Coordinates Of Active Contacts Research Articles

Individualized Anatomy-Based Targeting for VIM-cZI DBS in Essential Tremor

Deep brain stimulation of the ventral intermediate nucleus (VIM) or caudal zona incerta (cZI) is effective for refractory essential tremor (ET). To refine stereotactic planning for lead placement, we developed a unique individualized anatomy-based planning protocol that targets both the VIM and the cZI in patients with ET. 33 patients with ET underwent VIM-cZI lead implantation with targeting based on our protocol. Indirect targeting was adjusted based on anatomic landmarks as reference lines bisecting the red nuclei and ipsilateral subthalamus. Outcomes were evaluated through the follow-up of 31.1 ± 18.4 months. Active contact coordinates were obtained from reconstructed electrodes in the Montreal Neurological Institute space using the MATLAB Lead-DBS toolbox. Mean tremor improvement was 79.7% ±22.4% and remained stable throughout the follow-up period. Active contacts at last postoperative visit had mean Montreal Neurological Institute coordinates of 15.5 ± 1.6 mm lateral to the intercommissural line, 15.3± 1.8 mm posterior to the anterior commissure, and 1.4 ± 2.9 mm below the intercommissural plane. No hemorrhagic complications were observed in the analyzed group. Individualized anatomy-based VIM-cZI targeting is feasible and safe and is associated with favorable tremor outcomes.

Sevoflurane and Parkinson’s Disease

General anesthetics-induced changes of electrical oscillations in the basal ganglia may render the identification of the stimulation targets difficult. The authors hypothesized that while sevoflurane anesthesia entrains coherent lower frequency oscillations, it does not affect the identification of the subthalamic nucleus and clinical outcome. A cohort of 19 patients with Parkinson's disease with comparable disability underwent placement of electrodes under either sevoflurane general anesthesia (n = 10) or local anesthesia (n = 9). Microelectrode recordings during targeting were compared for neuronal spiking characteristics and oscillatory dynamics. Clinical outcomes were compared at 5-yr follow-up. Under sevoflurane anesthesia, subbeta frequency oscillations predominated (general vs. local anesthesia, mean ± SD; delta: 13 ± 7.3% vs. 7.8 ± 4.8%; theta: 8.4 ± 4.1% vs. 3.9 ± 1.6%; alpha: 8.1 ± 4.1% vs. 4.8 ± 1.5%; all P < 0.001). In addition, distinct dorsolateral beta and ventromedial gamma oscillations were detected in the subthalamic nucleus solely in awake surgery (mean ± SD; dorsal vs. ventral beta band power: 20.5 ± 6.6% vs. 15.4 ± 4.3%; P < 0.001). Firing properties of subthalamic neurons did not show significant difference between groups. Clinical outcomes with regard to improvement in motor and psychiatric symptoms and adverse effects were comparable for both groups. Tract numbers of microelectrode recording, active contact coordinates, and stimulation parameters were also equivalent. Sevoflurane general anesthesia decreased beta-frequency oscillations by inducing coherent lower frequency oscillations, comparable to the pattern seen in the scalp electroencephalogram. Nevertheless, sevoflurane-induced changes in electrical activity patterns did not reduce electrode placement accuracy and clinical effect. These observations suggest that microelectrode-guided deep brain stimulation under sevoflurane anesthesia is a feasible clinical option.

Electrode Location in a Microelectrode Recording-Based Model of the Subthalamic Nucleus Can Predict Motor Improvement After Deep Brain Stimulation for Parkinson's Disease.

Motor improvement after deep brain stimulation (DBS) in the subthalamic nucleus (STN) may vary substantially between Parkinson’s disease (PD) patients. Research into the relation between improvement and active contact location requires a correction for anatomical variation. We studied the relation between active contact location relative to the neurophysiological STN, estimated by the intraoperative microelectrode recordings (MER-based STN), and contralateral motor improvement after one year. A generic STN shape was transformed to fit onto the stereotactically defined MER sites. The location of 43 electrodes (26 patients), derived from MRI-fused CT images, was expressed relative to this patient-specific MER-based STN. Using regression analyses, the relation between contact location and motor improvement was studied. The regression model that predicts motor improvement based on levodopa effect alone was significantly improved by adding the one-year active contact coordinates (R2 change = 0.176, p = 0.014). In the combined prediction model (adjusted R2 = 0.389, p < 0.001), the largest contribution was made by the mediolateral location of the active contact (standardized beta = 0.490, p = 0.002). With the MER-based STN as a reference, we were able to find a significant relation between active contact location and motor improvement. MER-based STN modeling can be used to complement imaging-based STN models in the application of DBS.

Non-motor outcomes of subthalamic stimulation in Parkinson's disease depend on location of active contacts

BackgroundSubthalamic nucleus (STN) deep brain stimulation (DBS) improves quality of life (QoL), motor, and non-motor symptoms (NMS) in Parkinson's disease (PD). Few studies have investigated the influence of the location of neurostimulation on NMS. ObjectiveTo investigate the impact of active contact location on NMS in STN-DBS in PD. MethodsIn this prospective, open-label, multicenter study including 50 PD patients undergoing bilateral STN-DBS, we collected NMSScale (NMSS), NMSQuestionnaire (NMSQ), Hospital Anxiety and Depression Scale (anxiety/depression, HADS-A/-D), PDQuestionnaire-8 (PDQ-8), Scales for Outcomes in PD-motor examination, motor complications, activities of daily living (ADL), and levodopa equivalent daily dose (LEDD) preoperatively and at 6 months follow-up. Changes were analyzed with Wilcoxon signed-rank/t-test and Bonferroni-correction for multiple comparisons. Although the STN was targeted visually, we employed an atlas-based approach to explore the relationship between active contact locations and DBS outcomes. Based on fused MRI/CT-images, we identified Cartesian coordinates of active contacts with patient-specific Mai-atlas standardization. We computed linear mixed-effects models with x-/y-/z-coordinates as independent, hemispheres as within-subject, and test change scores as dependent variables. ResultsNMSS, NMSQ, PDQ-8, motor examination, complications, and LEDD significantly improved at follow-up. Linear mixed-effect models showed that NMS and QoL improvement significantly depended on more medial (HADS-D, NMSS), anterior (HADS-D, NMSQ, PDQ-8), and ventral (HADS-A/-D, NMSS, PDQ-8) neurostimulation. ADL improved more in posterior, LEDD in lateral neurostimulation locations. No relationship was observed for motor examination and complications scores. ConclusionsOur study provides evidence that more anterior, medial, and ventral STN-DBS is significantly related to more beneficial non-motor outcomes.

Deep Brain Stimulation in Patients with Parkinson's Disease: Effect on Psychiatric Symptoms and Quality of Life.

To determine the effect on psychiatric symptoms and quality of life in 30 patients with Parkinson's disease (PD) treated with deep brain stimulation (DBS) of both subthalamic nuclei (STN) after 1 year of follow-up. We conducted a prospective 1-year follow-up study with a baseline assessment before and 6 and 12 months after surgery. The following were used as assessment instruments: the Bech-Rafaelsen Melancholia Scale (MES), the Bech-Rafaelsen Mania Scale (MAS), the Beck Scale for Suicidal Ideation (SSI), the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS), the Oviedo Sleep Questionnaire (OSQ), the 36-Item Short Form Health Survey (SF-36), the Unified Parkinson's Disease Rating Scale (UPDRS), the dose of levodopa, and the active contact stereotactic coordinates. We recorded a clinical improvement between baseline with medication use (ON medication) and the results obtained at 6 and 12 months with medication use and stimulation (ON stimulation, ON medication) in MES and OSQ (p < 0.0001) and in SF-36 (p < 0.005). No changes were observed in MAS and SSI. There was a clinical improvement between baseline with ON medication and the results obtained at 12 months with ON stimulation, ON medication in Y-BOCS (p < 0.04). Also, there was a 53.3% reduction in levodopa at 6 months and a 54.7% reduction at 12 months after surgery (p < 0.0001). There was an improvement between baseline with OFF medication and the results obtained at 6 and 12 months OFF medication, ON stimulation (p < 0.0001) in UPDRS-III. There were no statistically significant differences between the initial and final active contact coordinates, or between stimulation parameters. DBS of the STN in patients with PD is associated with an improvement in psychiatric (affective and sleep-wake cycle) symptoms, clinical motor symptoms, and quality of life at 1 year after surgery.

Fully automated targeting using nonrigid image registration matches accuracy and exceeds precision of best manual approaches to subthalamic deep brain stimulation targeting in Parkinson disease.

Finding the optimal location for the implantation of the electrode in deep brain stimulation (DBS) surgery is crucial for maximizing the therapeutic benefit to the patient. Such targeting is challenging for several reasons, including anatomic variability between patients as well as the lack of consensus about the location of the optimal target. To compare the performance of popular manual targeting methods against a fully automatic nonrigid image registration-based approach. In 71 Parkinson disease subthalamic nucleus (STN)-DBS implantations, an experienced functional neurosurgeon selected the target manually using 3 different approaches: indirect targeting using standard stereotactic coordinates, direct targeting based on the patient magnetic resonance imaging, and indirect targeting relative to the red nucleus. Targets were also automatically predicted by using a leave-one-out approach to populate the CranialVault atlas with the use of nonrigid image registration. The different targeting methods were compared against the location of the final active contact, determined through iterative clinical programming in each individual patient. Targeting by using standard stereotactic coordinates corresponding to the center of the motor territory of the STN had the largest targeting error (3.69 mm), followed by direct targeting (3.44 mm), average stereotactic coordinates of active contacts from this study (3.02 mm), red nucleus-based targeting (2.75 mm), and nonrigid image registration-based automatic predictions using the CranialVault atlas (2.70 mm). The CranialVault atlas method had statistically smaller variance than all manual approaches. Fully automatic targeting based on nonrigid image registration with the use of the CranialVault atlas is as accurate and more precise than popular manual methods for STN-DBS.

The effects of bilateral stimulation of the subthalamic nucleus on heart rate variability in patients with Parkinson’s disease

The beneficial effects of subthalamic nucleus deep brain stimulation (STN-DBS) on motor symptoms and quality of life in Parkinson's disease (PD) are well known, but little is known of the effects on autonomic function. Diffusion of current during stimulation of the STN may simultaneously involve the motor and nonmotor, limbic and associative areas of the STN. The aims of this study were to examine whether STN stimulation affects functions of the autonomic nervous system and, if so, to correlate the effects with the active contacts of electrodes in the STN. Eight PD patients with good motor control and quality of sleep after STN-DBS surgery were recruited. All patients had two days of recordings with portable polysomnography (PSG) (first night with stimulation "on" and second night "off"). From the PSG data, the first sleep cycle of each recording night was defined. Heart rate variability (HRV) was analyzed between the same uninterrupted periods of the two sleep nights. In addition, the optimal electrode positions were defined from postoperative MRI studies, and the coordinates of active contacts were confirmed. HRV spectral analysis showed that only low-frequency (LF)/high-frequency (HF) power was significantly activated in the stimulation "on" groups (P = 0.011). There was a significant negative correlation between power change of LF/HF and electrode position lateral to the midcommissural point (ρ = 0.857, P = 0.007) These results demonstrate that STN-DBS can enhance sympathetic regulation; the autonomic response may be due to electrical signals being distributed to limbic components of the STN or descending sympathetic pathways in the zona incerta.

How to Assess Active Contact Coordinates in Deep Brain Stimulation Surgery? Comparison of Three Methods for Determining the Position of the Active Contact

To date there is still no agreement in the literature on postoperative active contact coordinate (ACc) acquisition. The aim of the study is to test if the use of three methods commonly adopted in the literature for ACc acquisition (stereotactic X-rays (RXc), postoperative MRI (MRIc) and calculation of the expected ACc) for the same active contact (ACo) lead to significant differences. In our series of 176 ACo, mean euclidean distances were 1.2 ± 0.3, 2.1 ± 1.3, and 2.5 ± 1.6 mm between MRIc and RXc, RXc and EXc, and MRIc and EXc, respectively. Statistically significant differences along the three axes were found. Our results indicate that final ACc depends on the method adopted to acquire them. MRI and X-rays lead to a similar ACc acquisition. The difference between the EXc and the direct visualization methods (X-rays and MRI) is significantly higher.

NEUROPSYCHOLOGICAL EFFECTS AFTER CHRONIC SUBTHALAMIC STIMULATION AND THE TOPOGRAPHY OF THE NUCLEUS IN PARKINSON'S DISEASE

The neuropsychological effects of chronic subthalamic nucleus (STN)-deep brain stimulation (DBS) as a treatment for Parkinson's disease are variable. Whether these side effects result from the target per se or current diffusion into neighboring structures is uncertain. In this study, the relationship between clinical outcomes and coordinates of active contact are analyzed and compared between patients with and without neuropsychological sequelae. Thirty-eight Parkinsonian patients who underwent bilateral STN-DBS were enrolled in this retrospective cohort study. They were followed for at least 12 months. During the follow-up period, they were divided into two groups for comparison; Group A included patients with neuropsychological side effects and Group B was composed of patients without neuropsychological side effects. The position of the active contact of the electrode was defined with postoperative magnetic resonance imaging scans according to the midcommissural line. Active contact coordinates and clinical outcomes were compared for the two groups. Among the 38 Parkinsonian patients who underwent STN-DBS, eight patients who had neuropsychological side effects were assigned to Group A; the other 30 patients were assigned to Group B. In Groups A and B, the mean follow-up periods were 13.9 and 12.1 months, respectively, the Unified Parkinson's Disease Rating Scale motor score was improved by 53.4 and 45.2% (P = 0.24), respectively, and the levodopa equivalent daily dosage was decreased by 68.4 and 46.4% (P = 0.16), respectively. The mean coordinates of active contact in both Groups A and B were x = 10.1 and 10.5 mm, respectively, y = -2.8 and -3.9 mm, respectively, and z = -6.3 and -6.2 mm, respectively, relative to the midcommissural point. A significant difference was observed on the y axis (P = 0.01). When taking spatial influence into consideration, the neuropsychological effects of chronic STN-DBS were related to a significant anteriorly located active contact within the ventral STN in this preliminary study. This might suggest the existence of topography of STN in patients with Parkinson's disease concerning limbic and associative circuits.