Seizure Risk Associated With the Use of Transcranial Magnetic Stimulation for Coma Recovery in Individuals With Disordered Consciousness After Severe Traumatic Brain Injury.

OBJECTIVE: Repetitive Transcranial Magnetic Stimulation (rTMS) is emerging as a promising treatment for persons with disorder of consciousness (DoC) following traumatic brain injury (TBI). Clinically, however, there are concerns about rTMS exacerbating baseline seizure risk. To advance understanding of risks, this article reports evidence of DoC-TBI rTMS-related seizure risk. SETTING: Acute and sub-acute hospitals. PARTICIPANTS: Persons in states of DoC 6.5 months to 15 years after TBI (n = 20) who received active rTMS (n = 17) or placebo rTMS (n = 3). After completing placebo procedures, placebo participants completed active rTMS procedures. These 3 participants are included in the active group. DESIGN: Meta-analysis of data from 3 clinical trials; 2 within-subject, 1 double blind randomized placebo-controlled. Each trial used the same rTMS protocol, provided at least 30 rTMS sessions, and delivered rTMS to the dorsolateral prefrontal cortex. MAIN MEASURES: During each study's rTMS treatment phase, seizure occurrences were compared between active and placebo groups using logistic regression. After stratifying active group by presence/absence of seizure occurrences, sub-groups were compared using contingency chi-square tests of independence and relative risk (RR) ratios. RESULTS: Two unique participants experienced seizures (1 active, 1 placebo). Post seizure, both participants returned to baseline neurobehavioral function. Both participants received antiepileptics during remaining rTMS sessions, which were completed without further seizures. rTMS-related seizure incidence rate is 59 per 1000 persons. Logistic regression revealed no difference in seizure occurrence by treatment condition (active vs placebo) or when examined with seizure risk factors (P > .1). Presence of ventriculoperitoneal shunt elevated seizure risk (RR = 2.0). CONCLUSION: Collectively, findings indicate a low-likelihood that the specified rTMS protocol exacerbates baseline seizure rates in persons with DoC after TBI. In presence of VP shunts, however, rTMS likely elevates baseline seizure risk and mitigation of this increased risk with pharmacological seizure prophylaxis should be considered.

Cortical sites critical to language function act as connectors between language subnetworks.

Historically, eloquent functions have been viewed as localized to focal areas of human cerebral cortex, while more recent studies suggest they are encoded by distributed networks. We examined the network properties of cortical sites defined by stimulation to be critical for speech and language, using electrocorticography from sixteen participants during word-reading. We discovered distinct network signatures for sites where stimulation caused speech arrest and language errors. Both demonstrated lower local and global connectivity, whereas sites causing language errors exhibited higher inter-community connectivity, identifying them as connectors between modules in the language network. We used machine learning to classify these site types with reasonably high accuracy, even across participants, suggesting that a site's pattern of connections within the task-activated language network helps determine its importance to function. These findings help to bridge the gap in our understanding of how focal cortical stimulation interacts with complex brain networks to elicit language deficits.

Case-based explanation of standard work tools for selective dorsal rhizotomy for cerebral palsy.

OBJECTIVE: Spasticity is a challenging feature of cerebral palsy (CP) that may be managed with selective dorsal rhizotomy (SDR). Although standard work tools (SWTs) have recently been utilized to inform a standard of care for neurosurgical procedures, no SWTs for SDR have been previously described. The authors present the multidisciplinary approach SWTs for SDR used at their institutions to promote consistency in the field and minimize complication rates. METHODS: A multidisciplinary approach was used to define all steps in the SDR pathway. Preoperative, intraoperative, and postoperative workflows were synthesized, with specific efforts to improve mobility through inpatient rehabilitation and minimize infection. RESULTS: The SWTs have been implemented at two institutions for 7 years. An illustrative case of a patient aged 3 years 10 months with a history of premature birth at 29 weeks, spastic-diplegic CP, right-sided periventricular leukomalacia, and developmental delay who underwent L2-S1 SDR is presented. CONCLUSIONS: The authors detail SWTs for SDR developed by a multidisciplinary team with specific steps at all points in the patient pathway. The illustrative case emphasizes that SWTs may help ensure the safety of SDR while maximizing its long-term efficacy for individuals with CP.

A review of prospective studies regarding percutaneous peripheral nerve stimulation treatment in the management of chronic pain.

Conventionally, peripheral nerve stimulation (PNS) for treatment of chronic pain has involved a two-stage process: a short-term (e.g., 7 days) trial and, if significant pain relief is achieved, a permanent PNS system is implanted. A percutaneous PNS treatment is now available where a coiled lead may be implanted for up to 60 days with the goal of producing sustained relief. In the present review, published prospective trials using percutaneous PNS treatment were identified and synthesized. The collected evidence indicates that percutaneous PNS treatment for up to 60 days provides durable clinically significant improvements in pain and pain interference. Similar efficacy across diverse targets and etiologies supports the broad applicability for use within the chronic pain population using this nonopioid technology.

What is this review about? This review looks at a drug-free way to treat chronic pain called percutaneous peripheral nerve stimulation (PNS). Percutaneous means it is placed through the skin. PNS applies small amounts of electricity to the nerves to reduce chronic pain. Most PNS systems involve a two-step process. A short trial is first performed to see if a patient has pain relief. A permanent system is then placed if the person had pain relief. Percutaneous PNS treatments are different. They use a thin wire called a lead placed in the body for up to 60 days. The lead is taken out at the end of the treatment period. Studies have shown that this type of PNS treatment can reduce chronic pain even after the treatment is over. No previous article has collected all these studies of percutaneous PNS in one place.What evidence was gathered? This review found evidence from studies on treatment of chronic pain. Pain types included shoulder pain, neuropathic pain and low back pain. It found that percutaneous PNS treatment for up to 60 days can reduce pain and how pain interferes with daily life.How can these data lead to better care for patients? These findings mean that percutaneous PNS treatments could be a useful, non-drug option for many types of chronic pain.

Back Pain in the Era of Opioid Restriction and Implications for Neurosurgeons Based on Qualitative Findings From a Rural State.

Historically, back pain has been an inciting complaint for the initiation of opioids. Aggressive marketing of opioids to treat back pain coupled with the initiation of pain being treated as "the fifth vital sign" contributed to the emerging opioid crisis in the USA. West Virginia (WV) has long been considered the epicenter of the crisis. In 2018, the WV legislature passed a bill that placed prescribing limits on opioids. Our group set out to investigate the impacts of opioid prescribing restrictions through a sequential, mixed methods study evaluating prescription trends and stakeholder experiences. These stakeholder experiences generated emergent themes regarding the evolution of the opioid crisis up to and beyond the implementation of the bill, which is of relevance to neurosurgeons and back pain treatment. This study explores those findings for a neurosurgical audience. This study consisted of open-ended, semi-structured interviews with a purposive sample of 50 physicians, pharmacists, and patients in WV. Interviews were recorded and transcribed verbatim. Content analysis was utilized as the methodological orientation. Five theoretical domains relevant to the treatment of back pain emerged, describing the prevalence of opioid use, barriers to access care, the importance of opioids for function in resource-poor rural areas, disconnected and siloed care, and patient views on the impacts of pain care gaps and solutions. Spinal pain care in rural WV is complex due to identified challenges. Care siloing factors in suboptimal spinal pain care. Future work should define, implement, and assess the real-world effectiveness of treatment paradigms for the full spectrum of surgical and non-surgical back pain complaints. Neurosurgeons should be present in this arena.

Occipital nerve stimulation in pediatric patients with refractory occipital neuralgia.

PURPOSE: Occipital neuralgia (ON) is a disabling problem within the pediatric population. Many of these patients fail medical therapies and continue to suffer without further surgical management. Occipital nerve stimulation (ONS) is used to treat ON in the adult population leading to a 72-89% reduction in pain; however, there are limited studies regarding its use in the pediatric population. In this study, we examined the outcomes of ONS in pediatric patients with medically refractory ON. METHODS: We performed a chart review of pediatric patients at our institution who have undergone ONS for the same indications. RESULTS: We identified 3 patients at our institution who underwent ONS trial and/or permanent implantation for ON. One patient had complete pain relief after the trial and declined permanent implantation. The other patient had fewer attacks compared to his pre-trial baseline and controlled them by adjusting his permanent implant stimulation settings. The last patient had near complete relief of her symptoms and no longer required any pain medication. CONCLUSION: Our study highlights the paucity of studies evaluating the utility of ONS in the pediatric ON population. Limited data from both the literature and our institution's experience reveal that pediatric patients may benefit from trial and/or permanent implantation of ONS for medically refractory ON pain.

Predictors of salvage therapy for parasagittal meningiomas treated with primary surgery, radiosurgery, or surgery plus adjuvant radiotherapy.

OBJECTIVE: Parasagittal meningiomas (PM) are treated with primary microsurgery, radiosurgery (SRS), or surgery with adjuvant radiation. We investigated predictors of tumor progression requiring salvage surgery or radiation treatment. We sought to determine whether primary treatment modality, or radiologic, histologic, and clinical variables were associated with tumor progression requiring salvage treatment. METHODS: Retrospective study of 109 consecutive patients with PMs treated with primary surgery, radiation (RT), or surgery plus adjuvant RT (2000-2017) and minimum 5 years follow-up. Patient, radiologic, histologic, and treatment data were analyzed using standard statistical methods. RESULTS: Median follow up was 8.5 years. Primary treatment for PM was surgery in 76 patients, radiation in 16 patients, and surgery plus adjuvant radiation in 17 patients. Forty percent of parasagittal meningiomas in our cohort required some form of salvage treatment. On univariate analysis, brain invasion (OR: 6.93, p < 0.01), WHO grade 2/3 (OR: 4.54, p < 0.01), peritumoral edema (OR: 2.81, p = 0.01), sagittal sinus invasion (OR: 6.36, p < 0.01), sagittal sinus occlusion (OR: 4.86, p < 0.01), and non-spherical shape (OR: 3.89, p < 0.01) were significantly associated with receiving salvage treatment. On multivariate analysis, superior sagittal sinus invasion (OR: 8.22, p = 0.01) and WHO grade 2&3 (OR: 7.58, p < 0.01) were independently associated with receiving salvage treatment. There was no difference in time to salvage therapy (p = 0.11) or time to progression (p = 0.43) between patients receiving primary surgery alone, RT alone, or surgery plus adjuvant RT. Patients who had initial surgery were more likely to have peritumoral edema on preoperative imaging (p = 0.01). Median tumor volume was 19.0 cm3 in patients receiving primary surgery, 5.3 cm3 for RT, and 24.4 cm3 for surgery plus adjuvant RT (p < 0.01). CONCLUSION: Superior sagittal sinus invasion and WHO grade 2/3 are independently associated with PM progression requiring salvage therapy regardless of extent of resection or primary treatment modality. Parasagittal meningiomas have a high rate of recurrence with 80.0% of patients with WHO grade 2/3 tumors with sinus invasion requiring salvage treatment whereas only 13.6% of the WHO grade 1 tumors without sinus invasion required salvage treatment. This information is useful when counseling patients about disease management and setting expectations.

Benefits of subthalamic nucleus deep brain stimulation on visually-guided saccades depend on stimulation side and classic paradigm in Parkinson's disease.

OBJECTIVE: We aimed to gain further insight into previously reported beneficial effects of subthalamic nucleus deep brain stimulation (STN-DBS) on visually-guided saccades by examining the effects of unilateral compared to bilateral stimulation, paradigm, and target eccentricity on saccades in individuals with Parkinson's disease (PD). METHODS: Eleven participants with PD and STN-DBS completed the visually-guided saccade paradigms with OFF, RIGHT, LEFT, and BOTH stimulation. Rightward saccade performance was evaluated for three paradigms and two target eccentricities. RESULTS: First, we found that BOTH and LEFT increased gain, peak velocity, and duration compared to OFF stimulation. Second, we found that BOTH and LEFT stimulation decreased latency during the gap and step paradigms but had no effect on latency during the overlap paradigm. Third, we found that RIGHT was not different compared to OFF at benefiting rightward saccade performance. CONCLUSIONS: Left unilateral and bilateral stimulation both improve the motor outcomes of rightward visually-guided saccades. Additionally, both improve latency, a cognitive-motor outcome, but only in paradigms when attention does not require disengagement from a present stimulus. SIGNIFICANCE: STN-DBS primarily benefits motor and cognitive-motor aspects of visually-guided saccades related to reflexive attentional shifting, with the latter only evident when the fixation-related attentional system is not engaged.

Postmortem Protocols of Implantable Neurosurgical Devices: A Cross-Sectional Survey.

BACKGROUND: Implantable devices are increasingly more common for management of movement disorders, pain, and epilepsy. These devices are often complex and constructed of nonbiodegradable or hazardous materials. Therefore, proper postmortem handling of these devices is exceedingly important. Unfortunately, there is no consolidated resource available for postmortem neuromodulation device protocols. Thus, we surveyed and catalogued the protocols for implantable devices to summarize proper postmortem device protocols for implantable neurosurgical devices currently on the market. METHODS: We performed a cross-sectional study of companies producing commonly implanted neurosurgical devices. Using information from company websites, user manuals, and catalogs we categorized devices into 3 groups: A (formal recommendation for explantation), B (recommendation for explantation without formal company protocol), and C (explantation is not necessary). We then compiled the data into a stoplight diagram, providing a clear postmortem disposal algorithm for each device category. RESULTS: Twelve companies were queried regarding 46 devices. Postmortem protocols were available for 50% (23/46) of devices; the remaining devices did not have formal recommendations. Overall, 50% of devices were classified as category A "red light" on the stoplight diagram based on recommendations, 10.9% as category B "yellow light," and the remaining 39.1% were classified as category C "green light" indicating they are safe to bury or cremate. CONCLUSIONS: Evolution in therapies and growth in functional neurosurgery has expanded the range of implantable neurosurgical devices. We provide an educational document summarizing their postmortem protocols. This resource aims to aid health-care providers and encourage proper disposal practices during burial or cremation.

High-Gamma Activity Is Coupled to Low-Gamma Oscillations in Precentral Cortices and Modulates with Movement and Speech.

Planning and executing motor behaviors requires coordinated neural activity among multiple cortical and subcortical regions of the brain. Phase-amplitude coupling between the high-gamma band amplitude and the phase of low frequency oscillations (theta, alpha, beta) has been proposed to reflect neural communication, as has synchronization of low-gamma oscillations. However, coupling between low-gamma and high-gamma bands has not been investigated. Here, we measured phase-amplitude coupling between low- and high-gamma in monkeys performing a reaching task and in humans either performing finger-flexion or word-reading tasks. We found significant coupling between low-gamma phase and high-gamma amplitude in multiple sensorimotor and premotor cortices of both species during all tasks. This coupling modulated with the onset of movement. These findings suggest that interactions between the low and high gamma bands are markers of network dynamics related to movement and speech generation.

The immune system and metabolic products in epilepsy and glioma-associated epilepsy: emerging therapeutic directions.

Epilepsy has a profound impact on quality of life. Despite the development of new antiseizure medications (ASMs), approximately one-third of affected patients have drug-refractory epilepsy and are nonresponsive to medical treatment. Nearly all currently approved ASMs target neuronal activity through ion channel modulation. Recent human and animal model studies have implicated new immunotherapeutic and metabolomic approaches that may benefit patients with epilepsy. In this Review, we detail the proinflammatory immune landscape of epilepsy and contrast this with the immunosuppressive microenvironment in patients with glioma-related epilepsy. In the tumor setting, excessive neuronal activity facilitates immunosuppression, thereby contributing to subsequent glioma progression. Metabolic modulation of the IDH1-mutant pathway provides a dual pathway for reversing immune suppression and dampening seizure activity. Elucidating the relationship between neurons and immunoreactivity is an area for the prioritization and development of the next era of ASMs.

Effect of surgical modification of deep brain stimulation lead trajectories on radiofrequency heating during MRI at 3T: from phantom experiments to clinical implementation.

OBJECTIVE: Radiofrequency (RF) tissue heating around deep brain stimulation (DBS) leads is a well-known safety risk during MRI, resulting in strict imaging guidelines and limited allowable protocols. The implanted lead's trajectory and orientation with respect to the MRI electric fields contribute to variations in the magnitude of RF heating across patients. Currently, there are no surgical requirements for implanting the extracranial portion of the DBS lead, resulting in substantial variations in clinical lead trajectories and consequently RF heating. Recent studies have shown that incorporating concentric loops in the extracranial lead trajectory can reduce RF heating. However, optimal positioning of the loops and the quantitative benefit of trajectory modification in terms of added safety margins during MRI remain unknown. In this study, the authors systematically evaluated the characteristics of DBS lead trajectories that minimize RF heating during 3T MRI to develop the best surgical practices for safe access to postoperative MRI, and they present the first surgical implementation of these modified trajectories. METHODS: The authors performed experiments to assess the maximum temperature increase of 244 distinct lead trajectories. They investigated the effect of the position, number, and size of the concentric loops on the skull. Experiments were performed in an anthropomorphic phantom implanted with a commercial DBS system, and RF exposure was generated by applying a high specific absorption rate sequence (B1+rms = 2.7 µT). The authors conducted test-retest experiments to assess the reliability of measurements. Additionally, they evaluated the effect of imaging landmarks and perturbations to the DBS device configuration on the efficacy of low-heating trajectories. Finally, two neurosurgeons implanted the recommended modified trajectories in patients, and the authors characterized their RF heating in comparison with unmodified trajectories. RESULTS: The maximum temperature increase ranged from 0.09°C to 7.34°C. The authors found that increasing the number of loops and positioning them closer to the surgical burr hole, particularly for the contralateral lead, substantially reduced RF heating. These trajectory modifications were easily incorporated during the surgical procedure and resulted in a threefold reduction in RF heating. CONCLUSIONS: Surgically modifying the extracranial portion of the DBS lead trajectory can substantially reduce RF heating during 3T MRI. The authors' results indicate that simple adjustments to the lead's configuration, such as small, concentric loops near the burr hole, can be readily adopted during DBS lead implantation to improve patient safety during MRI.

Medication only improves limb movements while deep brain stimulation improves eye and limb movements during visually-guided reaching in Parkinson's disease.

Background: Antiparkinson medication and subthalamic nucleus deep brain stimulation (STN-DBS), two common treatments of Parkinson's disease (PD), effectively improve skeletomotor movements. However, evidence suggests that these treatments may have differential effects on eye and limb movements, although both movement types are controlled through the parallel basal ganglia loops. Objective: Using a task that requires both eye and upper limb movements, we aimed to determine the effects of medication and STN-DBS on eye and upper limb movement performance. Methods: Participants performed a visually-guided reaching task. We collected eye and upper limb movement data from participants with PD who were tested both OFF and ON medication (n = 34) or both OFF and ON bilateral STN-DBS while OFF medication (n = 11). We also collected data from older adult healthy controls (n = 14). Results: We found that medication increased saccade latency, while having no effect on reach reaction time (RT). Medication significantly decreased saccade peak velocity, while increasing reach peak velocity. We also found that bilateral STN-DBS significantly decreased saccade latency while having no effect on reach RT, and increased saccade and reach peak velocity. Finally, we found that there was a positive relationship between saccade latency and reach RT, which was unaffected by either treatment. Conclusion: These findings show that medication worsens saccade performance and benefits reaching performance, while STN-DBS benefits both saccade and reaching performance. We explore what the differential beneficial and detrimental effects on eye and limb movements suggest about the potential physiological changes occurring due to treatment.

Variations in Determining Actual Orientations of Segmented Deep Brain Stimulation Leads Using the DiODe Algorithm: A Retrospective Study Across Different Lead Designs and Medical Institutions.

INTRODUCTION: Directional deep brain stimulation (DBS) leads have become widely used in the past decade. Understanding the asymmetric stimulation provided by directional leads requires precise knowledge of the exact orientation of the lead in respect to its anatomical target. Recently, the DiODe algorithm was developed to automatically determine the orientation angle of leads from the artifact on postoperative computed tomography (CT) images. However, manual DiODe results are user-dependent. This study analyzed the extent of lead rotation as well as the user agreement of DiODe calculations across the two most common DBS systems, namely, Boston Scientific's Vercise and Abbott's Infinity, and two independent medical institutions. METHODS: Data from 104 patients who underwent an anterior-facing unilateral/bilateral directional DBS implantation at either Northwestern Memorial Hospital (NMH) or Albany Medical Center (AMC) were retrospectively analyzed. Actual orientations of the implanted leads were independently calculated by three individual users using the DiODe algorithm in Lead-DBS and patients' postoperative CT images. The deviation from the intended orientation and user agreement were assessed. RESULTS: All leads significantly deviated from the intended 0° orientation (p < 0.001), regardless of DBS lead design (p < 0.05) or institution (p < 0.05). However, the Boston Scientific leads showed an implantation bias toward the left at both institutions (p = 0.014 at NMH, p = 0.029 at AMC). A difference of 10° between at least two users occurred in 28% (NMH) and 39% (AMC) of all Boston Scientific and 76% (NMH) and 53% (AMC) of all Abbott leads. CONCLUSION: Our results show that there is a significant lead rotation from the intended surgical orientation across both DBS systems and both medical institutions; however, a bias toward a single direction was only seen in the Boston Scientific leads. Additionally, these results raise questions into the user error that occurs when manually refining the orientation angles calculated with DiODe.

Management strategies for patients with neurologic stimulators during nonneurologic surgery: an update and review.

PURPOSE OF REVIEW: The goal of this review is to summarize the perioperative management of noncardiac implanted electrical devices (NCIEDs) and update the anesthesiologist on current recommendations for management when a NCIED is encountered during a nonneurosurgical procedure. RECENT FINDINGS: Indications for NCIEDs continue to expand, and increasing numbers of patients with NCIEDs are presenting for nonneurosurgical procedures. Recent case reports demonstrate that NCIEDs may meaningfully affect perioperative management including use of electrocautery and neuromonitoring. This review highlights the importance of evaluating NCIED function (including lead impedance) prior to surgery, provides an update on the MRI compatibility and safety of these devices, and reviews the management of patients with altered respiratory drive because of vagal nerve stimulators. SUMMARY: As the prevalence of NCIEDs in patients presenting for surgery increases, anesthesiologists will likely encounter these devices more frequently. To provide a well tolerated anesthetic, anesthesiologists should recognize the concerns associated with NCIEDs and how best to address them perioperatively.

Spinal cord stimulation-induced gastroparesis: A case report.

Background: Spinal cord stimulation (SCS) involves the utilization of an implantable neurostimulation device, stereotypically used in the treatment of patients with chronic neuropathic pain. While these devices have been shown to have significant clinical benefits, there have also been documented potential complications, including the risk of infection, fractured electrodes, electrode migration, and lack of symptom improvement. In addition, there has been minimal documentation on gastrointestinal (GI) side effects after SCS implantation. Case Description: A 42-year-old patient with chronic axial and radicular neuropathic pain in her back and left leg status post multiple lumbar surgeries underwent implantation of an open paddle lead in the T8-T9 region. After the procedure, the patient endorsed a 50% decrease in pain at the 6-week follow-up with no further concerns. However, at the 18 months follow-up, the patient endorsed severe constipation when the SCS was turned on, leading to subsequent evaluation by gastroenterology, motility studies, and a thorough bowel regimen. Symptoms persisted, and the patient ultimately opted for the removal of the SCS implant at 21 months after the initial surgery. Conclusion: While the exact mechanism behind the GI side effects endorsed in this patient is unknown, current literature postulates a variety of theories, including a SCS-induced parasympathetic blockade of the GI tract. Further, investigation is needed to determine the exact effects of SCS on the GI tract.

Pruritus and urticaria induced by neurostimulation: A case report and review of literature.

Background: Spinal cord stimulation (SCS) consists of the implantation of neuromodulatory devices in the spinal cord to treat refractory neuropathic pain. Although SCS technology has been proven of immense clinical benefit, complications remain including refractory pain, infection risk, and electrode migration or displacement. Till date, there are minimal reports of allergic side effects following SCS implantation. Case Description: In the first case, a 36-year-old male with chronic axial and radicular neuropathic pain in underwent implantation of an open paddle lead and generator. Within 1-3 h of activating the SCS, he developed diffuse raised erythematous hives. Over time, the SCS had immense clinical benefit for his pain reduction; however, he continued to experience recurrent hives and various other allergic reactions including facial flushing and photosensitivity. Four years later, he ultimately opted to retain the device for its clinical pain benefits. In the second case, a 35-year-old female with acute, intractable bilateral occipital neuralgia and a past medical history of Type 1 Chiari Malformation status-post-posterior fossa decompression underwent implantation of an occipital nerve stimulator (ONS). At 1-month follow-up, she began to experience pruritus across the back of her head and along the subcutaneous course of the lead. At 8 months, she continued to experience persistent symptoms, ultimately opting for device removal. Conclusion: Although allergic reactions to implanted neurostimulation systems are rare, and mechanisms not completely understood, existing studies posit multiple theories surrounding the pathophysiology of allergic reactions to these devices, such as delayed hypersensitivity reactions or contact dermatitis. Further research is needed to elucidate the cutaneous and immunologic side effects of SCS and ONS devices.

The Effects of Subthalamic Nucleus Deep Brain Stimulation and Retention Delay on Memory-Guided Reaching Performance in People with Parkinson's Disease.

BACKGROUND: Subthalamic nucleus deep brain stimulation (STN-DBS) improves intensive aspects of movement (velocity) in people with Parkinson's disease (PD) but impairs the more cognitively demanding coordinative aspects of movement (error). We extended these findings by evaluating STN-DBS induced changes in intensive and coordinative aspects of movement during a memory-guided reaching task with varying retention delays. OBJECTIVE: We evaluated the effect of STN-DBS on motor control during a memory-guided reaching task with short and long retention delays in participants with PD and compared performance to healthy controls (HC). METHODS: Eleven participants with PD completed the motor section of the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS III) and performed a memory-guided reaching task under four different STN-DBS conditions (DBS-OFF, DBS-RIGHT, DBS-LEFT, and DBS-BOTH) and two retention delays (0.5 s and 5 s). An additional 13 HC completed the memory-guided reaching task. RESULTS: Unilateral and bilateral STN-DBS improved the MDS-UPDRS III scores. In the memory-guided reaching task, both unilateral and bilateral STN-DBS increased the intensive aspects of movement (amplitude and velocity) in the direction toward HC but impaired coordinative aspects of movement (error) away from the HC. Furthermore, movement time was decreased but reaction time was unaffected by STN-DBS. Shorter retention delays increased amplitude and velocity, decreased movement times, and decreased error, but increased reaction times in the participants with PD. There were no interactions between STN-DBS condition and retention delay. CONCLUSION: STN-DBS may affect cognitive-motor functioning by altering activity throughout cortico-basal ganglia networks and the oscillatory activity subserving them.

Congress of Neurological Surgeons Systematic Review and Evidence-Based Guidelines for Occipital Nerve Stimulation for the Treatment of Patients With Medically Refractory Occipital Neuralgia: Update.

BACKGROUND: The Guidelines Task Force conducted a systematic review of the relevant literature on occipital nerve stimulation (ONS) for occipital neuralgia (ON) to update the original 2015 guidelines to ensure timeliness and accuracy for clinical practice. OBJECTIVE: To conduct a systematic review of the literature and update the evidence-based guidelines on ONS for ON. METHODS: The Guidelines Task Force conducted another systematic review of the relevant literature, using the same search terms and strategies used to search PubMed and Embase for relevant literature. The updated search included studies published between 1966 and January 2023. The same inclusion/exclusion criteria as the original guideline were also applied. Abstracts were reviewed, and relevant full text articles were retrieved and graded. Of 307 articles, 18 were retrieved for full-text review and analysis. Recommendations were updated according to new evidence yielded by this update . RESULTS: Nine studies were included in the original guideline, reporting the use of ONS as an effective treatment option for patients with medically refractory ON. An additional 6 studies were included in this update. All studies in the original guideline and this current update provide Class III evidence. CONCLUSION: Based on the availability of new literature, the current article is a minor update only that does not result in modification of the prior recommendations: Clinicians may use ONS as a treatment option for patients with medically refractory ON.