Deep Brain Stimulation Placement Research Articles

Deep Brain Stimulation of Bilateral Centromedian Thalamic Nuclei in Pediatric Patients with Lennox-Gastaut Syndrome: An Institutional Experience

IntroductionSurgical management of pediatric patients with non-lesional, drug-resistant epilepsy (DRE), including patients with Lennox-Gastaut Syndrome (LGS), remains a challenge given the lack of resective targets in most patients, and demonstrates seizure freedom rates <50% at 5-years. The efficacy of deep brain stimulation (DBS) is less certain in children than adults. This study examined clinical and seizure outcomes for pediatric patients with LGS undergoing DBS targeting of the centromedian thalamic nuclei (CMTN). MethodsIRB-approved retrospective analysis of patients ≤19-years with clinical diagnosis of LGS undergoing bilateral DBS placement to the CMTN from 2020-2021 by a single surgeon. ResultsFour females and 2 males, aged 6-19 years were identified. Before surgery, each child experienced at least 6-years of refractory seizures; 4 children experienced seizures since infancy. All took antiseizure medications at time of surgery. Five children had prior placement of a vagus nerve stimulator, 2 had previous corpus callosotomy. Mean length of stay following DBS was 2-days. No children experienced adverse neurological effects from implantation; mean follow-up time was 16.3 months. Four patients had >60% reduction in seizure frequency following surgery, 1 patient experienced 10% reduction, 1 patient demonstrated no change. No children reported worsening seizure symptoms post-surgery. ConclusionsOur study contributes to the sparse literature describing CMTN DBS for children with DRE from LGS. Our results suggest that CMTN DBS is a safe and effective therapeutic modality that should be considered as alternative or adjuvant therapy for this challenging patient population. Further studies with larger patient populations are warranted.

Application of deep brain stimulation for the treatment of childhood-onset dystonia in patients with MEPAN syndrome.

Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration (MEPAN) syndrome is a rare inherited metabolic condition caused by MECR gene mutations. This gene encodes a protein essential for fatty acid synthesis, and defects cause progressively worsening childhood-onset dystonia, optic atrophy, and basal ganglia abnormalities. Deep brain stimulation (DBS) has shown mixed improvement in other childhood-onset dystonia conditions. To the best of our knowledge, DBS has not been investigated as a treatment for dystonia in patients with MEPAN syndrome. Two children with MEPAN were identified as possible DBS candidates due to severe generalized dystonia unresponsive to pharmacotherapy. Temporary depth electrodes were placed in six locations bilaterally and tested during a 6-day hospitalization to determine the best locations for permanent electrode placement. The Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Barry-Albright Dystonia Scale (BADS) were used for preoperative and postoperative testing to quantitatively assess dystonia severity changes. Patient 1 had permanent electrodes placed at the globus pallidus internus (GPi) and pedunculopontine nucleus (PPN). Patient 2 had permanent electrodes placed at the GPi and ventralis intermedius nucleus of the thalamus (VIM). Both patients successfully underwent DBS placement with no perioperative complications and significant improvement in their BFMDRS score. Patient 2 also demonstrated improvement in the BADS. We demonstrated a novel application of DBS in MEPAN syndrome patients with childhood-onset dystonia. These patients showed clinically significant improvements in dystonia following DBS, indicating that DBS can be considered for dystonia in patients with rare metabolic disorders that currently have no other proven treatment options.

Intraoperative Trombone Playing during Awake Deep Brain Stimulator Placement.

Intraoperative Trombone Playing during Awake Deep Brain Stimulator Placement.

Frameless and fiducial-less, O-arm assisted navigation for deep brain stimulation placement using the Nexframe®. A technical note

O-arm® assisted navigation for placement of deep brain stimulation (DBS) electrodes using the Nexframe® device is a relatively new method that has been in use at many centers in the United States. However, no reports have described this operative technique in detail. In this technical report we describe the surgical nuances of this method in a stepwise approach. We also review and discuss the accuracy of this method in comparison to other methods of placing DBS electrodes.

Use of a Commercial 7-T MRI Scanner for Clinical Brain Imaging: Indications, Protocols, Challenges, and Solutions-A Single-Center Experience.

The first commercially available 7-T MRI scanner (Magnetom Terra) was approved by the FDA in 2017 for clinical imaging of the brain and knee. After initial protocol development and sequence optimization efforts in volunteers, the 7-T system, in combination with an FDA-approved 1-channel transmit/32-channel receive array head coil, can now be routinely used for clinical brain MRI examinations. The ultrahigh field strength of 7-T MRI has the advantages of improved spatial resolution, increased SNR, and increased CNR but also introduces an array of new technical challenges. The purpose of this article is to describe an institutional experience with the use of the commercially available 7-T MRI scanner for routine clinical brain imaging. Specific clinical indications for which 7-T MRI may be useful for brain imaging include brain tumor evaluation with possible perfusion imaging and/or spectroscopy, radiotherapy planning; evaluation of multiple sclerosis and other demyelinating diseases, evaluation of Parkinson disease and guidance of deep brain stimulator placement, high-detail intracranial MRA and vessel wall imaging, evaluation of pituitary pathology, and evaluation of epilepsy. Detailed protocols, including sequence parameters, for these various indications are presented, and implementation challenges (including artifacts, safety, and side effects) and potential solutions are explored.

PO-04-010 USE OF A LEADLESS PACEMAKER WITH BILATERAL DEEP BRAIN STIMULATORS

Deep brain stimulation (DBS) is a critical tool for the treatment of advanced, drug-refractory Parkinson’s disease using high-frequency stimulation of the subthalamic nucleus and globus pallidus internus. In patients with cooccurring needs for cardiac pacing, there is risk of electrical interference leading to oversensing. To minimize interaction, device manufacturers recommend a minimum distance of 6 inches between generators, which is not feasible with standard pacemaker (PPM) placement in the setting of bilateral DBS. In this case, we demonstrate leadless PPM placement in a patient with bilateral DBS and show absence of electrical interference with various DBS configurations and output. Demonstrate safety and efficacy of leadless pacemaker placement without electrical interference in patient with DBS n/a A 63 year-old female with history of Parkinson’s disease with bilateral DBS placement in 2015 presented with recurrent syncope. Patient was standing and washing dishes when she suddenly lost consciousness without prodrome. Telemetry demonstrated sinus rhythm with intermittent symptomatic junctional bradycardia. Transthoracic echocardiogram demonstrated normal ejection fraction with normal valve function. Reversible causes of syncope were ruled out and decision was made to implant a PPM. Given risk of interference with a standard PPM, a MICRA AV leadless PPM was implanted 4.8cm from the left DBS generator and programmed in VDD mode (Panel 1). To test for interference, bilateral DBS were programmed to unipolar stimulation with maximum output (5V at 135Hz and 2V at 185Hz). There was no evidence of noise or interference on MICRA AV EGM (Panel C) despite noise on surface ECG leads (Panel B). Patient’s symptoms improved with pacing and follow up device check showed no complications or interference. We demonstrate successful implant of a leadless PPM with AV synchrony (Micra AV) in patient with bilateral DBS. Despite placement less than 6 inches from DBS generators, there was no evidence of interference at maximum DBS voltage and frequency in both unipolar and bipolar configurations. Leadless PPM should be considered first line for patients with DBS, with appropriate pacing and absence of interference through a range of therapeutic outputs.

Construction of semi-supervised spatial projections to identify the source of beta- and high frequency oscillations in Parkinson's disease.

Traditional deep brain stimulation (DBS) treatment for Parkinson's disease (PD) targets the placement of DBS leads into subthalamic nucleus (STN). Extraction of neurobiomarkers from STN local field potential activity can be used for the optimization of DBS. Beta (12-30 Hz) and high frequency oscillations (200-450 Hz, HFO) of STN and their phase-amplitude coupling have been previously correlated with symptom severity in PD. The typical approach is to take bipolar derivations of electrode contacts in order to enhance recordings of local brain activity and suppress noise levels. This approach can often cancel the signals in correlated neighboring contacts and create ambiguity in which monopolar contact to select for the identification of the main source of the oscillatory signal. To improve local specificity and help identify the source of beta and HFO in terms of electrode contact, we propose a semi supervised blind-source separation method. This approach presents a novel perspective to investigate electrophysiology by projecting the recorded channels into a subspace of virtual channels. We show the contribution of each channel to the identified source and correlate the spatial information with imaging and postoperative programming parameters. We anticipate such a source identification strategy can be used in the future to investigate the distribution of beta and HFO on individual contacts of the DBS lead and can improve the interpretation of these signals.

Predictive nomogram for deep brain stimulation-related infections.

Infection is one of the important and frequent complications following implantable pulse generator and deep brain stimulation (DBS) electrode insertion. The goal of this study was to retrospectively evaluate and identify potential risk factors for DBS infections. From January 2015 to January 2021 in Qingdao municipal hospital (training cohort) and The First Affiliated Hospital of the University of Science and Technology of China (validation cohort), the authors enrolled patients with Parkinson disease who had undergone primary DBS placement or implantable pulse generator replacement. The cases were divided into infection or no-infection groups according to the 6-month follow-up. The authors used the logistic regression models to determine the association between the variables and DBS infection. Depending on the results of logistic regression, the authors established a nomogram. The calibration curves, receiver operating characteristic curve analysis, and decision curves were used to evaluate the reliability of the nomogram. There were 191 cases enrolled in the no-infection group and 20 cases in the infection group in the training cohort. The univariate logistic regression showed that BMI, blood glucose, and albumin were all significant predictors of infection after DBS surgery (OR 0.832 [p = 0.009], OR 1.735 [p < 0.001], and OR 0.823 [p = 0.001], respectively). In the crude, adjust I, and adjust II models, the three variables stated above were all considered to be significant predictors of infection after DBS surgery. The calibration curves in both training and validation cohorts showed that the predicted outcome fitted well to the observed outcome (p > 0.05). The decision curves showed that the nomogram had more benefits than the "All or None" scheme. The areas under the curve were 0.93 and 0.83 in the training and validation cohorts, respectively. The nomogram included BMI, blood glucose, and albumin, which were significant predictors of infection in patients with DBS surgery. The nomogram was reliable for clinical application.

Abstract 10052: Leadless Pacemaker and Deep Brain Stimulator: Proximity Without Interference

Introduction: Deep Brain Stimulator (DBS) treatment is a known form of treatment for advanced Parkinson’s disease refractory to medical therapy. With the current aging population, instances where cardiac implantable electronic devices are becoming more frequent. Due to risk of complications from implantation of both devices, literature has recommended keeping a minimum distance of 20cm (or 6in) between the two generators. In this case we have demonstrated a successful leadless pacemaker placement at 37mm apart without any complications. Case Report: 75 year old female with past medical history of essential tremor status post left VIM and VOA/VOP deep brain stimulator placement in 2019 presented to the emergency department with chief complaint of fall secondary to weakness. Electrocardiogram demonstrated Afib with RVR. Heparin was started for anticoagulation as the patient's CHADSVASC score was noted to be 5. Rate control was unsuccessful despite attempts with Metoprolol, digoxin loading, and max use of intravenous Cardizem. Cardioversion was not an option as the patient would need to commit to 4 weeks of uninterrupted therapeutic anticoagulation and be unable to undergo lung biopsy for new found lung mass. Extensive discussion was held with the patient and it was determined to proceed with AV nodal ablation with leadless pacemaker placement. Patient underwent successful placement of the Medtronic MC1VR01 US leadless pacemaker 37mm apart from the prior DBS device. Patient’s heart rate after the procedure remained stable at the lower rate of 80bpm with follow up device check in clinic showing no complications or interference among devices.

Long-Term Outcomes of Idiopathic and Acquired Dystonia After Pallidal Deep Brain Stimulation: A Case Series.

Among dystonia patients receiving globus pallidus internus (GPi) deep brain stimulation (DBS), long-term outcomes remain to be established. To report the long-term outcomes of GPi DBS in a patient cohort with idiopathic and acquired dystonia. In this long-term follow-up cohort, there were 4 patients with idiopathic dystonia and 2 patients with acquired dystonia. The Burke-Fahn-Marsden Dystonia Rating Scale was used to evaluate 6 consecutive patients preoperatively and at 6months, 12months, and the last follow-up. The relationship between etiology and clinical improvement was analyzed. Stimulation parameters were evaluated for similarities and differences among these patients. The mean follow-up of our cohort was 65.3months (median 40.5months). The average improvement in the Burke-Fahn-Marsden Dystonia Rating Scale (mean±SEM) were 56%±7.6, 67%±6.8 and 66%±9.7 at 6months, 12months, and the last follow-up, respectively. There was greater improvement during the long-term follow-up in the 4 patients with idiopathic dystonia than in the 2 patients with acquired dystonia. The 2 most ventral electrodes (contact 0 and 1) were activated in all 11 leads in this cohort. The average stimulation intensity, pulse width and frequency were 2.0±0.24mA, 252±43μs, and 99±6.0Hz, respectively. Isolated dystonia, either monogenic or idiopathic, usually responds better to GPi DBS than to acquired dystonia. Selection of patients by dystonia etiology, accurate placement of DBS leads in GPi targets, and proper stimulation programming are crucial to achieve better long-term outcomes.

Automatic extraction of upper-limb kinematic activity using deep learning-based markerless tracking during deep brain stimulation implantation for Parkinson's disease: A proof of concept study.

Optimal placement of deep brain stimulation (DBS) therapy for treating movement disorders routinely relies on intraoperative motor testing for target determination. However, in current practice, motor testing relies on subjective interpretation and correlation of motor and neural information. Recent advances in computer vision could improve assessment accuracy. We describe our application of deep learning-based computer vision to conduct markerless tracking for measuring motor behaviors of patients undergoing DBS surgery for the treatment of Parkinson’s disease. Video recordings were acquired during intraoperative kinematic testing (N = 5 patients), as part of standard of care for accurate implantation of the DBS electrode. Kinematic data were extracted from videos post-hoc using the Python-based computer vision suite DeepLabCut. Both manual and automated (80.00% accuracy) approaches were used to extract kinematic episodes from threshold derived kinematic fluctuations. Active motor epochs were compressed by modeling upper limb deflections with a parabolic fit. A semi-supervised classification model, support vector machine (SVM), trained on the parameters defined by the parabolic fit reliably predicted movement type. Across all cases, tracking was well calibrated (i.e., reprojection pixel errors 0.016–0.041; accuracies >95%). SVM predicted classification demonstrated high accuracy (85.70%) including for two common upper limb movements, arm chain pulls (92.30%) and hand clenches (76.20%), with accuracy validated using a leave-one-out process for each patient. These results demonstrate successful capture and categorization of motor behaviors critical for assessing the optimal brain target for DBS surgery. Conventional motor testing procedures have proven informative and contributory to targeting but have largely remained subjective and inaccessible to non-Western and rural DBS centers with limited resources. This approach could automate the process and improve accuracy for neuro-motor mapping, to improve surgical targeting, optimize DBS therapy, provide accessible avenues for neuro-motor mapping and DBS implantation, and advance our understanding of the function of different brain areas.

Recruitment of interictal- and ictal-like discharges in posterior piriform cortex by delta-rate (1–4 Hz) focal bursts in anterior piriform cortex in vivo

The development and propagation of seizure-related activity was studied in piriform cortex (PC) and areas in the medial temporal lobe to which it projects. In the urethane anesthetized adult rat at normal body temperature, tiny injections of convulsants in anterior PC (APC) generate an epileptogenic zone (focus) that can recruit electrographic seizures in untreated posterior PC (PPC) when bursts in the focus are paced at delta frequency (1–4 Hz) by stimulating the lateral olfactory tract. Epileptiform activity initiated by this ‘paced-recruitment’ procedure propagates throughout PPC and into other areas involved in mesial temporal lobe epilepsy (mTLE) at an exceedingly low velocity (< 1 mm/sec) as reported for focal seizures in human cortex. Proconvulsants increased the probability of recruiting electrographic seizures relative to disinhibiting agents that typically recruited interictal discharges. Through methods including realtime recording of current source-density (CSD) with vertical 22-site silicon-based electrodes, and membrane potential with transmembrane microelectrode pairs, insights were gained into mechanisms for epileptogenesis from PC. These findings also may apply to seizure initiation from epileptogenic zones in other areas that project to PPC in addition to APC. Findings from surgical studies indicating that PC plays a critical role in mTLE suggest that the results may be relevant to finding new approaches for blocking seizures from this common, virulent form of epilepsy. Immediate implications for treatment include the optimal placement and patterning of deep brain stimulation to increase its effectiveness for blocking seizures from mTLE while reducing the risk to vasculature from direct stimulation of PC.

Deep Brain Stimulation Surgery Using a Mobile Intraoperative CT Scanner.

IntroductionDeep brain stimulation (DBS) is widely used for the treatment of movement disorders. Precise placement of electrodes is critical for treatment success. The aim of this study was to analyze the accuracy of the intraoperative computer tomography (CT) images compared to that of a traditional fixed CT for patients undergoing DBS procedures.MethodsWe retrospectively analyzed the charts from 30 patients who underwent DBS. In group 1, 10 patients underwent electrode implantation surgery using a fixed CT scanner for pre- and post-operative (OP) images. In group 2, 20 patients underwent surgery using an intraoperative CT scanner for pre- and post-operative images, as well as a fixed CT scanner for post-operative images. We compared the average pre-operative localizer box registration error acquired in these two groups. We also analyzed, in group 2, the final electrode position given on each post-operative CT images. We compared the average Euclidean distances between each set of cartesian coordinates to assess target accuracy between both scanning methodologies.ResultsThirty patients had ages ranging from 40 to 88 years, with a median of 69 years old. In the 20 patients who utilized an intraoperative CT scanner pre-operatively in group 2, the mean error, given by the Medtronic software (Medtronic Minimally Invasive Therapies, Minneapolis, MN) with the Leksell frame on, was 0.37. For the 10 pre-operative scans with the stealth fixed CT scanner in group 1, the mean error was 0.44 (p = 0.13). In group 2, the average of the 20 Euclidean distances for each target, in those 20 patients who had post-operative images with both scanners, was 0.36.ConclusionWe concluded that the accuracy of the intraoperative CT scanner is comparable to the gold standard fixed CT scanner for DBS electrode planning and placement, as well as for positioning confirmation after the electrodes are in place.

Persistent Racial Disparities in Deep Brain Stimulation for Parkinson's Disease.

We sought to determine whether racial and socioeconomic disparities in the utilization of deep brain stimulation (DBS) for Parkinson's disease (PD) have improved over time. We examined DBS utilization and analyzed factors associated with placement of DBS. The odds of DBS placement increased across the study period, whereas White patients with PD were 5 times more likely than Black patients to undergo DBS. Individuals, regardless of racial background, with 2 or more comorbidities were 14 times less likely to undergo DBS. Privately insured patients were 1.6 times more likely to undergo DBS. Despite increasing DBS utilization, significant disparities persist in access to DBS. ANN NEUROL 2022;92:246–254

Deep Brain Stimulation (DBS) with Subthalamic Nucleus (STN) as Target for Pediatric Patients with PKAN

Dystonia in pantothenate kinase-associated neurodegeneration (PKAN) is progressive despite medication. Deep brain stimulation (DBS) was reported to effectively provide symptom relief. No consensus exists in candidate and target selection for DBS. We aimed to demonstrate effectiveness of subthalamic DBS (STN-DBS) placement in pediatric patients with PKAN. We reviewed consecutive series of pediatric patients diagnosed with PKAN and treated with STN-DBS from 2016 to 2019 in our institution. Each case was described in detail. Preoperative and postoperative Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) were assessed to evaluate functional improvement at follow-up. Seven pediatric patients were included. Mean age of initial onset was 0.6 ± 0.5 years and presentation to clinics was 6.6 ± 1.3 years. Mean preoperative BFMDRS was 73.3 ± 3.5. Following STN-DBS, for mean follow-up duration of 13.0 ± 10.7 months, mean BFMDRS was 37.3 ± 12.6, translating to score improvement of 36.0 ± 12.9 (P<0.001), and percentage improvement of 49.0 ± 18.0%. This case series demonstrated that STN-DBS is an effective symptom-based treatment for pediatric patients with PKAN.

429 Racial Disparities Persist Despite Increased Utilization of Deep Brain Stimulation Surgery for Parkinson’s Disease

INTRODUCTION: Deep brain stimulation (DBS) provides improved quality of life for properly selected individuals with Parkinson’s disease (PD). Though DBS is a widely accepted and efficacious therapy for PD, significant racial disparities have been reported in the access to DBS, particularly for Black patients. METHODS: The National Inpatient Sample (NIS) was queried to identify PD patients who underwent DBS placement between 2002 and 2018. We examined DBS utilization relative to PD admissions, patient characteristics over time, and whether ACA passage was associated with changes in insurance and DBS utilization among different racial/ethnic groups. RESULTS: In 2014-2018, the odds of PD patients receiving DBS therapy increased 56% compared to 2002-2005 (p &lt; 0.001). In a multivariate logistic regression analysis, the most important factors affecting the likelihood of DBS surgery were race, insurance status and the presence of comorbidities. Black PD patients were 1/5 as likely as White patients to undergo DBS placement (p &lt; 0.001). Individuals with = 2 comorbidities were 20 times less likely to undergo DBS. Patients insured privately compared to those insured by Medicare/Medicaid were 5.22 times as likely to undergo DBS. Passage of the ACA was associated with 2.62 times higher odds of DBS in 2010-2013 for Black PD patients compared to 2002-2005 (p = 0.008). During the period 2014-2018, Black PD patients were 2.33 times more likely to undergo DBS compared to the period 2002-2005 (p = 0.008). CONCLUSION: DBS is increasingly used for healthy, privately insured PD patients. Significant racial disparities persist in the use of DBS for PD despite a modest improvement following passage of the ACA, but prior to most of its implementation, indicating other factors contributed to this change.

92. Characteristics and Outcomes of Deep Brain Stimulation Device Related Infections: Experience from Quaternary Centers

BackgroundIncreasing use of deep brain stimulation (DBS) over the past 20 years is paralleled by a rise in DBS infections. There is a paucity of data on the diagnosis, management, and outcomes in such infections. We describe our center’s experience with DBS infections. MethodsAdults ( >18 years) diagnosed with DBS associated infection between January 1, 2000 and May 1, 2020 were retrospectively reviewed. Data on patient demographics, clinical presentation, microbiology, and management was collected. ResultsSeventy cases were identified (table 1). The mean age at diagnosis was 58.9 ± 16.5 years. The bulk were free of comorbidities. Parkinson’s disease and essential tremors were the most common indications for DBS placement. The median time from implantation to infection was 4 months [IQR 1,24]. The neurotransmitter and extension wires were the most frequently infected parts. A microbiological diagnosis was made in 89% of cases, 47% of which were polymicrobial. The most commonly identified organisms were Staphylococcus aureus, Cutibacterium acnes, and coagulase-negative staphylococci. For patients with deep infection, 71% had complete device extraction, 20% partial extraction, and 9% device retention; clinical cure at 3 months occurred in 97%, 64% and 100%, respectively (figure 1). On the other hand, 93% of patients with superficial infection had device retention; cure at 3 months was seen in 64% (figure 2). Suppressive oral antibiotics were rarely used, 45% of patients with partial extraction and 26% with device retention. DBS was reimplanted in 71% of patients after complete extraction and led to reinfection in 30% at 1 year follow up. Median time to reimplantation was 2.7 months. All patients who failed at 3 months in the partial extraction and device retention cohorts subsequently underwent complete device removal leading to clinical cure sustained at 1 year follow up. ConclusionAll patients who had complete extraction achieved clinical cure at 3-months follow-up, while high failure rates occurred in those with device retention. Most infections were polymicrobial and predominantly caused by gram-positive pathogens. Thirty percent of patients with re-implantation after complete device extraction developed re-infection within 1 year. Disclosures All Authors: No reported disclosures

DBS targeting for essential tremor using intersectional dentato-rubro-thalamic tractography and direct proton density visualization of the VIM: technical note on 2 cases.

Direct visualization of the ventral intermediate nucleus (VIM) of the thalamus on standard MRI sequences remains elusive. Therefore, deep brain stimulation (DBS) surgery for essential tremor (ET) indirectly targets the VIM using atlas-derived consensus coordinates and requires awake intraoperative testing to confirm clinical benefits. The objective of this study was to evaluate the utility of proton density (PD)-weighted MRI and tractography of the intersecting dentato-rubro-thalamic tract (DRTT) for direct "intersectional" targeting of the VIM in ET. DBS targets were selected by identifying the VIM on PD-weighted images relative to the DRTT in 2 patients with ET. Tremor reduction was confirmed with intraoperative clinical testing. Intended target coordinates based on the direct intersectional targeting technique were compared with consensus coordinates obtained with indirect targeting. Pre- and postoperative tremor scores were assessed using the Fahn-Tolosa-Marin tremor rating scale (TRS). Planned DBS coordinates based on direct versus indirect targeting of the VIM differed in both the anteroposterior (range 0 to 2.3) and lateral (range -0.7 to 1) directions. For 1 patient, indirect targeting-without PD-weighted visualization of the VIM and DRTT-would have likely resulted in suboptimal electrode placement within the VIM. At the 3-month follow-up, both patients demonstrated significant improvement in tremor symptoms subjectively and according to the TRS (case 1: 68%, case 2: 72%). Direct intersectional targeting of the VIM using PD-weighted imaging and DRTT tractography is a feasible method for DBS placement in patients with ET. These advanced targeting techniques can supplement awake intraoperative testing or be used independently in asleep cases to improve surgical efficiency and confidence.

A-65 Quality Analysis of Deep Brain Stimulation for Obsessive–Compulsive Disorder Using a Neuropsychological Assessment Battery

Abstract Objective We completed a case study to investigate whether there are cognitive changes after Deep Brain Stimulation (DBS) surgery in the treatment of refractory Obsessive–Compulsive Disorder (OCD) as an initiation of a quality analysis due to increased referrals for this procedure at our institution. Method We evaluated a 21-year-old male before and after bilateral nucleus accumbens DBS placement for OCD. His pre-operative neurosurgery evaluation and brain imaging were unremarkable. Post-operative imaging revealed stable changes of bilateral DBS lead placement. Pre and post-operative neuropsychological testing included measures of mental status, language, memory, attention, and executive functioning. Results A reliable change estimate was obtained for each test. There was no significant change in performance on the Mini-Mental State Exam, Boston Naming Test, Logical Memory I/II, Faces I, Rey Complex Figure Test (RCFT) immediate and delayed recall, Wisconsin Card Sorting Test-64, Trail Making Tests A &amp; B, Letter Fluency, Animal Fluency, and Stroop Color and Word Test (Stroop) color and color-word condition. There was significant decline for all California Verbal Learning Test-Second Edition trials (trials 1–5, short delay recall, and long delay recall) and RCFT recognition. There was significant improvement for the Stroop word condition. Conclusions. Given mixed findings, it is unclear the extent to which DBS impacted this patient’s overall cognitive functioning. Meanwhile, he showed improvement in OCD symptoms, to the degree that he could live alone, maintain employment, and independently manage daily activities. There is need for future studies to examine the cognitive effects of DBS for OCD, with larger samples and a control group.

Mood Regulatory Actions of Active and Sham Nucleus Accumbens Deep Brain Stimulation in Antidepressant Resistant Rats.

The antidepressant actions of deep brain stimulation (DBS) are associated with progressive neuroadaptations within the mood network, modulated in part, by neurotrophic mechanisms. We investigated the antidepressant-like effects of chronic nucleus accumbens (NAc) DBS and its association with change in glycogen synthase kinase 3 (GSK3) and mammalian target of rapamycin (mTOR) expression in the infralimbic cortex (IL), and the dorsal (dHIP) and ventral (vHIP) subregions of the hippocampus of antidepressant resistant rats. Antidepressant resistance was induced via daily injection of adrenocorticotropic hormone (ACTH; 100 μg/day; 15 days) and confirmed by non-response to tricyclic antidepressant treatment (imipramine, 10 mg/kg). Portable microdevices provided continuous bilateral NAc DBS (130 Hz, 200 μA, 90 μs) for 7 days. A control sham electrode group was included, together with ACTH- and saline-treated control groups. Home cage monitoring, open field, sucrose preference, and, forced swim behavioral tests were performed. Post-mortem levels of GSK3 and mTOR, total and phosphorylated, were determined with Western blot. As previously reported, ACTH treatment blocked the immobility-reducing effects of imipramine in the forced swim test. In contrast, treatment with either active DBS or sham electrode placement in the NAc significantly reduced forced swim immobility time in ACTH-treated animals. This was associated with increased homecage activity in the DBS and sham groups relative to ACTH and saline groups, however, no differences in locomotor activity were observed in the open field test, nor were any group differences seen for sucrose consumption across groups. The antidepressant-like actions of NAc DBS and sham electrode placements were associated with an increase in levels of IL and vHIP phospho-GSK3β and phospho-mTOR, however, no differences in these protein levels were observed in the dHIP region. These data suggest that early response to electrode placement in the NAc, irrespective of whether active DBS or sham, has antidepressant-like effects in the ACTH-model of antidepressant resistance associated with distal upregulation of phospho-GSK3β and phospho-mTOR in the IL and vHIP regions of the mood network.