Outcome Of Deep Brain Stimulation Research Articles

Postmortem Dissections of Common Targets for Lesion and Deep Brain Stimulation Surgeries.

The subthalamic nucleus (STN), globus pallidus internus (GPi), and pedunculopontine nucleus (PPN) are effective targets for deep brain stimulation (DBS) in many pathological conditions. Previous literature has focused on appropriate stimulation targets and their relationships with functional neuroanatomic pathways; however, comprehensive anatomic dissections illustrating these nuclei and their connections are lacking. This information will provide insight into the anatomic basis of stimulation-induced DBS benefits and side effects. To combine advanced cadaveric dissection techniques and ultrahigh field magnetic resonance imaging (MRI) to explore the anatomy of the STN, GPi, and PPN with their associated fiber pathways. A total of 10 cadaveric human brains and 2 hemispheres of a cadaveric head were examined using fiber dissection techniques. The anatomic dissections were compared with 11.1 Tesla (T) structural MRI and 4.7 T MRI fiber tractography. The extensive connections of the STN (caudate nucleus, putamen, medial frontal cortex, substantia innominata, substantia nigra, PPN, globus pallidus externus (GPe), GPi, olfactory tubercle, hypothalamus, and mammillary body) were demonstrated. The connections of GPi to the thalamus, substantia nigra, STN, amygdala, putamen, PPN, and GPe were also illustrated. The PPN was shown to connect to the STN and GPi anteriorly, to the cerebellum inferiorly, and to the substantia nigra anteriorly and superiorly. This study demonstrates connections using combined anatomic microdissections, ultrahigh field MRI, and MRI tractography. The anatomic findings are analyzed in relation to various stimulation-induced clinical effects. Precise knowledge of neuroanatomy, anatomic relationships, and fiber connections of the STN, GPi, PPN will likely enable more effective targeting and improved DBS outcomes.

Electrophysiology and Structural Connectivity of the Posterior Hypothalamic Region: Much to Learn From a Rare Indication of Deep Brain Stimulation.

Cluster headache (CH) is among the most common and debilitating autonomic cephalalgias. We characterize clinical outcomes of deep brain stimulation (DBS) to the posterior hypothalamic region through a novel analysis of the electrophysiological topography and tractography-based structural connectivity. The left posterior hypothalamus was targeted ipsilateral to the refractory CH symptoms. Intraoperatively, field potentials were captured in 1 mm depth increments. Whole-brain probabilistic tractography was conducted to assess the structural connectivity of the estimated volume of activated tissue (VAT) associated with therapeutic response. Stimulation of the posterior hypothalamic region led to the resolution of CH symptoms, and this benefit has persisted for 1.5-years post-surgically. Active contacts were within the posterior hypothalamus and dorsoposterior border of the ventral anterior thalamus (VAp). Delta- (3 Hz) and alpha-band (8 Hz) powers increased and peaked with proximity to the posterior hypothalamus. In the posterior hypothalamus, the delta-band phase was coupled to beta-band amplitude, the latter of which has been shown to increase during CH attacks. Finally, we identified that the VAT encompassing these regions had a high proportion of streamlines of pain processing regions, including the insula, anterior cingulate gyrus, inferior parietal lobe, precentral gyrus, and the brainstem. Our unique case study of posterior hypothalamic region DBS supports durable efficacy and provides a platform using electrophysiological topography and structural connectivity, to improve mechanistic understanding of CH and this promising therapy.

Defining the optimal target for anterior thalamic deep brain stimulation in patients with drug-refractory epilepsy.

The anterior thalamic nucleus (ATN) is a common target for deep brain stimulation (DBS) for the treatment of drug-refractory epilepsy. However, no atlas-based optimal DBS (active contacts) target within the ATN has been definitively identified. The object of this retrospective study was to analyze the relationship between the active contact location and seizure reduction to establish an atlas-based optimal target for ATN DBS. From among 25 patients who had undergone ATN DBS surgery for drug-resistant epilepsy between 2016 and 2018, those who had follow-up evaluations for more than 1 year were eligible for study inclusion. After an initial stimulation period of 6 months, patients were classified as responsive (≥ 50% median decrease in seizure frequency) or nonresponsive (< 50% median decrease in seizure frequency) to treatment. Stimulation parameters and/or active contact positions were adjusted in nonresponsive patients, and their responsiveness was monitored for at least 1 year. Postoperative CT scans were coregistered nonlinearly with preoperative MR images to determine the center coordinate and atlas-based anatomical localizations of all active contacts in the Montreal Neurological Institute (MNI) 152 space. Nineteen patients with drug-resistant epilepsy were followed up for at least a year following bilateral DBS electrode implantation targeting the ATN. Active contacts located more adjacent to the center of gravity of the anterior half of the ATN volume, defined as the anterior center (AC), were associated with greater seizure reduction than those not in this location. Intriguingly, the initially nonresponsive patients could end up with much improved seizure reduction by adjusting the active contacts closer to the AC at the final postoperative follow-up. Patients with stimulation targeting the AC may have a favorable seizure reduction. Moreover, the authors were able to obtain additional good outcomes after electrode repositioning in the initially nonresponsive patients. Purposeful and strategic trajectory planning to target this optimal region may predict favorable outcomes of ATN DBS.

Multivariate pattern classification on BOLD activation pattern induced by deep brain stimulation in motor, associative, and limbic brain networks

Deep brain stimulation (DBS) has been shown to be an effective treatment for movement disorders and it is now being extended to the treatment of psychiatric disorders. Functional magnetic resonance imaging (fMRI) studies indicate that DBS stimulation targets dependent brain network effects, in networks that respond to stimulation. Characterizing these patterns is crucial for linking DBS-induced therapeutic and adverse effects. Conventional DBS-fMRI, however, lacks the sensitivity needed for decoding multidimensional information such as spatially diffuse patterns. We report here on the use of a multivariate pattern analysis (MVPA) to demonstrate that stimulation of three DBS targets (STN, subthalamic nucleus; GPi, globus pallidus internus; NAc, nucleus accumbens) evoked a sufficiently distinctive blood-oxygen-level-dependent (BOLD) activation in swine brain. The findings indicate that STN and GPi evoke a similar motor network pattern, while NAc shows a districted associative and limbic pattern. The findings show that MVPA could be effectively applied to overlapping or sparse BOLD patterns which are often found in DBS. Future applications are expected employ MVPA fMRI to identify the proper stimulation target dependent brain circuitry for a DBS outcome.

Clinical and Kinematic Correlates of Favorable Gait Outcomes From Subthalamic Stimulation.

Objective: Gait and freezing of gait (FoG) are highly relevant to the outcomes of subthalamic nucleus deep brain stimulation (STN-DBS) in Parkinson's disease (PD). Previous studies pointed to variable response to combined dopaminergic and STN-DBS treatment. Here, we performed a prospective exploratory study on associations of preoperative clinical and kinematic gait measures with quantitative gait and FoG outcomes after STN-DBS implantation.Methods: We characterized 18 consecutive PD patients (13 freezers) before and after STN-DBS implantation. The patients received preoperative levodopa challenges (MedOff vs. MedOn) and a postoperative reassessment at 6 months from surgery in MedOn/StimOn condition. We correlated the FoG outcome, calculated as improvement of Freezing of Gait Assessment Course (FoG-AC) from baseline MedOff to 6-month follow-up MedOn/StimOn, with the levodopa response of preoperative clinical and kinematic gait measures. We considered measures with significant correlations for a multiple regression model.Results: We found that the postoperative gait and FoG outcomes were associated with the preoperative levodopa response of clinical and kinematic gait measures. In particular, preoperative levodopa sensitivity of FoG showed high correlation with a favorable quantitative FoG outcome. Among kinematic measures, preoperative levodopa response of stride length and range of motion showed high correlation with favorable FoG outcome. In addition, the preoperative levodopa sensitivity of FoG predicted postoperative FoG outcome with high accuracy (R2 = 0.952; 95% CI: 0.95–1.29; P < 0.001).Conclusions: Preoperative clinical and kinematic measures correlated with favorable postoperative gait and FoG outcomes. The findings should be reproduced in larger and independent cohorts to verify their predictive value.

A Comprehensive Review of Brain Connectomics and Imaging to Improve Deep Brain Stimulation Outcomes.

DBS is an effective neuromodulatory therapy that has been applied in various conditions, including PD, essential tremor, dystonia, Tourette syndrome, and other movement disorders. There have also been recent examples of applications in epilepsy, chronic pain, and neuropsychiatric conditions. Innovations in neuroimaging technology have been driving connectomics, an emerging whole-brain network approach to neuroscience. Two rising techniques are functional connectivity profiling and structural connectivity profiling. Functional connectivity profiling explores the operational relationships between multiple regions of the brain with respect to time and stimuli. Structural connectivity profiling approximates physical connections between different brain regions through reconstruction of axonal fibers. Through these techniques, complex relationships can be described in various disease states, such as PD, as well as in response to therapy, such as DBS. These advances have expanded our understanding of human brain function and have provided a partial in vivo glimpse into the underlying brain circuits underpinning movement and other disorders. This comprehensive review will highlight the contemporary concepts in brain connectivity as applied to DBS, as well as introduce emerging considerations in movement disorders. © 2020 International Parkinson and Movement Disorder Society.

Experts Debate What's Next for DBS for Depression

Experts Debate What's Next for DBS for Depression

Beneficial effect of 24-month bilateral subthalamic stimulation on quality of sleep in Parkinson\u2019s disease

BackgroundSubthalamic nucleus (STN) deep brain stimulation (DBS) improves quality of life (QoL), motor, and sleep symptoms in Parkinson’s disease (PD). However, the long-term effects of STN-DBS on sleep and its relationship with QoL outcome are unclear.MethodsIn this prospective, observational, multicenter study including 73 PD patients undergoing bilateral STN-DBS, we examined PDSleep Scale (PDSS), PDQuestionnaire-8 (PDQ-8), Scales for Outcomes in PD-motor examination, -activities of daily living, and -complications (SCOPA-A, -B, -C), and levodopa-equivalent daily dose (LEDD) preoperatively, at 5 and 24 months follow-up. Longitudinal changes were analyzed with Friedman-tests or repeated-measures ANOVA, when parametric tests were applicable, and Bonferroni-correction for multiple comparisons. Post-hoc, visits were compared with Wilcoxon signed-rank/t-tests. The magnitude of clinical responses was investigated using effect size.ResultsSignificant beneficial effects of STN-DBS were observed for PDSS, PDQ-8, SCOPA-A, -B, and -C. All outcomes improved significantly at 5 months with subsequent decrements in gains at 24 months follow-up which were significant for PDSS, PDQ-8, and SCOPA-B. Comparing baseline and 24 months follow-up, we observed significant improvements of PDSS (small effect), SCOPA-A (moderate effect), -C, and LEDD (large effects). PDSS and PDQ-8 improvements correlated significantly at 5 and 24 months follow-up.ConclusionsIn this multicenter study with a 24 months follow-up, we report significant sustained improvements after bilateral STN-DBS using a PD-specific sleep scale and a significant relationship between sleep and QoL improvements. This highlights the importance of sleep in holistic assessments of DBS outcomes.

Editors' note: Quality of life predicts outcome of deep brain stimulation in early Parkinson disease

In their prespecified secondary analysis of the EARLYSTIM trial, Dr. Schuepbach et al. sought to evaluate which demographic and clinical factors would predict an improvement in the Parkinson's Disease Questionnaire Summary Index (PDQ-39-SI). In summary, the investigators found that only subjective symptom severity at baseline was independently associated with improvement in the PDQ-39-SI—with worse baseline symptoms correlating with more responsiveness to subthalamic nucleus deep brain stimulation (STN-DBS). “Off” time, stage of the illness (advanced vs early), and more specific elements of the PDQ-39-SI may have also been useful for predicting responsiveness to STN-DBS, as Dr. Sidiropoulos writes in their response. On reevaluation of the patient-level data, Dr. Deuschl confirms that there is no difference in improvement in PDQ-39-SI based on the stage of PD. However, the duration of “off” time appears to strongly correlate with improvement after STN-DBS and is particularly noted in the advanced population. In conclusion, the investigators encourage clinicians to use these clinical predictors in the counseling of patients when STN-DBS is being considered. In their prespecified secondary analysis of the EARLYSTIM trial, Dr. Schuepbach et al. sought to evaluate which demographic and clinical factors would predict an improvement in the Parkinson's Disease Questionnaire Summary Index (PDQ-39-SI). In summary, the investigators found that only subjective symptom severity at baseline was independently associated with improvement in the PDQ-39-SI—with worse baseline symptoms correlating with more responsiveness to subthalamic nucleus deep brain stimulation (STN-DBS).

Author response: Quality of life predicts outcome of deep brain stimulation in early Parkinson disease.

We thank Dr. Sidiropoulos for the valuable comment on our article1 and agree that predictors are important for counseling patients. Reassuringly, the improvement of the quality of life (QoL) compared with only medical treatment for patients at an earlier stage, and for those at advanced stages, are very similar (24% and 27%, respectively),2,3 but the causes for this may differ. Although the only factor predicting the improvement of the QoL at follow-up was a poorer QoL at baseline,1 in the EARLYSTIM population, we found the duration of “off” time to be the most important predictor for improvement of the QoL in the advanced population.4 Not only the duration but also the differences of disease severity—both in the medication “on” and “off” states—after surgery may account for this. We found a number of factors in the advanced patients for which the change scores showed a correlation with QoL improvement (anxiety, depression, motor severity, and “off” time),4 but they cannot be regarded as predictors because the change is only known after surgery. The purpose of the recent publication was to look for such predictors and we found the baseline QoL summary index to be a predictor. This has changed our patient counseling: we recommend deep brain stimulation of the subthalamic nucleus for patients with early Parkinson disease if they have a disturbance in their QoL which is judged clinically relevant.

Reader response: Quality of life predicts outcome of deep brain stimulation in early Parkinson disease.

I congratulate Schuepbach et al.1 for their secondary analysis of data from the EARLYSTIM study; however, their results were not unexpected and almost predicted by the very stringent selection criteria of the original study. Although other studies indicated that “off” time is a predictor of improvement after deep brain stimulation (DBS),2 the analysis by Schuepbach et al.1 did not include “off” time as a baseline prognosticator. It would have also been interesting for the authors to assess which 39-item Parkinson's Disease Questionnaire (PDQ-39) subdomains were driving the PDQ composite score postoperatively.3 It should also be noted that disease duration has a different impact during different stages of life because younger patients may have better compensatory mechanisms, being able to tolerate disease for a longer time, as opposed to older patients.4 Moreover, levodopa response as a predictor was examined in a narrow window because the original EARLYSTIM study included only excellent responders (>50%).5 Consequently, many questions remain unanswered regarding the applicability of the EARLYSTIM results in a patient population of a broader age and disease severity spectrum, not to mention target selection (i.e., pallidal stimulation). Nevertheless, the EARLYSTIM study still represents a global paradigm shift in the way we approach DBS.

CAN DEEP BRAIN STIMULATION BE A THERAPEUTIC OPTION FOR DEMENTIA FROM PARKINSON'S DISEASE?

Parkinson's disease is a brain ailment that results in unintentional or uncontrollable movements, such as shaking, rigidity, and problems with balance and coordination. The objective of this report to review of the clinical outcomes of deep brain stimulation in Parkinson's disease dementia patients, and discuss if deep brain stimulation could be a treatment alternative in these people. After surgery, all patients' motor symptoms improved significantly, as did some non-motor symptoms. However, in four patients, the motor gains lasted only 2 or 3 years before the patients deteriorated with the appearance of end-stage difficulties, despite the fact that there were more continuous benefits that could not have been attained with medical treatment. The surviving patient had a great response till the final follow-up, 7 years following surgery.

Functional and Structural Connectivity Patterns Associated with Clinical Outcomes in Deep Brain Stimulation of the Globus Pallidus Internus for Generalized Dystonia.

Deep brain stimulation is a well-established treatment for generalized dystonia, but outcomes remain variable. Establishment of an imaging marker to guide device targeting and programming could possibly impact the efficacy of deep brain stimulation in dystonia, particularly in the absence of acute clinical markers to indicate benefit. We hypothesize that the stimulation-based functional and structural connectivity using resting-state fMRI and DTI can predict therapeutic outcomes in patients with generalized dystonia and deep brain stimulation. We performed a retrospective analysis of 39 patients with inherited or idiopathic-isolated generalized dystonia who underwent bilateral globus pallidus internus deep brain stimulation. After electrode localization, the volumes of tissue activated were modeled and used as seed regions for functional and structural connectivity measures using a normative data base. Resulting connectivity maps were correlated with postoperative improvement in the Unified Dystonia Rating Scale score. Structural connectivity between the volumes of tissue activated and the primary sensorimotor cortex was correlated with Unified Dystonia Rating Scale improvement, while more anterior prefrontal connectivity was inversely correlated with Unified Dystonia Rating Scale improvement. Functional connectivity between the volumes of tissue activated and primary sensorimotor regions, motor thalamus, and cerebellum was most correlated with Unified Dystonia Rating Scale improvement; however, an inverse correlation with Unified Dystonia Rating Scale improvement was seen in the supplemental motor area and premotor cortex. Functional and structural connectivity with multiple nodes of the motor network is associated with motor improvement in patients with generalized dystonia undergoing deep brain stimulation. Results from this study may serve as a basis for future development of clinical markers to guide deep brain stimulation targeting and programming in dystonia.

Long-term effects of bilateral pallidal deep brain stimulation in dystonia: a follow-up between 8 and 16\xa0years

ObjectiveObservational study to evaluate the long-term motor and non-motor effects of deep brain stimulation (DBS) of the globus pallidus internus (GPi) on medically refractory dystonia.BackgroundDystonia is a chronic disease affecting mainly young patients with a regular life expectancy and lifelong need for therapy. Pallidal DBS is an established treatment for severe isolated dystonia but long-term data are sparse.MethodsWe considered 36 consecutive patients with isolated generalized (n = 14) and cervical/segmental (n = 22) dystonia operated at Charité-University Hospital between 2000 and 2007 in a retrospective analysis for long-term outcome of pallidal DBS. In 19 of these patients, we could analyze dystonic symptoms and disability rated by the Burke–Fahn–Marsden Dystonia Rating scale (BFMDRS) at baseline, short-term (ST-FU, range 3–36 months) and long-term follow-up (LT-FU, range 93–197 months). Quality of life and mood were evaluated using the SF36 and Beck Depression Index (BDI) questionnaires.ResultsPatients reached an improvement in motor symptoms of 63.8 ± 5.7% (mean ± SE) at ST-FU and 67.9 ± 6.1% at LT-FU. Moreover, a significant and stable reduction in disability was shown following DBS (54.2 ± 9.4% at ST-FU and 53.8 ± 9.2% at LT-FU). BDI and SF36 had improved by 40% and 23%, respectively, at LT-FU (n = 14). Stimulation-induced adverse events included swallowing difficulties, dysarthria, and bradykinesia. Pulse generator (n = 3) and electrodes (n = 5) were revised in seven patients due to infection.ConclusionsPallidal DBS is a safe and efficacious long-term treatment for dystonia with sustained effects on motor impairment and disability, accompanied by a robust improvement in mood and quality of life.

Connectivity Patterns of Subthalamic Stimulation Influence Pain Outcomes in Parkinson's Disease.

Background: Pain is highly prevalent in Parkinson's disease and is associated with significant reduction in health-related quality of life. Subthalamic deep brain stimulation can produce significant pain relief in a subset of patients after surgery. However, the mechanism by which deep brain stimulation modulates sensory function in Parkinson's disease remains uncertain.Objective: To describe the motor and pain outcomes of deep brain stimulation applied to a series of patients with Parkinson's disease and to determine whether the structural connectivity between the volume of tissue activated and different regions of the brain was associated with the changes of these outcomes after surgery.Methods: Data from a long-term prospective cohort of 32 Parkinson's disease patients with subthalamic stimulation were combined with available human connectome to identify connections consistently associated with clinical improvement (Unified Parkinson Disease Rating Scale), pain intensity, and experimental cold pain threshold after surgery.Results: The connectivity between the volume of tissue activated and a distributed network of sensory brain regions (prefrontal, insular and cingulate cortex, and postcentral gyrus) was inversely correlated with pain intensity improvement and reduced sensitivity to cold pain after surgery (p < 0.01). The connectivity strength with the supplementary motor area positively correlated with motor and pain threshold improvement (p < 0.05).Conclusions: These data suggest that the pattern of the connectivity between the region stimulated and specific brain cortical area might be responsible, in part, for the successful control of motor and pain symptoms by subthalamic deep brain stimulation in Parkinson's disease.

Predictive factors for outcome of pallidal deep brain stimulation in cervical dystonia

ObjectivePrimary cervical dystonia (CD) is characterized by abnormal contractions of neck muscles. Globus pallidus internus deep brain stimulation (GPi-DBS) is recognized as an effective therapy for patients with refractory CD, but the prognostic factors need further research. Our study investigated the predictive factors of clinical outcomes in CD patients who underwent GPi-DBS. Patients and methodsPatients (n = 23) who underwent GPi-DBS at Chinese PLA General Hospital from March 2012 to April 2018 were included in our analysis. Their scores of Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui were acquired at baseline and at the last follow-up visit. Percent improvement in these scores were compared between the categorical variables. Correlations between outcomes and continuous demographic and clinical variables were calculated. ResultsPatients showed significant improvement in TWSTRS total (55.71 %), severity (48.75 %), disability (57.05 %), pain (63.67 %) scores and total Tsui score (46.07 %, all P ﹤0.001). Follow-up duration was positively correlated with percent improvement in TWSTRS total (rho = 0.594, P = 0.003), severity (rho = 0.581, P = 0.004) and disability (rho = 0.470, P = 0.023) scores. No significant differences in the outcomes were found between any pair of the categorical variables. ConclusionsFollow-up duration was the only independent factor correlated to the outcomes of GPi-DBS for CD patients. However, follow-up duration is an indefinite factor prior to surgery, thus further studies are needed before the final conclusions of prognostic factors are established.

Deep Brain Stimulation for Pain in the Modern Era: A Systematic Review.

Deep brain stimulation (DBS) has been considered for patients with intractable pain syndromes since the 1950s. Although there is substantial experience reported in the literature, the indications are contested, especially in the United States where it remains off-label. Historically, the sensory-discriminative pain pathways were targeted. More recently, modulation of the affective sphere of pain has emerged as a plausible alternative. To systematically review the literature from studies that used contemporary DBS technology. Our aim is to summarize the current evidence of this therapy. A systematic search was conducted in the MEDLINE, EMBASE, and Cochrane libraries through July 2017 to review all studies using the current DBS technology primarily for pain treatment. Study characteristics including patient demographics, surgical technique, outcomes, and complications were collected. Twenty-two articles were included in this review. In total, 228 patients were implanted with a definitive DBS system for pain. The most common targets used were periaqueductal/periventricular gray matter region, ventral posterior lateral/posterior medial thalamus, or both. Poststroke pain, phantom limb pain, and brachial plexus injury were the most common specific indications for DBS. Outcomes varied between studies and across chronic pain diagnoses. Two different groups of investigators targeting the affective sphere of pain have demonstrated improvements in quality of life measures without significant reductions in pain scores. DBS outcomes for chronic pain are heterogeneous thus far. Future studies may focus on specific pain diagnosis rather than multiple syndromes and consider randomized placebo-controlled designs. DBS targeting the affective sphere of pain seems promising and deserves further investigation.

Frameless Deep Brain Stimulation Surgery: A Single-Center Experience and Retrospective Analysis of Placement Accuracy of 220 Electrodes in a Series of 110 Patients

Background: Proper lead placement is considered one of the key factors in achieving a good clinical outcome in deep brain stimulation (DBS), but there is still considerable controversy surrounding the accuracy of the frameless in comparison to the frame-based technique. Objective: We report our single-center experience with DBS electrode placement to evaluate the accuracy of the frameless stereotactic system. Methods: We prospectively analyzed the data of 110 patients who underwent DBS surgery for Parkinson disease, dystonia, essential tremor, or refractory epilepsy. The final targets (FTs) of the 220 leads were: subthalamic nucleus, globus pallidus pars interna, ventralis intermedius nucleus, and anterior nuclei of thalamus in thalamus. A bilateral stereotactic approach using a combined identification of target based on preoperative images (MRI and CT scan fusion) and intra-operative micro-electrode recording (MER) were done. We collected and compared the coordinates of planned target (PT), the definitive expected target (ET) during MER, and the effective final location (FT) of the lead using the postoperative CT. Accuracy was assessed by both vector error (VE) and deviation from the PT. Results: The mean and SD from PTs was 0.78 ± 0.43 mm in the x direction, 0.68 ± 0.41 mm in the y direction, and 0.76 ± 0.41 mm in the z direction. Global VE was 1.43 ± 0.37. Conclusion: Frameless systems appear to be a reliable and accurate technique.

A pooled meta-analysis of GPi and STN deep brain stimulation outcomes for cervical dystonia.

To analyze deep brain stimulation (DBS) outcomes in patients with cervical dystonia (CD), the relationships between motor and disability/pain outcomes, and the differences in outcomes between globus pallidus internus (GPi) and subthalamic nucleus (STN) DBS, and to identify potential outcome predictors. A systematic literature search identified individual patient data of CD patients who underwent DBS and whose outcomes were assessed with the Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS). Then, we performed a pooled meta-analysis on this cohort. A review of 39 papers yielded 208 patients with individual TWSTRS scores and demographic information. At a mean follow-up period of 23.3months after either GPi or STN DBS, the TWSTRS total (58.8%), severity (53.9%), disability (61.3%), and pain (46.6%) scores significantly improved compared to baseline status (all p < 0.001). There were no significant outcome differences between short-term (< 23.3months) and long-term (≥ 23.3months). The TWSTRS outcomes after GPi and STN DBS were comparable, whereas these two targets showed different adverse effect profiles. The rates of responders to DBS according to the TWSTRS total and severity (defined as ≥ 25% improvement) were both 89%. Regression analyses demonstrated motor benefits associated with disability improvement more than pain relief (R2 = 0.345 and 0.195, respectively). No clinically meaningful predictors for DBS outcomes were identified. DBS improves motor symptoms, disability, and pain in CD patients and may provide sustained benefits over 2years. GPi and STN appear to be equally effective targets with different adverse effect profiles.

Deep Brain Stimulation for Tremor and Dystonia.

Deep brain stimulation (DBS) is the most commonly used surgical treatment for drug-refractory movement disorders such as tremor and dystonia. Appropriate patient selection along with target selection is important to ensure optimal outcome without complications. This review summarizes the recent literature regarding the mechanism of action, indications, outcome, and complications of DBS in tremor and dystonia. A comparison with other modalities of surgical interventions is discussed along with a note of the recent advances in technology. Future research needs to be directed to understand the underlying etiopathogenesis of the disease and the way in which DBS modulates the intracranial abnormal networks.