Eloquent Brain Research Articles

Awake surgery for isolated parenchymal degenerating neurocysticercosis – Case report and focused review of misdiagnosis of neurocysticercosis

Differential diagnosis of isolated single neurocysticercosis can be difficult, and management is controversial. We report here an original surgical strategy, and review previous studies reporting misdiagnosis, using the PRISMA guidelines. A 24-year-old man was admitted to our hospital for recent memory impairment, hypoesthesia of the right hand, and recurrent focal seizures without loss of consciousness. Brain MRI revealed a single ring-enhancing parenchymal lesion in the left superior postcentral gyrus, with large perilesional edema. Since exhaustive systemic exploration was negative, surgical resection of the lesion was decided on in a multidisciplinary team meeting. To preserve eloquent brain areas, surgery was performed in awake condition. It allowed complete resolution of clinical manifestations. The diagnosis of neurocysticercosis was confirmed on pathology. This case illustrates the utility of awake surgery in degenerating neurocysticercosis in functional areas, and emphasizes the importance of including it in differential diagnosis of cystic ring-enhancing brain lesions.

A brief history of cortical functional localization and its relevance to neurosurgery.

Modern cortical mapping is a cornerstone for safe supratentorial glioma resection in eloquent brain and allows maximal resection with improved functional outcomes. The unlocking of brain functionality through close observation and eventually via cortical stimulation has a fascinating history and was made possible by contributions from early physician-philosophers and neurosurgery's founding fathers. Without an understanding of brain function and functional localization, none of today's modern cortical mapping would be possible.

Does eloquence subtype influence outcome following arteriovenous malformation surgery?

Although numerous arteriovenous malformation (AVM) grading scales consider eloquence in risk assessment, none differentiate the types of eloquence. The purpose of this study was to determine if eloquence subtype affects clinical outcome. This is a retrospective review of a prospectively collected clinical database of brain AVMs treated with microsurgery in the period from 1997 to 2017. The only inclusion criterion for this study was the presence of eloquence as defined by the Spetzler-Martin grading scale. Eloquence was preoperatively categorized by radiologists. Poor outcome was defined as a modified Rankin Scale (mRS) score 3-6, and worsening clinical status was defined as an increase in the mRS score at follow-up. Logistic regression analyses were performed. Two hundred forty-one patients (49.4% female; average age 33.9 years) with eloquent brain AVMs were included in this review. Of the AVMs (average size 2.7 cm), 54.4% presented with hemorrhage, 46.2% had deep venous drainage, and 17.0% were diffuse. The most common eloquence type was sensorimotor (46.1%), followed by visual (27.0%) and language (22.0%). Treatments included microsurgery alone (32.8%), microsurgery plus embolization (51.9%), microsurgery plus radiosurgery (7.9%), and all three modalities (7.5%). Motor mapping was used in 9% of sensorimotor AVM cases, and awake speech mapping was used in 13.2% of AVMs with language eloquence. Complications occurred in 24 patients (10%). At the last follow-up (average 24 months), 71.4% of the patients were unchanged or improved and 16.6% had a poor outcome. There was no statistically significant difference in the baseline patient and AVM characteristics among the different subtypes of eloquence. In a multivariate analysis, in comparison to visual eloquence, both sensorimotor (OR 7.4, p = 0.004) and language (OR 6.5, p = 0.015) eloquence were associated with poor outcomes. Additionally, older age (OR 1.31, p = 0.016) and larger AVM size (OR 1.37, p = 0.034) were associated with poor outcomes. Unlike visual eloquence, sensorimotor and language eloquence were associated with worse clinical outcomes after the resection of eloquent AVMs. This nuance in AVM eloquence demands consideration before deciding on microsurgical intervention, especially when numerical grading systems produce a score near the borderline between operative and nonoperative management.

Transcortical insular glioma resection: clinical outcome and predictors.

Insular lobe gliomas continue to challenge neurosurgeons due to their complex anatomical position. Transcortical and transsylvian corridors remain the primary approaches for reaching the insula, but the adoption of one technique over the other remains controversial. The authors analyzed the transcortical approach of resecting insular gliomas in the context of patient tumor location based on the Berger-Sinai classification, achievable extents of resection (EORs), overall survival (OS), and postsurgical neurological outcome. The authors studied 255 consecutive cases of insular gliomas that underwent transcortical tumor resection in their division. Tumor molecular pathology, location, EOR, postoperative neurological outcome for each insular zone, and the accompanying OS were incorporated into the analysis to determine the value of this surgical approach. Lower-grade insular gliomas (LGGs) were more prevalent (63.14%). Regarding location, giant tumors (involving all insular zones) were most prevalent (58.82%) followed by zone I+IV (anterior) tumors (20.39%). In LGGs, tumor location was an independent predictor of survival (p = 0.003), with giant tumors demonstrating shortest patient survival (p = 0.003). Isocitrate dehydrogenase 1 (IDH1) mutation was more likely to be associated with giant tumors (p < 0.001) than focal tumors located in a regional zone. EOR correlated with survival in both LGG (p = 0.001) and higher-grade glioma (HGG) patients (p = 0.008). The highest EORs were achieved in anterior-zone LGGs (p = 0.024). In terms of developing postoperative neurological deficits, patients with giant tumors were more susceptible (p = 0.038). Postoperative transient neurological deficit was recorded in 12.79%, and permanent deficit in 15.70% of patients. Patients who developed either transient or permanent postsurgical neurological deficits exhibited poorer survival (p < 0.001). The transcortical surgical approach can achieve maximal tumor resection in all insular zones. In addition, the incorporation of adjunct technologies such as multimodal brain imaging and mapping of cortical and subcortical eloquent brain regions into the transcortical approach favors postoperative neurological outcomes, and prolongs patient survival.

Translational Brain Mapping at the University of Rochester Medical Center: Preserving the Mind Through Personalized Brain Mapping.

The Translational Brain Mapping Program at the University of Rochester is an interdisciplinary effort that integrates cognitive science, neurophysiology, neuroanesthesia, and neurosurgery. Patients who have tumors or epileptogenic tissue in eloquent brain areas are studied preoperatively with functional and structural MRI, and intraoperatively with direct electrical stimulation mapping. Post-operative neural and cognitive outcome measures fuel basic science studies about the factors that mediate good versus poor outcome after surgery, and how brain mapping can be further optimized to ensure the best outcome for future patients. In this article, we describe the interdisciplinary workflow that allows our team to meet the synergistic goals of optimizing patient outcome and advancing scientific understanding of the human brain.

Supramarginal resection of glioblastoma: 5-ALA fluorescence, combined intraoperative strategies and correlation with survival.

Glioblastoma treatment requires a multidisciplinary approach involving oncologists, radiotherapists and surgeons. Surgery constitutes the initial step of the therapeutic strategy and its efficacy is dependent on the extent of resection (EOR). Over the last decade, the goal of surgical treatment was the resection of the contrast enhancement on T1 MRI, defined as gross-total resection (GTR). More recently, an increasing number of studies reports a positive impact on survival parameters of a more aggressive surgical strategy aiming to resect all peri-tumoral infiltrated areas. These areas are histologically characterized by the presence of pathological cells infiltrating normal white matter and surround the neoplastic core of glioblastoma identified by gadolinium enhancement in T1-weighted MR. Intuitively, the major risk of the so called supramarginal resection is related to the possibility of resecting functionally eloquent brain tissue. Several strategies have been proposed to maximize the safety of resection and minimize the occurrence of postoperative functional deficits. The aim of this review was to focus on the clinical impact of supramarginal resection of glioblastomas, highlighting the role of image-guided surgery combined with neuromonitoring to increase surgical safety and efficacy. The MEDLINE database has been queried for the literature research. Ten studies matched the inclusion criteria, reporting a global number of 3221 patients. The current evidence suggests a positive correlation between a more extensive resection based on FLAIR abnormal areas and overall survival.

Parasagittal and parafalcine meningiomas: integral strategy for optimizing safety and retrospective review of a single surgeon series

Background: Parafalcine and parasagittal meningiomas present unique challenges for resection. Although maximal safe resection is the primary goal of surgical management for these lesions, venous infarction and eloquent cortical structure damage occur in up to 14% of cases. Therefore, optimal preoperative planning and intraoperative technique is critical.Methods: We retrospectively reviewed a single surgeon’s case series with resection of 58 parafalcine and parasagittal meningiomas. Operative strategy included not crossing the superior sagittal sinus (SSS) during craniotomy, not resecting the falx, use of motor evoked potentials (MEPs) to avoid damage to eloquent brain, and selective use of preoperative embolization.Results: Fifty-eight patients, 45 with parasagittal meningiomas and 13 with parafalcine meningiomas were evaluated. Median age 58.34 years and mean follow-up was 7.7 months. Gross total resection (GTR) was achieved in 51.7% of patients and near-gross total resection rate was 48.3%. Postoperative day one discharge rate was 62.1%. Complication rate was 8.6%, with new postoperative neurologic deficit rate of 5.2%. Tumor recurrence/growth documented on postoperative imaging rate was 3.4%.Conclusions: In our series of parasagittal and parafalcine meningioma resection, we report a 51.7% GTR rate associated with a low complication rate. Techniques to minimize perioperative morbidity include not crossing the SSS on craniotomy, avoiding falx resection, using MEPs, and selective preoperative embolization to optimize the chance of a maximal safe resection. We utilize a strategy of conservative initial tumor resection focused on maximizing the chances of a favorable neurologic outcome, followed as necessary by adjuvant therapies such as radiosurgery and salvage therapies such as laser interstitial thermal therapy, although longer follow-up comparable to that of series with more radical approaches is required to determine if long term outcomes are comparable.

Keyhole, Trans-Sylvian, Trans-Sulcal Resection of an Insular Cerebral Cavernous Malformation: 2-Dimensional Operative Video.

Microsurgical resection of deep-seated cerebral cavernous malformations may result in a high rate of temporary and a lower, but nonetheless significant, rate of permanent disability. Use of trans-sulcal corridors may allow the surgeon to gain access to select deep-seated lesions without injury. Informed consent was obtained from this patient for a minimally invasive trans-sulcal approach to the malformation. This video illustrates the use of a trans-Sylvian, trans-sulcal approach to resect a deep insular/basal ganglia cavernous malformation in a young patient. The use of the neuronavigation is essential for success in these types of operation as this tool limits the surgeon's footprint in eloquent brain. Unlike superficial lesions where the removal of hemosiderin stained brain is possible and often safe, resection of deep-seated lesions requires the surgeon to distinguish between hemosiderin-stained brain and residual cavernous malformation. This task is not simple, and residual cavernous malformation is the most common reason for re-bleed in patients who have undergone surgery. Resection of symptomatic cavernous malformations in deep locations can be performed safely, but outcomes are heavily influenced by proper patient selection and surgeon experience. In patients with multiple cerebral cavernous malformations, such as the one in this case, genetic testing should be performed.

102 Late-onset paradoxical reactions in neurotuberculosis presenting 18 months and 20 years after treatment

IntroductionParadoxical reactions (PRs) during treatment of neurotuberculosis are common but late-onset PRs after completion of anti-tuberculous treatment are reported very rarely. The management of late-onset PRs is challenging as excluding other diagnoses is difficult without invasive testing.MethodsTwo cases of late-onset PRs after treatment for neurotuberculosis are reported. The timing of onset, clinical and radiological features of these PRs are described and the diagnostic work up and outcomes after empiric immunosuppression reviewed.ResultsA 24-year-old woman presented with right-sided focal motor seizures 18 months after receiving anti-tuberculous treatment for neurotuberculosis. MRI showed enlargement of a previous left frontal tuberculoma with extensive oedema. A biopsy was not performed as the lesion involved eloquent brain and the patient declined a lumbar puncture. She was treated empirically with corticosteroids for six months and had clinical and radiological improvement.A 56-year-old woman presented with left leg weakness and numbness 20 years after treatment for multiple cerebral tuberculomas. MRI showed a new confluent area of T2 hyperintensity in the right frontal and parietal lobes. Cerebrospinal fluid was negative for acid-fast bacilli. She was treated with corticosteroids for 2 months with progressive improvement.ConclusionsLate onset PRs to neurotuberculosis can occur months to years after completing anti-tuberculous therapy. Recognising this entity is important so unnecessary treatments and brain biopsy may be avoided. Empiric immunosuppression with corticosteroids appears to be safe if early follow up and repeat imaging is arranged.

Modern Treatment of Brain Arteriovenous Malformations Using Preoperative Planning Based on Navigated Transcranial Magnetic Stimulation: A Revisitation of the Concept of Eloquence

Navigated transcranial magnetic stimulation (nTMS) provides a reliable identification of "eloquent" cortical brain areas. Moreover, it can be used for diffusion tensor imaging fiber tracking of eloquent subcortical tracts. We describe the use of nTMS-based cortical mapping and diffusion tensor imaging fiber tracking for defining the "eloquence" of areas surrounding brain arteriovenous malformations (BAVMs), aiming to improve patient stratification and treatment. We collected data of BAVMs suspected to be in eloquent areas treated between 2017 and 2019, and submitted to nTMS-based reconstruction of motor, language, and visual pathways for the definition of the eloquence of the surrounding brain areas. We describe the nTMS-based approach and analyze its impact on patient stratification and allocation to treatment in comparison with the standard assessment of eloquence based on anatomical landmarks. Ten patients were included in the study. Preliminarily, 9 BAVMs were suspected to be located in an eloquent area. After nTMS-based mapping, only 5 BAVMs were confirmed to be close to eloquent structures, thus leading to a change of the score for eloquence and of the final BAVMs grading in 60% of patients. Treatment was customized according to nTMS information, and no cases of neurological worsening were observed. Radiological obliteration was complete in 7 cases microsurgically treated, and accounted for about 70% in the remaining 3 patients 1 year after radiosurgical treatment. The nTMS-based information allows an accurate stratification and allocation of patients with BAVMs to the most effective treatment according to a modern, customized, neurophysiological identification of the adjacent eloquent brain networks.

Awake Throughout Craniotomy: Initial Experience and the Anaesthetic Challenges

The tumor of brain near or within the eloquent brain regions like motor and language cortex requires excision of tumor and at the same time preservation of the functional area. To achieve the second goal the awake craniotomy is being practiced where the aim is to make the patient awake during resection of tumor so that the motor and speech function can be constantly monitored. We present the anaesthetic management of a case of craniotomy for low grade oligodendroma in frontal region with the awake throughout technique.

Electroencephalography in Epilepsy Evaluation.

Epilepsy is a heterogeneous disorder that is often associated with abnormal electroencephalogram (EEG) findings. This article provides an overview of common EEG findings in epileptic disorders. The physiologic basis of EEG and intracranial EEG studies is also discussed. EEG is widely used in clinical practice. Because of the paroxysmal nature of seizure disorders, interictal epileptiform discharges, such as spikes and sharp waves, are often used to support the diagnosis of epilepsy when a habitual seizure is not captured by EEG. Interictal and ictal EEG findings also underlie the classification of seizures and epilepsy. Continuous critical care EEG monitoring has become an invaluable study in the diagnosis and treatment of subclinical seizures and nonconvulsive status epilepticus. Intracranial EEG with subdural or intraparenchymal electrodes is warranted when localization of the seizure focus and mapping of eloquent brain areas are required to plan epilepsy surgery. The EEG is a key tool in the diagnosis of epilepsy. Interictal and ictal EEG findings are crucial for the confirmation and classification of seizure disorders. Intracranial EEG monitoring is also indispensable for planning surgery for some patients.

Surgical resection of cavernous angioma located within eloquent brain areas: International survey of the practical management among 19 specialized centers

PurposeThe practical management of cavernous angioma located within eloquent brain area before, during and after surgical resection is poorly documented. We assessed the practical pre-operative, intra-operative, and post-operative management of cavernous angioma located within eloquent brain area. MethodAn online survey composed of 61 items was sent to 26 centers to establish a multicenter international retrospective cohort of adult patients who underwent a surgical resection as the first-line treatment of a supratentorial cavernous angioma located within or close to eloquent brain area. Results272 patients from 19 centers (mean 13.6 ± 16.7 per center) from eight countries were included. The pre-operative management varied significantly between centers and countries regarding the pre-operative functional assessment, the pre-operative epileptological assessment, the first given antiepileptic drug, and the time to surgery. The intra-operative environment varied significantly between centers and countries regarding the use of imaging systems, the use of functional mapping with direct electrostimulations, the extent of resection of the hemosiderin rim, the realization of a post-operative functional assessment, and the time to post-operative functional assessment. The present survey found a post-operative improvement, as compared to pre-operative evaluations, of the functional status, the ability to work, and the seizure control. ConclusionsWe observed a variety of practice between centers and countries regarding the management of cavernous angioma located within eloquent regions. Multicentric prospective studies are required to solve relevant questions regarding the management of cavernous angioma-related seizures, the timing of surgery, and the optimal extent of hemosiderin rim resection.

Awake craniotomies for epileptic gliomas: intraoperative and postoperative seizure control and prognostic factors.

Awake craniotomy is well-established for tumors resected in eloquent brain areas. Whether awake craniotomy provides improved seizure control in patients with epileptic gliomas has not been well evaluated. This study analyzed the incidence, risk factors and outcome of seizures during and following awake craniotomies for patients presenting with epilepsy and glioma. Forty-one patients undergoing awake craniotomies for epileptic gliomas were retrospectively analyzed. Postoperative seizure was defined as either early (postoperative day 7 + before) or late onset (after postoperative day 7). Neurologic function was assessed with modified Rankin Scales (mRS) and seizure outcome was assessed using International League Against Epilepsy (ILAE) classification. Multivariable logistic regression was used for clinical variables associated with postoperative seizures. Three patients (7.3%) had intraoperative seizures however did not fail the awake craniotomies. Mean mRS before and after the awake craniotomies were 2.4 and 2.1, respectively (P = 0.032). Fourteen (34.1%) patients had early seizures, which caused longer hospitalization than those without early seizures (P = 0.03). Surgical resection to isocitrate dehydrogenase 1 (IDH1) mutation tumors, comparing to IDH1 wild type tumors, caused better postoperative seizure control. 6-month late seizure freedom was achieved in 33 patients (80.5%). Early seizure recurrence (odds ratio = 30.75; P = 0.039) and postoperative mRS ≥ 3 (odds ratio = 7.00; P = 0.047) were independent risk factors for late seizures. Intraoperative seizures could be well-controlled during awake craniotomies. Early postoperative seizures extended hospitalization and strongly predicted late seizure recurrence. Awake craniotomies benefited long-term seizure control in patients with epileptic gliomas.

Visualization of Brain Shift Corrected Functional Magnetic Resonance Imaging Data for Intraoperative Brain Mapping

BackgroundBrain tumor surgery requires careful balance between maximizing tumor excision and preserving eloquent cortex. In some cases, the surgeon may opt to perform an awake craniotomy including intraoperative mapping of brain function by direct cortical stimulation (DCS) to assist in surgical decision-making. Preoperatively, functional magnetic resonance imaging (fMRI) facilitates planning by identification of eloquent brain areas, helping to guide DCS and other aspects of the surgical plan. However, brain deformation (shift) limits the usefulness of preoperative fMRI during surgery. To address this, an integrated visualization method for fMRI and DCS results is developed that is intuitive for the surgeon.MethodsAn image registration pipeline was constructed to display preoperative fMRI data corrected for brain shift overlaid on images of the exposed cortical surface at the beginning and completion of DCS mapping. Preoperative fMRI and DCS data were registered for a range of misalignments, and the residual registration errors were calculated. The pipeline was validated on imaging data from five brain tumor patients who underwent awake craniotomy.ResultsRegistration errors were well under 5 mm (the approximate spatial resolution of DCS) for misalignments of up to 25 mm and approximately 10–15°. For rotational misalignments up to 20°, the success rate was 95% for an error tolerance of 5 mm. Failures were negligible for rotational misalignments up to 10°. Good quality registrations were observed for all five patients.ConclusionsA proof-of-concept image registration pipeline is presented with acceptable accuracy for intraoperative use, providing multimodality visualization with potential benefits for intraoperative brain mapping.

Resting-State Functional Connectivity in Neurosurgical Patients Under Propofol Anesthesia: Detectability and Variability Between Patients and Between Sessions

Intraoperative assessment of functional connectivity (FC) provides a new possibility for mapping the eloquent brain region before, during, and after tumor resection. The aim of this study was to perform a systematic analysis of detectability of FC and its variation between subjects and sessions. FC was analyzed in 10 patients with pituitary adenoma under propofol anesthesia before and after tumor resection. FC of each session (20 sessions total) was correlated to a reference matrix of a group of healthy subjects to evaluate variations of overall, interhemispheric, and intrahemispheric FC between sessions. Resting-state patterns could be detected during anesthesia (F1,9= 112.14, P < 0.001). There was a significant effect of session (F1,9= 19.401, P= 0.002), which included a reduction in resting state from the first to second session. There was no effect of connection type (F2,8= 1.498, P= 0.280), and there was no interaction between connection type and session (F2,8= 0.187, P=0.833). The correlation between the observed reduction in resting-state activity between the sessions and the time span between sessions was not significant (r= 0.25, P= 0.29). FC of the first session showed a significant correlation to the initial dose of anesthesia (r= 0.7, P=0.007). However, there was no significant correlation between the total dose of propofol and FC of the second session (r= 1.7, P= 0.6). Significant FC could be detected under anesthesia but showed a significant decrease in the second session. To implement FC intraoperative brain mapping, further studies are required to optimize the depth sedation to obtain stable FC between sessions.

Modified unilateral approach for mid-third giant bifalcine meningiomas: resection using an oblique surgical trajectory and falx window.

Utilizing the shortest available trajectory is the norm for excision of meningiomas. However, such an approach for the mid-third/central falcine meningiomas risks the adjoining draining veins and eloquent cortex. A larger size and bilaterality of such tumors adds to the surgical challenge. Herein, we report the surgical nuances of a modified unilateral approach in patients operated for giant bilateral symmetrical mid-third falcine meningiomas. Five such patients were operated. The clinico-radiologic data was studied at presentation and at the follow-up. The meningiomas were subclassified into those that were located in the anterior and posterior half of the central falx, and their surgical trajectory was chosen accordingly. The tumor was excised through an oblique anterior or a posterior trajectory instead of directly working over the major draining veins and eloquent brain. The falx was incised to create a surgical window and access the tumor on the contralateral side. Four patients had meningiomas in the anterior half and one in the posterior half of central falx. Simpson excision was grade II in four patients. One patient showed small residual tumor and underwent stereotactic radiosurgery. The overall mean follow-up of the patients was 9.2months. All the patients had good clinical outcome. Giant bifalcine meningiomas can be safely resected through a unilateral approach. Falx opening serves as a window to remove the tumor from the contralateral side. An oblique trajectory rather than an end-on access to these tumors minimizes the risk of venous and cortical injury.

First United Kingdom Experience of Navigated Transcranial Magnetic Stimulation in Preoperative Mapping of Brain Tumors

Surgery for lesions in eloquent brain areas remains challenging owing to the risk of permanent neurological deficits. To date, direct electrical stimulation (DES) and intraoperative neuromonitoring represent the reference standard. Recently, navigated transcranial magnetic stimulation (nTMS) has emerged as a mapping tool to optimize surgical planning. Our aim was to correlate nTMS with the intraoperative findings and assess its effects on surgical decision-making. We retrospectively reviewed our series of patients who had undergone craniotomy for removal of a brain tumor at our institution with preoperative nTMS, intraoperative neuromonitoring, and DES from February 2017 to February 2018. Demographic data, tumor entity and location, extent of resection, change in surgical approach, and neurological outcome were collected. Of 35 patients, 24 (68.6%) had undergone preoperative motor mapping and 11 (31.4%) had undergone mapping for language. Histopathological examination demonstrated glioma in 88.6% (high grade, n= 24; low grade, n= 6), metastasis (n= 2), epidermoid cyst (n= 1), and cavernoma (n= 1). nTMS resulted in change in the surgical strategy in 31.5% (craniotomy size, n= 7; access pathway, n= 3; surgical indication, n= 1). The specificity of nTMS for language was 66.7%, with a negative predictive value of 74.1%. nTMS motor mapping correlated with DES in all cases, with a mean abductor pollicis brevis hotspot distance of 3.50 ± 0.66 mm (n= 9). nTMS is a safe, noninvasive adjunctive tool for preoperative mapping of brain tumors in eloquent areas. Furthermore, nTMS can influence the surgical decisions in up to one third of patients in our experience.

Closed-Loop Brain Stimulation for Drug-Resistant Epilepsy: Towards an Evidence-Based Approach to Personalized Medicine.

Closed-loop brain stimulation is one of the few treatments available for patients who are ineligible for traditional surgical resection of the epileptogenic zone, due to having generalized epilepsy, multifocal epilepsy, or focal epilepsy localized to an eloquent brain region. Due to its clinical efficacy and potential to delivery personalized therapy based on an individual's own intracerebral electrophysiology, this treatment is becoming an important part of clinical practice, despite a limited understanding of how to program detection and stimulation parameters for optimal, patient-specific benefit. To bring this challenge into focus, we review the evolution of neural stimulation for epilepsy, provide a technical overview of the RNS System (the only FDA-approved closed-loop device), and discuss the major challenges of working with a closed-loop device. We then propose an evidence-based solution for individualizing therapy that is driven by a bottom-up informatics approach.

Value of magnetic resonance imaging in predicting BRAF mutation in craniopharyngiomas

Craniopharyngiomas, according to the World Health Organization (WHO) definition, are benign, partially cystic epithelial tumors of the sellar region, presumably derived from Rathke pouch epithelium and designated as grade I lesion of the central nervous system. They have been described as histologically benign tumors that behaves in a malignant manner. This “malignancy” is due to the vicinity to highly eloquent brain structures, its unpredictable biologic behavior, and its high local recurrence rates.