Permanent Electrodes Research Articles

Lightweight deep learning model for automated STN localization using MER in Parkinson’s disease

Deep brain stimulation (DBS) of Subthalamic nucleus (STN), using a permanent electrode has emerged as an effective treatment for Parkinson’s disease patients. However, accurately localizing STN region during DBS surgery remains a challenging task. Microelectrode recording (MER) is used to identify STN by neurosurgeons. Nevertheless, manual interpretation of STN functional activity might prompt false alarms. Although the existing technology based on deep learning (DL) can outline the STN anatomical borders, it suffers from computational complexity and skewed findings. An end-to-end attention-based lightweight model with residual connections and soft thresholding is designed specifically for STN region detection. Scalogram and spectrogram images are generated from MER to mimic the observation of neurosurgeons and gather contextual information in a more intuitive manner. Proposed model exhibits a simplified architecture with only 15 layers, distinguishing it from previous DL models that tend to be more complex. Spatial attention helped to focus on relevant patterns within the data, while residual connections enhanced the gradient flow throughout the developed network. Soft thresholding offered noise reduction and robustness to signal variability. This approach eliminated the requirement for excessively deep layers and the necessity for separate feature extraction and classification stages by integrating them into a single pipeline. Our model identified STN with an accuracy of 97.42%. Proposed model outperformed 15 existing cutting-edge techniques. Our findings highlight the effectiveness of lightweight DL framework to achieve precise STN localization. The proposed method has significant potential in improving the efficiency of DBS surgery by reducing reliance on the neurosurgeon experience.

Rhythm matters: sinus and pace rhythm map significantly differ in endo/epicardial 3D electroanatomic mapping

Abstract Introduction Left ventricular substrate assessment utilizing ultra-high density multipolar catheters is frequently used to guide ablation procedures in patients with scar related ventricular tachycardia. However, 3D electroanatomic mapping is often performed during either sinus or paced rhythm. The effect of the modality (sinus vs. paced) used during mapping on substrate assessment remains elusive. Methods and Results We compared biventricular endo- and epicardial 3D high-density voltage and activation maps in sinus- and right ventricular-paced rhythm in domestic pigs. Data was acquired using a 20-polar mapping catheter with a cardiac tissue proximity filter based on catheter location and impedance measurements. Ventricular pacing (120 bmp) was performed with a permanent pacemaker electrode in right ventricular septal position, and high-density maps were acquired from the endo- and epicardium in sinus and paced rhythm (criterion for low voltage: <0.5 mV). Electroanatomical voltage and activation high-density (>6500 points per heart) mapping were performed with sufficient coverage in the right and left ventricles and the epicardium. The size of the low voltage area varied significantly between sinus and right ventricular-paced rhythm, particularly in epicardial mapping. In SR, the total low voltage was 7.2 ± 5.8%, while 11.1 ± 0.03% in paced rhythm. SR and paced maps revealed e.g. low voltage areas in the basal to apical anterior wall corresponding to the LAD regions, however, this was especially pronounced in sinus maps (e.g. pig 1: 64.2 cm²) compared to the paced rhythm map (e.g. pig 1: 32.8 cm²). Conclusion The extent of low voltage regions differed significantly in RV/LV, endo- and epicardially. Sinus maps showed the most accurate electrical representation of local voltage and corresponded correctly to local anatomical landmarks like e.g. the LAD with its surrounding epicardial fat tissue.3D biventricular epicardial voltage map

894 Comparison of Intraoperative Neural Changes During Tonic Versus High-Frequency Spinal Cord Stimulation in Chronic Pain Patients

INTRODUCTION: Chronic pain is a prevalent issue that may affect up to 34% of US adults, and spinal cord stimulation (SCS) is a promising therapy. However, SCS device selection remains a challenge because there are currently no objective biomarkers to evaluate chronic pain, or to predict which patients will be responders. METHODS: Intraoperative EEG signals were recorded in 24 chronic pain patients (14 women) during permanent SCS electrode placement surgery. Neural responses were captured with respect to tonic (60 Hz/300 µs) and high-frequency (1 kHz/30 µs) SCS paradigms in a randomized manner and correlated to Numeric Rating Scale (NRS) scores. All data were analyzed offline in MATLAB and SPSS v28.0.1.1. RESULTS: Our analyses for the main effects demonstrated a significant difference between cortical regions (F(2.88,57.7) = 7.60 , p < 0.001) and a marginal difference between stimulation conditions (F(2,40) = 2.970, p = 0.063). The post hoc analysis for these factors revealed that alpha/theta peak power ratio was significantly different between in central regions (C3-C4) between tonic and HF stimulation (p = 0.006) and temporal regions (T3-T4) between baseline and HF stimulation (p = 0.049). The comparison of NRS scores before and 3 months after surgery indicated a significant improvement in pain intensity (p < 0.001) at the group level. The neural features found to be significantly correlated with preoperative NRS scores in PFC (p = 0.036 and p = 0.025) and temporal regions (p = 0.041 and p = 0.012) under both stimulations. CONCLUSIONS: Our preliminary results support the possibility that different stimulation patterns affect the electrophysiological activity differently in various cortical regions. Such differences might account for the variability in pain suppression in patients with chronic pain treated with SCS. Future work will utilize this dataset to develop a machine learning classifier to support objective device selection strategies.

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.

Classification of DBS microelectrode recordings using a residual neural network with attention in the temporal domain

During the Deep Brain Stimulation (DBS) surgery for Parkinson’s disease (PD), the main goal is to place the permanent stimulating electrode into an area of the brain that becomes pathologically hyperactive. This area, called Subthalamic Nucleus (STN), is small and located deep within the brain. Therefore, the main challenge is the precise localization of the STN region, considering various measurement errors and artifacts. In this paper, we have designed and developed a computer-aided decision support system for neurosurgical DBS surgery. The implementation of this system provides a novel method for calculating the expected position of the stimulating electrode based on the recordings of the electrical activity of brain tissue. The artificial neural network with attention is used to classify the microelectrode recordings and determine the final position of the stimulating electrode within the STN area. Experiments have verified the utility and efficiency of our system. The tests were carried out on many recordings collected during DBS surgeries, giving encouraging results. The experimental results demonstrate that deep learning methods extended with self-attention blocks compete with the other solutions. They provide significant robustness to recording artifacts and improve the accuracy of the stimulating electrode placement.

Novel utilization of deep brain stimulation in the pedunculopontine nucleus with globus pallidus internus for treatment of childhood-onset dystonia

IntroductionDeep brain stimulation (DBS) is a well-documented therapy for dystonia utilized in many adult and pediatric movement disorders. Pedunculopontine nucleus (PPN) has been investigated as a DBS target primarily in adult patients with dystonia or dyskinesias from Parkinson’s disease, showing improvement in postural instability and gait dysfunction. Due to the difficulty in targeting PPN using standard techniques, it is not commonly chosen as a target for adult or pediatric pathology. There is no current literature describing the targeting of PPN in DBS for childhood-onset dystonia.MethodsTwo pediatric and one young adult patient with childhood-onset dystonia who underwent DBS implantation at our institution were identified. Patient 1 has Mitochondrial Enoyl CoA Reductase Protein-Associated Neurodegeneration (MEPAN) syndrome. Patient 2 has Glutaric Aciduria Type 1 (GA1). Patient 3 has atypical pantothenate kinase-associated neurodegeneration (PKAN). PPN was identified as a potential target for these patients due to axial or orofacial dystonia. Pre- and post-operative videos taken as part of routine clinical assessments were evaluated and scored on the Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) and Barry-Albright Dystonia Scale (BADS). All patients had permanent electrodes placed bilaterally in PPN and globus pallidus internus (GPi). A Likert scale on quality of life was also obtained from the patient/parents as applicable.ResultsSignificant programming was necessary over the first 3–12 months to optimize patients’ response to stimulation. All patients experienced at least a 34% improvement in the BFMDRS score. Patients 2 and 3 also experienced an over 30% improvement in BADS score. All patients/parents appreciated improvement in quality of life postoperatively.DiscussionDeep brain stimulation in PPN was safely and successfully used in two pediatric patients and one young adult patient with childhood-onset dystonia. These patients showed clinically significant improvements in BFMDRS scoring post operatively. This represents the first reported DBS targeting of PPN in pediatric patients, and suggests that PPN is a possible target for pediatric-onset dystonia with axial and orofacial symptoms that may be refractory to traditional pallidal stimulation alone.

Effect of Conductive Coating on Silver/Silver Chloride Electrodes for Cathodic Protection Application

Measurement of pipe to soil potential in a cathodic protection system is something that must be done which aims to monitor the performance of the installed cathodic protection system. The main measuring tool in measuring pipe to soil potential is the reference electrode. The stability of the reference electrode is important as a validation of the measurement results. So far, the stability of the reference electrode is very difficult to maintain due to frequent changes caused by the environment, especially for permanent reference electrodes that are buried in the underground or installed in seawater. Permanent reference electrode sensors commonly used in seawater is the Ag/AgCl reference electrode, but in fact the Ag/AgCl reference electrode is generally unstable and must be stabilized with a KCl solution and other problems have not been produced in Indonesia. This research will be carried out by adding a conductive layer to the Ag/AgCl electrode so that its stability can be increased. The sensor manufacturing process starts from pretreatment, electrolysis and product characterization. The results of the best coating thickness and weight gain experiments showed by the highest voltage variations and time variations (4000mV and 60 minutes). The presence of conductive solid material increases corrosion resistance from 0.00391 mm/year to 0.19549 mm/year and increases the stability of the Ag/AgCl layer ± 5 mV.

Deep brain stimulation in an adolescent with hypomyelination with atrophy of the basal ganglia and cerebellum due to a TUBB4A mutation: illustrative case.

Hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC) is a rare genetic disease due to a TUBB4A mutation, with motor features including dystonia. Deep brain stimulation (DBS) can be used to treat dystonia in pediatric populations, although the response is highly variable and preferential toward specific etiologies. A single pediatric subject with H-ABC received DBS using a staged procedure involving temporary depth electrode placement, identification of optimal stimulation targets, and permanent electrode implantation. After surgery, the patient significantly improved on both the Burke-Fahn-Marsden Dystonia Rating Scale and the Barry-Albright Dystonia Scale. The patient's response suggests that DBS can have potential benefit in H-ABC. TUBB4A mutations are associated with a variety of clinical phenotypes, and there is a lack of clearly identified targets for DBS, with this case being the second reported instance of DBS in this condition. The staged procedure with temporary depth electrode testing is recommended to identify optimal stimulation targets. The response seen in this patient implies that such a staged procedure may provide benefit in other conditions where DBS targets are currently unknown, including rare genetic or metabolic conditions associated with movement disorders.

0610 The effects of wakefulness promoting agents on neuronal activity in nucleus accumbens

Abstract Introduction Both modafinil and methylphenidate are frequently utilized for maintenance of wakefulness in narcolepsy and other sleep disorders. Both have been demonstrated to affect dopamine transporter, leading to an increase extracellular dopamine. Subsequent functional connectivity changes between nucleus accumbens and pallidum are noted. Animal studies demonstrate changes in neuronal activity with methylphenidate in nucleus accumbens. To our knowledge there has been no direct examination of human neural activity in nucleus accumbens after administration of modafinil or methylphenidate, compared to baseline. Methods Two subjects with placement of stereotactic electroencephalographic (sEEG) electrodes to identify optimal location for permanent deep brain stimulation electrodes in nucleus accumbens were given wakefulness promoting agents to optimize testing of stimulation sites during inpatient hospitalization. Assessment occurred at least 48 hours following surgical electrode insertion under inhaled general anesthesia. Retrospective analysis was performed on neural activity in nucleus accumbens during rest on and off medication. Frequency content was calculated in the following bands: delta (1-3 Hz), theta (4-7 Hz), alpha (8-12 Hz), beta (13-30 Hz), gamma (30-50 Hz), and high gamma (70-100 Hz). Power in each band is reported as the percentage contribution of each band to summed power across all bands. Results Total power was noted to be lower with both modafinil and methylphenidate. With modafinil, the beta band ratio was decreased (22.3% vs. 30.5%), the gamma band ratio was increased (24% vs. 22.4%), and the high gamma band was increased (39.5% vs. 32.9%). With methylphenidate, only the high gamma band was increased (40.3% vs. 22.9%). Conclusion Both methylphenidate and modafinil increase high gamma band neural activity in nucleus accumbens, while modafinil has additional effects on beta and gamma bands. Further assessment of modafinil and methylphenidate’s effects on neural activity are indicated to help better understand their mechanism of action and appropriate use as wakefulness promoting agents. Support (if any)

Elevated cerebrospinal fluid protein levels associated with poor short-term outcomes after spinal cord stimulation in patients with disorders of consciousness.

Spinal cord stimulation (SCS) is a promising treatment for patients with disorders of consciousness (DoC); however, the laboratory examinations and different electrodes (permanent #39286 vs. temporary percutaneous #3777, Medtronic, USA) that are associated with postoperative outcomes are unclear. The study aims to study the association between the change in postoperative cerebrospinal fluid (CSF) protein level and improvement in consciousness after SCS in DoC patients and to explore whether different electrodes were associated with elevated CSF protein levels. A total of 66 DoC patients who received SCS treatment from December 2019 to December 2021 were retrospectively analyzed. Patients were grouped according to their elevated CSF protein level. The clinical characteristics of the patients and SCS stimulation parameters were compared. The preoperative sagittal diameter of the spinal canal is the distance from the midpoint of the posterior border of the vertebral body to the midpoint of the posterior wall of the spinal canal at the level of the superior border of C3. The postoperative sagittal diameter of the spinal canal is the distance from the midpoint of the posterior edge of the vertebral body to the anterior edge of the stimulation electrode. Patients with improved postoperative CRS-R scores greater than 3 or who progressed to the MCS + /eMCS were classified as the improved group and otherwise regarded as poor outcome. We found that more DoC patients had elevated CSF protein levels among those receiving SCS treatment with permanent electrodes than temporary percutaneous electrodes (P = 0.001), and elevated CSF protein levels were significantly associated with a reduced sagittal diameter (P = 0.044). In DoC patients receiving SCS treatment, we found that elevated CSF protein levels (P = 0.022) and preoperative diagnosis (P = 0.003) were significantly associated with poor outcomes at 3 months. Logistic regression analysis showed that elevated CSF protein levels were significantly associated with poor outcomes (OR 1.008, 95% CI 1.001-1.016, P = 0.032). The results suggest that reducing the effect of electrode pads on anatomical changes may help improve the outcomes of DoC patients receiving SCS treatment. CSF protein levels are associated with poor postoperative outcomes and whether they are potential biomarkers in DoC patients receiving SCS treatment remain further exploration.

Video-urodynamics efficacy of sacral neuromodulation for neurogenic bladder guided by three-dimensional imaging CT and C-arm fluoroscopy: a single-center prospective study

To assess the efficacy of sacral neuromodulation (SNM) for neurogenic bladder (NB), guided by intraoperative three-dimensional imaging of sacral computed tomography (CT) and mobile C-arm fluoroscopy through video-urodynamics examination. We enrolled 52 patients with NB who underwent conservative treatment with poor results between September 2019 and June 2021 and prospectively underwent SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy. Video-urodynamics examination, voiding diary, quality of life questionnaire, overactive bladder symptom scale (OABSS) scoring, and bowel dysfunction exam were completed and recorded at baseline, at SNM testing, and at 6-month follow-up phases. Finally, we calculated the conversion rate from period I to period II, as well as the treatment efficiency and the occurrence of adverse events during the testing and follow-up phases. The testing phase of 52 NB patients was 18–60 days, with an average of (29.3 ± 8.0) days. Overall, 38 patients underwent SNM permanent electrode implantation, whose follow-up phase was 3–25 months, with an average of (11.9 ± 6.1) months. Compared with baseline, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased significantly in the testing phase. The daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased significantly in the testing phase. Besides, the voiding times, daily catheterization volume, quality of life score, OABSS score, bowel dysfunction score, maximum detrusor pressure before voiding, and residual urine volume decreased further from the testing to follow-up phase. Daily voiding volume, functional bladder capacity, maximum urine flow rate, bladder compliance, and maximum cystometric capacity increased further from testing to follow-up. At baseline, 10 ureteral units had vesicoureteral reflux (VUR), and 9 of them improved in the testing phase. Besides, there was 1 unit that further improved to no reflux during the follow-up phase. At baseline, 10 patients had detrusor overactivity (DO), and 8 of them improved in the testing phase. Besides, 1 patient’s symptoms further improved during the follow-up phase. At baseline, there were 35 patients with detrusor-bladder neck dyssynergia (DBND); 14 (40.0%) of them disappeared during the testing phase. Among 13 cases who had DBND in the testing phase, 6 (46.2%) disappeared during the follow-up phase. Of the 47 patients with detrusor-external sphincter dyssynergia (DESD) at baseline, 8 (17.0%) disappeared during the testing phase. Among 26 cases who had DESD in the testing phase, 6 (23.1%) disappeared during the follow-up phase. The effective rate of this study was 88.5% (46/52), and the conversion rate from phase I to phase II was 73.1% (38/52). Additionally, the efficacy in a short-term follow-up was stable. SNM guided by intraoperative three-dimensional imaging of sacral CT and mobile C-arm fluoroscopy is an effective and safe treatment option for NB in short time follow-up. It would be well improved in the bladder storage function, sphincter synergetic function and emptying efficiency by video-urodynamics examination in this study.Trial registration: Chinese Clinical Trial Registry. ChiCTR2100050290. Registered August 25 2021. http://www.chictr.org.cn/index.aspx.

Cattaneo-Christov Double Diffusion (CCDD) on Sutterby Nanofluid with Irreversibility Analysis and Motile Microbes Due to a RIGA Plate.

In this article, a Riga plate is exhibited with an electric magnetization actuator consisting of permanent magnets and electrodes assembled alternatively. This Riga plate creates an electric and magnetic field, where a transverse Lorentz force is generated that contributes to the flow along the plate. A new study field has been created by Sutterby nanofluid flows down the Riga plate, which is crucial to the creation of several industrial advancements, including thermal nuclear reactors, flow metres, and nuclear reactor design. This article addresses the second law analysis of MHD Sutter by nanofluid over a stretching sheet with the Riga plate. The Cattaneo–Christov Double Diffusion heat and mass flux have been created to examine the behaviour of relaxation time. The bioconvection of motile microorganisms and chemical reactions are taken into consideration. Similarity transformations are used to make the governing equations non-dimensional ordinary differential equations (ODE’s) that are subsequently solved through an efficient and powerful analytic technique, the homotopy analysis method (HAM). The effect of pertained variables on velocity, temperature, concentration, and motile microorganism distributions are elaborated through the plot in detail. Further, the velocity distribution enhances and reduces for greater value Deborah number and Reynold number for the two cases of pseudoplastic and dilatant flow. Microorganism distribution decreases with the augmented magnitude of Peclet number , Bioconvection Lewis number , and microorganism concentration difference number . The entropy production distribution is increased for the greater estimations of the Reynolds number and Brinkman parameter . Two sets of graphical outputs are presented for the Sutterby fluid parameter. Finally, for the justification of these outcomes, tables of comparison are made with various variables.

Entropy Analysis of Sutterby Nanofluid Flow over a Riga Sheet with Gyrotactic Microorganisms and Cattaneo–Christov Double Diffusion

In this article, a Riga plate is exhibited with an electric magnetization actuator consisting of permanent magnets and electrodes assembled alternatively. This exhibition produces electromagnetic hydrodynamic phenomena over a fluid flow. A new study model is formed with the Sutterby nanofluid flow through the Riga plate, which is crucial to the structure of several industrial and entering advancements, including thermal nuclear reactors, flow metres and nuclear reactor design. This article addresses the entropy analysis of Sutterby nanofluid flow over the Riga plate. The Cattaneo–Christov heat and mass flux were used to examine the behaviour of heat and mass relaxation time. The bioconvective motile microorganisms and nanoparticles are taken into consideration. The system of equations for the current flow problems is converted from a highly non-linear partial system to an ordinary system through an appropriate transformation. The effect of the obtained variables on velocity, temperature, concentration and motile microorganism distributions are elaborated through the plots in detail. Further, the velocity distribution is enhanced for a greater Deborah number value and it is reduced for a higher Reynolds number for the two cases of pseudoplastic and dilatant flows. Microorganism distribution decreases with the increased magnitude of Peclet number, Bioconvection Lewis number and microorganism concentration difference number. Two types of graphical outputs are presented for the Sutterby fluid parameter (β = −2.5, β = 2.5). Finally, the validation of the present model is achieved with the previously available literature.

Cervical Spinal Cord Stimulation for Trigeminal Neuralgia: a Narrative Review.

Trigeminal neuralgia (TN) is a chronic neuropathic pain condition affecting one or more divisions of the fifth cranial (trigeminal) nerve. TN is defined by recurrent unilateral electric shock-like pain that is abrupt in both onset and termination. The pain is triggered by innocuous sensory stimuli and is classified as either classic TN, related to vascular compression; secondary TN, due to a tumor along the trigeminal nerve or an underlying disease like multiple sclerosis; or idiopathic TN. Among the various therapies available for TN, carbamazepine remains the first-line treatment. Newer medications have demonstrated efficacy in patients who do not respond to or cannot tolerate carbamazepine. When medical management and neuroablative procedures fail, spinal cord stimulation (SCS) serves as a promising and popular option, with an estimated 34,000 SCS procedures performed annually worldwide. SCS employs the implantation of electrical leads in the epidural space to manage pain. A review of literature was conducted to explore the use of cervical spinal cord stimulation (SCS) for the treatment of trigeminal neuralgia. A MEDLINE/PubMed search using the search terms "spinal cord stimulation" and "trigeminal neuralgia" was employed to find any case reports and research studies (retrospective studies, double-blinded studies, observational studies) on the topic. No date limiters were used for the search. The initial search resulted in 76 non-duplicate entries from the database. After application of the search criteria, 58 studies were excluded because they were not relevant to the study. A further detailed review of the included articles was conducted by all the reviewers. During this phase of the review, additional 6 studies were excluded. A total of 11 studies were included: 7 case reports and 4 retrospective review studies. In the review, we discuss 7 different case reports on the use of cervical SCS for trigeminal neuralgia and an additional 4 retrospective studies reviewing outcomes and pain relief in patients who underwent treatment. The case reports and retrospective studies reviewed demonstrated that TN patients realized > 50% pain relief following permanent electrode implantation. In all the cases discussed, complications from SCS were rare and/or not reported. Additionally, most of the cases report that patients who had adequate pain relief from SCS were able to wean off, or significantly reduce, oral medications given the vast improvement in pain reduction. Cervical spinal cord stimulation (SCS) is a safe and effective procedure for patients with trigeminal neuralgia (TN) who have refractory pain despite the use of medications. In many cases, the procedure provides an adequate level of pain relief with very few complications or side effects. The vast majority of current research on the use of cervical SCS for TN currently consists of case reports and retrospective analysis. In order to further evaluate the efficacy of SCS for treatment, large-scale randomized controlled studies or observational studies need to be conducted to properly evaluate SCS as a treatment modality for trigeminal neuralgia.

Comparison of Electrophysiological and Radiological Subthalamic Nucleus Length and Volume.

To investigate the surgical value of MER recordings and improve surgical technique by demonstrating the consistency between preoperative radiological STN volume and intraoperative neurophysiological STN length. Sixty-one patients with PD were enrolled. The volumes of the STN were measured using magnetic resonance images 3-dimensional volume reconstructions of stereotactic magnetic resonance images. MER were performed in all patient and the maximal electrophysiologic length of the STN was recorded each patient. In the postoperative period, the permanent electrode was modeled and reconstructed in 3D, and the longest distance traveled in the STN was calculated. A total of 61 patients who underwent surgery between 2012-2022 were included in the study. Thirty-six (59%) of the patients were male, and 25 (41%) were female. A total of 122 STNs were performed with 166 electrodes. The most common end alignment used was center with 86. STN length averaged 4.9 mm (0-10.5 mm). The mean STN volume was 0.11 cm3. The STN Volume of men were significantly higher than women. The STN Length, Volume, and the target MER length showed a positive correlation significantly. With radiological advances, it is possible to better visualize the target points and define the boundaries better, and direct methods can be used more in making targeting plans. MER records obtained during surgery and STN dimensions in presurgical planning show compatibility, and it is seen that there may be differences between the right and left sides because of brain shifting. Although radiology is increasingly providing better support, electrophysiological recordings provides real-time information on the electrodes? locations and give the opportunity to surgical team choosing alternative target.

Metal-Molecule-Metal Junctions on Self-Assembled Monolayers Made with Selective Electroless Deposition.

Electronic transport through molecular-scale devices has been studied extensively for its extraordinary dimension superiority. Assembling such devices into large-scale functional circuits is crucial since the molecular tunnel junctions must be reliable, stable and reproducible during technological applications. In ideal circumstances, the device architecture should be designed such that the metal-molecule-metal (MMM) junctions can be analyzed by the more sensitive four point probe system. In this paper, we expound a delicate method to manufacture molecular junctions, which show excellent stability and reproducibility with high yields (>91 per cent). We form self-assembled monolayers (SAMs) on conductive Au thin film by microcontact printing and then generate robust covalently bound metal thin film electrodes on top of the SAMs by selective electroless deposition. Following MMM junction formation, a photoresist is coated and wells are opened on each feature by lithography. Then, Au thin film, as a permanent top electrode, is deposited into the photolithographically defined well. Conductivity analyzations were carried out on the 50 μm square junctions by the four point probe measurement, and the results showed reproducible tunneling I-V characteristics. This method reveals an approach not only offering a unique vehicle to investigate the electrical properties of molecule ensembles in MMMs, but also making a significant step toward MMM applications at the device level.

Pre-motor versus motor cerebral cortex neuromodulation for chronic neuropathic pain

Electrical stimulation of the cerebral cortex (ESCC) has been used to treat intractable neuropathic pain for nearly two decades, however, no standardized approach for this technique has been developed. In order to optimize targeting and validate the effect of ESCC before placing the permanent grid, we introduced initial assessment with trial stimulation, using a temporary grid of subdural electrodes. In this retrospective study we evaluate the role of electrode location on cerebral cortex in control of neuropathic pain and the role of trial stimulation in target-optimization for ESCC. Location of the temporary grid electrodes and location of permanent electrodes were evaluated in correlation with the long-term efficacy of ESCC. The results of this study demonstrate that the long-term effect of subdural pre-motor cortex stimulation is at least the same or higher compare to effect of subdural motor or combined pre-motor and motor cortex stimulation. These results also demonstrate that the initial trial stimulation helps to optimize permanent electrode positions in relation to the optimal functional target that is critical in cases when brain shift is expected. Proposed methodology and novel results open a new direction for development of neuromodulation techniques to control chronic neuropathic pain.

Rate of Onset as a Determinant of Abuse Potential Assessment Using Intracranial Self‐Stimulation in Rats

Background Intracranial self-stimulation (ICSS) is one procedure that has been used to evaluate abuse potential of drugs, and as with more commonly used drug self-administration procedures, ICSS is especially sensitive to drugs that activate the mesolimbic dopamine system. Drug self-administration studies have shown that abuse potential can also be influenced by temporal parameters, and especially rate of onset; however, the degree to which rate of onset influences abuse-potential metrics in ICSS procedures has not been systematically examined. To address this issue, this study evaluated three dopamine transporter (DAT) inhibitors that have different onset rates and were shown previously to maintain different peak break points in rhesus monkeys responding under a progressive-ratio schedule (cocaine > WIN35428 > RTI-31 for both rate of onset and break point). In ICSS, abuse potential is generally indicated when a drug increases low rates of responding maintained by low levels of brain stimulation, a phenomenon called “ICSS facilitation”. We hypothesized that these three DAT inhibitors would facilitate ICSS different time courses, but the degree to which rate of onset might influence peak facilitation was unknown. Methods Adult male and female Sprague-Dawley rats (n = 5-7 per drug) were surgically implanted with permanent stainless-steel electrodes targeting the medial forebrain bundle and trained to respond on a lever to receive electrical brain stimulation. Behavioral sessions were organized in components consisting of ten one-minute frequency trials over a range of brain-stimulation frequencies (56-158 Hz), such that a full curve relating brain-stimulation frequency to response rate could be determined every 10 min. On test days, three baseline ICSS components were followed first by intraperitoneal drug injection and then immediately by 12 consecutive test components (120 min). Additional pairs of test components were initiated at 300 and 1440 minutes post-injection. The drugs and dose ranges tested were as follows: cocaine HCl (1.0 - 10 mg/kg), WIN35428 (0.10 – 0.32 mg/kg), and RTI-31 (0.032 – 0.10 mg/kg). All drugs were tested up to doses that produced peak levels of ICSS facilitation; higher doses disrupted responding and produced stereotypies. Results Under baseline conditions, brain stimulation maintained a frequency-dependent increase in reinforcement rates. All three drugs dose-dependently and robustly facilitated ICSS, shifting ICSS frequency-rate curves to the left and increasing the total number of stimulations per component when data were collapsed across all frequencies. Consistent with previous studies, the rate of onset for ICSS facilitation was fastest for cocaine, slower for WIN35428, and slowest for RTI-31. Cocaine also had the shortest duration of action and the lowest potency, whereas RTI-31 had the longest duration of action and highest potency. However, despite these differences in time course and potency, peak ICSS facilitation was not statistically different across drugs. Conclusions These results suggest that ICSS studies should evaluate rate of onset as well as peak ICSS facilitation in reaching conclusions about overall abuse potential of a test drug.

Design of an Ionic Conductor as Permanent Electrode for Monitoring Cathodic Protection System performance.

The most dominant used method for protecting the bottom of a tank is impressing a current cathodic protection (ICCP). Monitoring the CP system is critical to maintain and extend the service life of the exterior bottom of the storage tank. The bottom of the tank usually located on or near the surface of the ground and in contact with materials used to support the tank and so presents a corrosion challenge. This work presents a successful design of an ionic conductor that can be used as a monitor procedure of ICCP system for ground storage tanks bottom. The new ionic conductor system offers an accurate and efficient performance compared with old copper/ copper sulphate electrode monitoring system. The risks failure of permanent electrodes including cables disconnection and electrode dryness are increasing. Ionic conductors were used to insure proper potential monitoring. The new ionic conductor system scheme has the features of lower cost and less installation time over conventional methods.

Deep convolutional neural network for the automated detection of Subthalamic nucleus using MER signals

BackgroundDeep brain stimulation (DBS) surgery has been extensively conducted for treating advanced Parkinson's disease (PD) patient's symptoms. DBS hinges on the localization of the subthalamic nucleus (STN) in which a permanent electrode should be accurately placed to produce electrical current. Microelectrode recording (MER) signals are routinely recorded in the procedure of DBS surgery to validate the planned trajectories. However, manual MER signals interpretation with the goal of detecting STN borders requires expertise and prone to inter-observer variability. Therefore, a computerized aided system would be beneficial to automatic detection of the dorsal and ventral borders of the STN in MER. New methodIn this study, a new deep learning model based on convolutional neural system for automatic delineation of the neurophysiological borders of the STN along the electrode trajectory was developed. Comparison with existing methodsThe proposed model does not involve any conventional standardization, feature extraction or selection steps. ResultsPromising results of 98.67% accuracy, 99.03% sensitivity, 98.11% specificity, 98.79% precision and 98.91% F1-score for subject based testing were achieved using the proposed convolutional neural network (CNN) model. ConclusionsThis is the first study on the analysis of MER signals to detect STN using deep CNN. Traditional machine learning (ML) algorithms are often cumbersome and suffer from subjective evaluation. Though, the developed 10-layered CNN model has the capability of extracting substantial features at the convolution stage. Hence, the proposed model has the potential to deliver high performance on STN region detection which shows perspective in aiding the neurosurgeon intraoperatively.