Radiotherapy versus combination radiotherapy-bevacizumab for the treatment of recurrent high-grade glioma: a systematic review.

BACKGROUND: High-grade gliomas (HGG) comprise the most common primary adult brain cancers and universally recur. Combination of re-irradiation therapy (reRT) and bevacizumab (BVZ) therapy for recurrent HGG is common, but its reported efficacy is mixed. OBJECTIVE: To assess clinical outcomes after reRT ± BVZ in recurrent HGG patients receiving stereotactic radiosurgery (SRS), hypofractionated radiosurgery (HFSRT), or fully fractionated radiotherapy (FFRT). METHODS: We performed a systematic review of PubMed, Web of Science, Scopus, Embase, and Cochrane databases, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We identified studies reporting outcomes for patients with recurrent HGG treated via reRT ± BVZ. Cohorts were stratified by BVZ treatment status and re-irradiation modality (SRS, HFSRT, and FFRT). Outcome variables were overall survival (OS), progression-free survival (PFS), and radiation necrosis (RN). RESULTS: Data on 1399 patients was analyzed, with 954 patients receiving reRT alone and 445 patients receiving reRT + BVZ. All patients initially underwent standard-of-care therapy for their primary HGG. In a multivariate analysis that adjusted for median patient age, WHO grade, RT dosing, reRT fractionation regimen, time between primary and re-irradiation, and re-irradiation target volume, BVZ therapy was associated with significantly improved OS (2.51, 95% CI [0.11, 4.92] months, P = .041) but no significant improvement in PFS (1.40, 95% CI [- 0.36, 3.18] months, P = .099). Patients receiving BVZ also had significantly lower rates of RN (2.2% vs 6.5%, P < .001). CONCLUSIONS: Combination of reRT + BVZ may improve OS and reduce RN rates in recurrent HGG, but further controlled studies are needed to confirm these effects.

Intratumor injection of CCL21-coupled vault nanoparticles is associated with reduction in tumor volume in an in vivo model of glioma.

PURPOSE: Glioblastoma (GBM) is the most common and malignant primary adult brain tumor. Current care includes surgical resection, radiation, and chemotherapy. Recent clinical trials for GBM have demonstrated extended survival using interventions such as tumor vaccines or tumor-treating fields. However, prognosis generally remains poor, with expected survival of 20 months after randomization. Chemokine-based immunotherapy utilizing CCL21 locally recruits lymphocytes and dendritic cells to enhance host antitumor response. Here, we report a preliminary study utilizing CPZ-vault nanoparticles as a vehicle to package, protect, and steadily deliver therapy to optimize CCL21 therapy in a murine flank model of GBM. METHODS: GL261 cells were subcutaneously injected into the left flank of eight-week-old female C57BL/6 mice. Mice were treated with intratumoral injections of either: (1) CCL21-packaged vault nanoparticles (CPZ-CCL21), (2) free recombinant CCL21 chemokine empty vault nanoparticles, (3) empty vault nanoparticles, or 4) PBS. RESULTS: The results of this study showed that CCL21-packaged vault nanoparticle injections can decrease the tumor volume in vivo. Additionally, this study showed mice injected with CCL21-packaged vault nanoparticle had the smallest average tumor volume and remained the only treatment group with a negative percent change in tumor volume. CONCLUSIONS: This preliminary study establishes vault nanoparticles as a feasible vehicle to increase drug delivery and immune response in a flank murine model of GBM. Future animal studies involving an intracranial orthotopic tumor model are required to fully evaluate the potential for CCL21-packaged vault nanoparticles as a strategy to bypass the blood brain barrier, enhance intracranial immune activity, and improve intracranial tumor control and survival.

Surgery versus stereotactic radiosurgery for the treatment of multiple meningiomas in neurofibromatosis type 2: illustrative case and systematic review.

Neurofibromatosis type 2 (NF2) is a genetic neoplastic disorder that presents with hallmark bilateral vestibular schwannomas and multiple meningiomas. Though the current standard of care for meningiomas includes surgery, the multiplicity of meningiomas in NF2 patients renders complete resection of all developing lesions infeasible. Stereotactic radiosurgery (SRS) may be a viable non-invasive therapeutic alternative to surgery. We describe a particularly challenging case in a 39-year-old male with over 120 lesions who underwent more than 30 surgical procedures, and review the literature. We also searched three popular databases and compared outcomes of SRS versus surgery for the treatment of multiple meningiomas in patients with NF2. A total of 50 patients (27 radiosurgical and 23 surgical) were identified. For patients treated with SRS, local tumor control was achieved in 22 patients (81.5%) and distal control was achieved in 14 patients (51.8%). No malignant inductions were observed at an average follow-up duration of 90 months. Complications in the SRS-treated cohort were reported in 9 patients (33%). Eight patients (29.6%) died due to disease progression. Six patients experienced treatment failure and required further management. For NF2 patients treated with surgery, 11 patients (48%) showed tumor recurrence and 10 patients (43.5%) died due to neurological complications. SRS may be a safe and effective alternative for NF2-associated meningiomas. Further studies are required to identify the ideal radiosurgical candidate.

Radiosurgery treatment is associated with improved facial nerve preservation versus repeat resection in recurrent vestibular schwannomas.

BACKGROUND: Vestibular schwannomas (VSs) are benign neoplasms of the Schwann cells of cranial nerve VIII, and treatment of VS typically involves surgical resection. However, tumor recurrence may necessitate reintervention, and secondary treatment modalities include repeat surgical resection or adjuvant radiosurgery. The purpose of this study is to examine the scientific literature in order to determine whether surgical resection or radiosurgery for recurrent VS results in better tumor control, hearing preservation, and preservation of facial nerve function. METHODS: The PubMed, Scopus, Embase, Cochrane, and Web of Science databases were searched for studies reporting on patients undergoing either radiosurgery or repeat surgical resection after primary surgical resection for recurrent VS. Statistical analyses were performed on the compiled data, primarily outcome data involving tumor control, hearing preservation, and preservation of facial nerve function. RESULTS: We analyzed the data of 15 individual studies involving 359 total patients, and our results reveal that tumor control rates are comparable between adjuvant radiosurgery (91%, CI: 88-94%) and secondary resection (92%, CI 75-98%). However, adjuvant radiosurgery was shown to preserve good facial nerve function better (94%, CI 84-98%) compared to secondary surgical resection (56%, CI 41-69%). CONCLUSION: With comparable tumor control rates and better preservation of good facial nerve function, this study suggests that secondary radiosurgery for recurrent VS is associated with both optimal tumor control and preservation of good facial nerve function.

Posterior Parietal Cortex Guides Visual Decisions in Rats.

Neurons in putative decision-making structures can reflect both sensory and decision signals, making their causal role in decisions unclear. Here, we tested whether rat posterior parietal cortex (PPC) is causal for processing visual sensory signals or instead for accumulating evidence for decision alternatives. We disrupted PPC activity optogenetically during decision making and compared effects on decisions guided by auditory versus visual evidence. Deficits were largely restricted to visual decisions. To further test for visual dominance in PPC, we evaluated electrophysiological responses after individual sensory events and observed much larger response modulation after visual stimuli than auditory stimuli. Finally, we measured trial-to-trial spike count variability during stimulus presentation and decision formation. Variability decreased sharply, suggesting that the network is stabilized by inputs, unlike what would be expected if sensory signals were locally accumulated. Our findings suggest that PPC plays a causal role in processing visual signals that are accumulated elsewhere.SIGNIFICANCE STATEMENT Defining the neural circuits that support decision making bridges a gap between our understanding of simple sensorimotor reflexes and our understanding of truly complex behavior. However, identifying brain areas that play a causal role in decision making has proved challenging. We tested the causal role of a candidate component of decision circuits, the rat posterior parietal cortex (PPC). Our interpretation of the data benefited from our use of animals trained to make decisions guided by either visual or auditory evidence. Our results suggest that PPC plays a causal role specifically in visual decision making and may support sensory aspects of the decision, such as interpreting the visual signals so that evidence for a decision can be accumulated elsewhere.

Neuroglial ectopia of the vestibular nerve masquerading as a vestibular schwannoma: A case report.

Neuroglial ectopia is a rare entity of undetermined clinical significance. Here, we report a unique case of neuroglial ectopia of the vestibular nerve. A 27-year-old pharmacy student with a previous radiological diagnosis of vestibular schwannoma presented to our clinic for surgical evaluation. Magnetic resonance imaging (MRI) of the brain revealed a 17-mm T1 hypo- to isointense, T2 iso- to hyperintense, poorly enhancing left cerebellopontine angle mass extending into the left internal auditory canal compatible by imaging with a vestibular schwannoma. The lesion was resected under MRI guidance. The frozen specimen came back as a benign hypocellular lesion. Histological assessment revealed a peripheral nerve engulfed by glial fibrillary acidic protein-positive, S-100-negative cells, suggestive of neuroglial ectopia. There was no evidence of schwannoma. The main concerns were benign neoplasm with potential for progression or sampling artifact. The patient had an uncomplicated hospital course. This case report demonstrates an unusual case of neuroglial ectopia of the vestibular nerve. The differential diagnoses for a poorly enhancing cerebellopontine angle mass should include neuroglial ectopia.

Middle cranial fossa approach for the repair of superior semicircular canal dehiscence is associated with greater symptom resolution compared to transmastoid approach.

BACKGROUND: Superior semicircular canal dehiscence (SSCD) is a disorder of the skull base that is gaining increasing recognition among neurosurgeons. Traditionally, the middle cranial fossa (MCF) approach has been used for the surgical repair of SSCD. However, the transmastoid (TM) approach is an alternative strategy that has demonstrated promising results. METHODS: We performed independent searches of a popular database to identify studies that described outcomes following the surgical repair of SSCD through MCF and TM approaches. The primary outcome was symptom resolution. RESULTS: Our analysis included 24 studies that described 230 patients that underwent either an MCF (n = 148, 64%) approach or a TM (n = 82, 36%) approach for primary surgical repair of SSCD. A greater percentage of patients in the MCF group experienced resolution of auditory symptoms (72% vs 59%, p = 0.012), aural fullness (83% vs 55%, p = 0.049), hearing loss (57% vs 31%, p = 0.026), and disequilibrium (75% vs 44%, p = 0.001) when compared to the TM group. The MCF approach was also associated with higher odds of symptom resolution for auditory symptoms (odds ratio [OR] 1.79, 95% confidence interval [CI] 1.14-2.82), aural fullness (OR 4.02, 95% CI 1.04-15.53), hearing loss (OR 2.91, 95% CI 1.14-7.42), and disequilibrium (OR 3.94, 95% CI 1.78-8.73). The mean follow-up was 9 months. CONCLUSIONS: The literature suggests that the MCF approach for the repair of SSCD is associated with greater symptom resolution when compared to the TM approach. This information could help facilitate patient discussions.

Multisensory decision-making in rats and humans.

We report a novel multisensory decision task designed to encourage subjects to combine information across both time and sensory modalities. We presented subjects, humans and rats, with multisensory event streams, consisting of a series of brief auditory and/or visual events. Subjects made judgments about whether the event rate of these streams was high or low. We have three main findings. First, we report that subjects can combine multisensory information over time to improve judgments about whether a fluctuating rate is high or low. Importantly, the improvement we observed was frequently close to, or better than, the statistically optimal prediction. Second, we found that subjects showed a clear multisensory enhancement both when the inputs in each modality were redundant and when they provided independent evidence about the rate. This latter finding suggests a model where event rates are estimated separately for each modality and fused at a later stage. Finally, because a similar multisensory enhancement was observed in both humans and rats, we conclude that the ability to optimally exploit sequentially presented multisensory information is not restricted to a particular species.

Dynamic weighting of multisensory stimuli shapes decision-making in rats and humans.

Stimuli that animals encounter in the natural world are frequently time-varying and activate multiple sensory systems together. Such stimuli pose a major challenge for the brain: Successful multisensory integration requires subjects to estimate the reliability of each modality and use these estimates to weight each signal appropriately. Here, we examined whether humans and rats can estimate the reliability of time-varying multisensory stimuli when stimulus reliability changes unpredictably from trial to trial. Using an existing multisensory decision task that features time-varying audiovisual stimuli, we independently manipulated the signal-to-noise ratios of each modality and measured subjects' decisions on single- and multi-sensory trials. We report three main findings: (a) Sensory reliability influences how subjects weight multisensory evidence even for time-varying, stochastic stimuli. (b) The ability to exploit sensory reliability extends beyond human and nonhuman primates: Rodents and humans both weight incoming sensory information in a reliability-dependent manner. (c) Regardless of sensory reliability, most subjects are disinclined to make "snap judgments" and instead base decisions on evidence presented over the majority of the trial duration. Rare departures from this trend highlight the importance of using time-varying stimuli that permit this analysis. Taken together, these results suggest that the brain's ability to use stimulus reliability to guide decision-making likely relies on computations that are conserved across species and operate over a wide range of stimulus conditions.

Age and the power of zero CAC in cardiac risk assessment: overview of the literature and a cautionary case.

The coronary artery calcium (CAC) score is a marker of advanced coronary atherosclerosis. Numerous prospective cohorts have validated CAC as an independent marker that improves prognostication in atherosclerotic cardiovascular disease (ASCVD) beyond traditional risk factors. Accordingly, CAC is now incorporated into international cardiovascular guidelines as a tool to inform medical decision-making. Particular interest concerns the significance of zero CAC score (CAC=0). While many studies report CAC=0 to virtually exclude obstructive coronary artery disease (CAD), non-negligible rates of obstructive CAD despite CAC=0 are reported in certain populations. Overall, the current literature supports the power of zero CAC as a strong downward risk classifier in older patients, whose CAD burden predominantly involves calcified plaque. However, with their higher burden of non-calcified plaque, CAC=0 does not reliably exclude obstructive CAD in patients under 40 years. Illustrating this point, we present a cautionary case of a 31-year-old patient found to have severe two-vessel CAD despite CAC=0. We highlight the value of coronary computed tomography angiography (CCTA) as the gold-standard non-invasive imaging modality when the diagnosis of obstructive CAD is in question.

Customized polyetheretherketone (PEEK) implants are associated with similar hospital length of stay compared to autologous bone used in cranioplasty procedures.

OBJECTIVE: Cranioplasty is the surgical repair of cranial defects. Throughout its history, a number of different materials have been used, however, there is still no consensus on which material or method is best. The purpose of this study was to analyze the viability of polyetheretherketone (PEEK) cranioplasty to autologous cranioplasty modalities. METHODS: A single-institution retrospective analysis of patients undergoing cranioplasties was performed. Patients were divided to PEEK and autologous cranioplasty cohorts. Parameters of interest included patient demographics and perioperative outcomes. A p-value <0.05 was considered statistically significant. RESULTS: A total of 66 patients met the inclusion criteria (PEEK: 22, autologous: 44). There were 36 males (54.5%) and 30 females (45.5%). Mean age of the entire cohort was 51.7 years (range 19-85 years). Baseline demographics were similar in both cohorts as measured by the modified frailty index (mFI) (p = 0.67). Univariate analysis revealed a significantly longer hospital length of stay (LoS) associated with the autologous group (p = 0.02). However, multivariate analysis did not yield such an association (p = 0.06) after controlling for mFI. Although the individual postoperative complication rates were similar between the two cohorts, autologous cranioplasty was associated with a significantly higher rate of total postoperative complications (65.9% vs 36.4%, p = 0.02). CONCLUSION: Overall, PEEK biomaterials may offer a superior complication profile with similar hospital LoS compared to autologous bone implants used in cranioplasty. Future studies are warranted to validate our findings and further evaluate the utility of PEEK in cranioplasty.

Stereotactic Radiosurgery for Glomus Jugulare Tumors: Systematic Review and Meta-Analysis.

BACKGROUND: Glomus jugulare tumors (GJTs) are benign paragangliomas of the jugular foramen. Traditional management of these tumors involves surgical resection; however, considering the proximity of these tumors to important neurovasculature, stereotactic radiosurgery (SRS) may be an appropriate noninvasive treatment to consider. The aim of this meta-analysis was to evaluate SRS as a treatment option for GJTs. METHODS: An online search using PubMed, Web of Science, Scopus, and Cochrane databases was performed in March 2019 for articles on radiosurgery treatment of GJTs. The screening process followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. RESULTS: The final analysis comprised 23 studies including 460 patients. Average rates of tinnitus, hearing loss, and lower cranial nerve deficit as presenting symptoms were 56% (95% confidence interval [CI], 46%-66%), 56% (95% CI, 44%-68%), and 42% (95% CI, 31%-54%), respectively. Overall clinical status improvement rate after treatment was 47% (95% CI, 37%-57%). Rates of tinnitus, hearing loss, and lower cranial nerve improvement after treatment were 54% (95% CI, 44%-63%), 28% (95% CI, 19%-40%), and 22% (95% CI, 11%-39%), respectively. The mean follow-up time across studies was 47 months (range, 4-268 months). The aggregate tumor control rate at the time of follow-up was 95% (95% CI, 93%-97%). CONCLUSIONS: The tumor control rate of 95% and 47% symptomatic improvement suggest that SRS may be a suitable treatment modality for these hypervascular skull base tumors. Future studies are warranted to further evaluate the potential role of SRS in management of GJTs.

A Comparison of Spinal Robotic Systems and Pedicle Screw Accuracy Rates: Review of Literature and Meta-Analysis.

Introduction The motivation to improve accuracy and reduce complication rates in spinal surgery has driven great advancements in robotic surgical systems, with the primary difference between the newer generation and older generation models being the presence of an optical camera and multijointed arm. This study compares accuracy and complication rates of pedicle screw placement in older versus newer generation robotic systems reported in the literature. Methods We performed a systemic review and meta-analysis describing outcomes of pedicle screw placement with robotic spine surgery. We assessed the robustness of these findings by quantifying levels of cross-study heterogeneity and publication bias. Finally, we performed meta-regression to test for associations between pedicle screw accuracy and older versus newer generation robotic spine system usage. Results Average pedicle screw placement accuracy rates for old and new generation robotic platforms were 97 and 99%, respectively. Use of new generation robots was significantly associated with improved pedicle screw placement accuracy ( p = 0.03). Conclusion Accuracy of pedicle screw placement was high across all generations of robotic surgical systems. However, newer generation robots were shown to be significantly associated with accurate pedicle screw placement, showing the benefits of upgrading robotic systems with a real-time optical camera and multijointed arm.

Supraorbital Keyhole Craniotomy for Clipping Cerebral Aneurysms: A Systematic Review and Meta-Analysis.

BACKGROUND: Open cerebrovascular surgery remains an irreplaceable tool in the neurosurgeon's armamentarium for cerebral aneurysms. Among open approaches, the supraorbital keyhole approach provides a novel approach with less soft tissue dissection and cortical exposure compared with the traditional pterional approach. OBJECTIVE: To perform a descriptive synthesis of the literature on cerebral aneurysms approached surgically via the supraorbital keyhole approach. METHODS: Following PRISMA guidelines, we performed a systematic literature review of PubMed, Scopus, and Web of Science. Patient demographic data, aneurysm characteristics, Hunt and Hess score, clipping rate, operative time, postoperative neurologic status, length of stay, and follow-up were extracted. We then performed a meta-analysis to obtain pooled estimates of these metrics across studies, including assessments for cross-study heterogeneity and publication bias. RESULTS: Under a random-effects estimate, mean intraoperative rupture rate was 6.0%. Clipping rate was 99% under a pooled fixed estimate. Significant publication bias was found within studies for aneurysm clipping rate. Forest plot analysis showed an average clinical outcome of 93% of a modified Rankin Scale score from 0 to 2 or Glasgow Outcome Scale score of IV or V at postoperative follow-up. CONCLUSIONS: Aneurysm treatment is highly heterogeneous within the literature. The supraorbital keyhole approach is an effective strategy for aneurysm treatment.

Aortic Arch Calcification in Ungated Lung Computed Tomography Scans as Predictors of Atherosclerotic Cardiovascular Disease: Methodology and Reproducibility in a Multi-Ethnic Study of Atherosclerosis.

Background: Aortic arch calcium (AAC), which is frequently detected on ungated lung computed tomography (CT) due to a large field of view, can serve as a marker of subclinical atherosclerotic burden. Our study sought to validate novel cardiac screening metrics of subclinical atherosclerosis by evaluating the inter- and intra-observer reproducibility of AAC measurements with ungated lung CT. Methods: The authors randomly selected 100 ungated lung CT scans from the Multi-Ethnic Study of Atherosclerosis cohort. A Bland-Altman plot analysis was used to test inter- and intra-reader reproducibility, after measuring the total arch calcium score and arch calcium volume. Results: The intra-reader reproducibility for the total arch calcium score and arch calcium volume in all subjects was excellent at 99% and 97%, respectively. The inter-reader reproducibility for the total arch calcium score and volume in all subjects was similarly excellent at 97% and 96%, respectively. Conclusions: The high reproducibility of ungated lung CT suggests a potential new method of stratifying the atherosclerotic cardiovascular disease risk among patients undergoing lung CT without requiring additional scanning. This methodology helps promote routine reporting of AAC and coronary artery calcium based on millions of ungated CT images acquired for lung screening purposes.

Superior Semicircular Canal Dehiscence Revision Surgery Outcomes: A Single Institution's Experience.

BACKGROUND: Superior semicircular canal dehiscence (SSCD) is an abnormality of the otic capsule, which normally overlies the superior semicircular canal. Surgical management is indicated in patients with persistent and debilitating symptoms. Given the complexity of the disease, there are patients who experience less favorable surgical outcomes and require revision surgery. The purpose of this study was to report to the rate of postoperative symptomatic improvement in patients who required revision surgery. METHODS: A retrospective analysis of patients undergoing SSCD surgical repair at a single institution was performed. Information on patient demographics, primary and secondary surgical approaches, surgical outcomes, and follow-up length was collected. RESULTS: Seventeen patients underwent 20 revision surgeries. There were eleven (65%) females and six (35%) males. Mean age of the cohorts was 50 years (range 30-68 years), and mean follow-up length was 6.8 months (range 0.1-31.1 months). Cerebrospinal fluid leak was noted in 67% of cases. The greatest postoperative symptomatic resolution was reported in oscillopsia (100%), headache (100%), and internal sound amplification (71%), while the least postoperative symptomatic resolution was reported in tinnitus (42%), aural fullness (40%), and dizziness (29%). CONCLUSIONS: Revision surgery can provide symptomatic improvement in select SSCD patients; however, patients should be cautioned about the possibility of less favorable outcomes than in index surgery. Revision surgeries are associated with a considerably higher rate of perioperative cerebrospinal fluid leak.

Analysis of academic publishing output among 1634 successful applicants in the 2011-2018 neurosurgery residency match.

BACKGROUND: Research productivity is a key criterion for applicant selection reported by residency program directors. Research volume reported on neurosurgery residency applications has risen steadily over the past decade. OBJECTIVE: Perform retrospective bibliographic searches of successful applicants who matched into U.S. neurosurgery residency programs from 2011 to 2018, and assess the relationship between academic publishing and residency placement. METHODS: Gender, MD/PhD status, U.S. News research ranking of medical school, and international medical graduate status (IMG) were determined for 1634 successful applicants from 2011 to 2018. Indexed publications before and after the start of residency were tabulated by Scopus®. Publication counts were stratified by first author, basic/clinical science, case reports, reviews, or other research. We then compared publishing trends across demographic variables and match cohorts. RESULTS: Average pre-residency publications increased from 2.6 [1.7, 3.4] in 2011 to 6.5 [5.1, 7.9] in 2018. Men, PhD-holders, Top 20 and Top 40 U.S. medical school graduates, and IMGs had higher pre-residency publication counts overall. After stratifying by match cohort, however, there was no significant effect of gender on pre-residency publications. Applicants matching into residency programs with highly ranked affiliated hospitals had significantly higher pre-residency publications. CONCLUSION: Publishing volume of successful neurosurgery applicants in the U.S. has risen recently and is associated with the stature of matched residency programs. Given the gap between verifiable and claimed research on residency applications, attention is needed to objectively evaluate research credentials in the selection process. The impending phase out of USMLE step 1 scores may increase emphasis on academic productivity.

Neuroanatomical characteristics and speech perception in noise in older adults.

OBJECTIVES: Previous research has attributed older adults' difficulty with perceiving speech in noise to peripheral hearing loss. However, recent studies have suggested a more complex picture and implicate the central nervous system in sensation and sensory deficits. This study examines the relationship between the neuroanatomical structure of cognitive brain regions and the ability to perceive speech in noise in older adults. In particular, the neuroanatomical characteristics of the left ventral and dorsal prefrontal cortex (PFC) are considered relative to standard measures of hearing in noise. DESIGN: The participants were 15 older and 14 younger right-handed native speakers of American English who had no neurologic deficits and scored better than normal on standardized cognitive tests. We measured the participants' peripheral hearing ability and their ability to perceive speech in noise using established tests. Anatomical magnetic resonance images were taken and analyzed to extract regional volumes and thicknesses of several key neuroanatomical structures. RESULTS: Younger adults had better hearing sensitivity and better speech perception in noise ability than older adults. For the older adults only, the volume of the left pars triangularis and the cortical thickness of the left superior frontal gyrus were significant predictors of performance on the speech in noise test. DISCUSSION: These findings suggest that, in addition to peripheral structures, the central nervous system also contributes to the ability to perceive speech in noise. In older adults, a decline in the relative volume and cortical thickness of the PFC during aging can therefore be a factor in a declining ability to perceive speech in a naturalistic environment. These findings are consistent with the decline-compensation hypothesis, which states that a decline in sensory processing caused by cognitive aging can be accompanied by an increase in the recruitment of more general cognitive areas as a means of compensation. We found that a larger PFC volume may compensate for declining peripheral hearing. Clinically, recognizing the contribution of the cerebral cortex expands treatment possibilities for hearing loss in older adults beyond peripheral hearing aids to include strategies for improving cognitive function. We conclude by considering several mechanisms by which the PFC may facilitate speech perception in noise, including inhibitory control, attention, cross-modal compensation, word prediction and phonological working memory, although no definitive conclusion can be drawn.

Cerebral vessel anatomy as a predictor of first-pass effect in mechanical thrombectomy for emergent large-vessel occlusion.

OBJECTIVE: Mechanical thrombectomy is effective in acute ischemic stroke secondary to emergent large-vessel occlusion, but optimal efficacy is contingent on fast and complete recanalization. First-pass recanalization does not occur in the majority of patients. The authors undertook this study to determine if anatomical parameters of the intracranial vessels impact the likelihood of first-pass complete recanalization. METHODS: The authors retrospectively evaluated data obtained in 230 patients who underwent mechanical thrombectomy for acute ischemic stroke secondary to large-vessel occlusion at their institution from 2016 to 2018. Eighty-six patients were identified as having pure M1 occlusions, and 76 were included in the final analysis. The authors recorded and measured clinical and anatomical parameters and evaluated their relationships to the first-pass effect. RESULTS: The first-pass effect was achieved in 46% of the patients. When a single device was employed, aspiration thrombectomy was more effective than stent retriever thrombectomy. A larger M1 diameter (p = 0.001), decreased vessel diameter tapering between the petrous segment of the internal carotid artery (ICA) and M1 (p < 0.001), and distal collateral grading (p = 0.044) were associated with first-pass recanalization. LASSO (least absolute shrinkage and selection operator) was used to generate a predictive model for recanalization using anatomical variables. CONCLUSIONS: The authors demonstrated that a larger M1 vessel diameter, low rate of vessel diameter tapering along the course of the intracranial ICA, and distal collateral status are associated with first-pass recanalization for patients with M1 occlusions.

Postoperative Hearing Preservation in Patients Undergoing Retrosigmoid Craniotomy for Resection of Vestibular Schwannomas: A Systematic Review of 2034 Patients.

BACKGROUND: Vestibular schwannomas (VS) are benign tumors derived from Schwann cells ensheathing the vestibulocochlear nerve. The retrosigmoid (RS) surgical approach is useful to resect tumors of multiple sizes while affording the possibility of preserving postoperative hearing. OBJECTIVE: To conduct a systematic review of published literature investigating hearing preservation rates in patients who underwent the RS approach for VS treatment. METHODS: The PubMed, Scopus, and Embase databases were surveyed for studies that reported preoperative and postoperative hearing grades on VS patients who underwent RS treatment. Hearing preservation rates were calculated, and additional patient demographic data were extracted. Tumor size data were stratified to compare hearing preservation rates after surgery for intracanalicular, small (0-20 mm), and large (>20 mm) tumors. RESULTS: Of 383 deduplicated articles, 26 studies (6.8%) met eligibility criteria for a total of 2034 patients with serviceable preoperative hearing, for whom postoperative hearing status was evaluated. Aggregate hearing preservation was 31% and 35% under a fixed and random effects model, respectively. A mixed effects model was used to determine hearing preservation rates depending on tumor size, which were determined to be 57%, 37%, and 12% for intracanalicular, small, and large tumors, respectively. Significant cross-study heterogeneity was found (I2 = 93%, τ2 = .964, P < .01; Q = 287.80, P = < .001), with rates of hearing preservation ranging from 0% to 100%. CONCLUSION: Tumor size may have an effect on hearing preservation rates, but multiple factors should be considered. Discussion of a patient's expectations for hearing preservation is critical when deciding on VS treatment plans.