effects into account when evaluating outcome in and out of the operating room.


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