Epidemiological and Treatment Trends for Acute Ischemic Stroke Preceding and during the COVID-19 Pandemic.

BACKGROUND: The coronavirus disease 2019 (COVID-19) pandemic heralded a number of indirect perturbations to patient behavior and disease epidemiology, and mounting evidence suggests that the COVID-19 pandemic may have exacerbated underlying health disparities along racial and socioeconomic (SES) groups for acute ischemic stroke (AIS). We used 1 large national insurance database to identify whether patient demographics, disease severity, or mechanical thrombectomy (MT) rates changed for the treatment and management of AIS during COVID-19. METHODS: AIS patient records were queried from the Clinformatics® Data Mart Optum SES Database from the following 2 time periods: March 1, 2019-June 30, 2019 (pre-COVID-19), and March 1, 2020-June 30, 2020 (COVID-19). The database contains the longitudinal healthcare claims of approximately 77 million patients covered by a major insurance provider between 2003 and June 30, 2020 across all 50 states. Interrupted time-series analyses were used to assess trend differences before and after the COVID-19 pandemic. RESULTS: During the pre-COVID-19 period (March 1, 2019-June 30, 2019), there were 9,072 patients who presented for AIS, compared to 7,366 during COVID-19 (March 1, 2020-June 30, 2020). In both periods, the majority of patients were white (66.83% pre-COVID-19 and 67.91% during COVID-19). The average hospitalization duration was not different during the 2 time periods (p = 0.632), nor were rates of MT (p = 0.260). Total inpatient costs rose slightly for the COVID-19 period (USD 30,739 vs. USD 29,406; p = 0.015), and the median National Institutes of Health Stroke Scale (NIHSS) score was higher during CO-VID-19 (5 vs. 4; p = 0.023). When longitudinal trends were assessed for rates of MT and average NIHSS score for black and white patients, no differences were noted during the CO-VID-19 pandemic. Patients without any undergraduate experience did not present with AIS in increasing or decreasing incidence during COVID-19 (p = 0.268), but they did undergo declining rates of MT (p = 0.013). CONCLUSIONS: In the largest SES analysis of AIS patients during the COVID-19 era, we found that several SES factors, including race and income, did not seem to significantly impact utilization of MT for the treatment of AIS or the severity of the stroke at presentation.

The effect of socioeconomic status on age at diagnosis and overall survival in patients with intracranial meningioma.

BACKGROUND: Intracranial meningiomas are the most common primary tumors of the central nervous system. How socioeconomic status (SES) impacts treatment access and outcomes for brain tumor subtypes is an emerging area of research. Few studies have examined the relationship between SES and meningioma survival and management with reference to relevant clinical factors, including age at diagnosis. We studied the independent effects of SES on receiving surgery and survival probability in patients with intracranial meningioma. METHODS: 54,282 patients diagnosed with intracranial meningioma between 2003 and 2012 from the Surveillance, Epidemiology, and End Results (SEER) Program at the National Cancer Institute database were included. Patient SES was divided into tertiles. Patient age groups included 'older' (>65, the median patient age) and 'younger'. Multivariable linear regression and Cox proportional hazards model were used with SAS v9.4. Results were adjusted for race, sex, and tumor grade. Kaplan-Meier survival curves were constructed according to SES tertiles and age groups. RESULTS: Meningioma prevalence increased with higher SES tertile. Higher SES tertile was also associated with younger age at diagnosis (OR = 0.890, p < 0.05), an increased likelihood of undergoing gross total resection (GTR) (OR = 1.112, p < 0.05), and a trend toward greater 5-year survival probability (HR = 1.773, p = 0.0531). Survival probability correlated with younger age at diagnosis (HR = 2.597, p < 0.001), but not with GTR receipt. CONCLUSION: The findings from this national longitudinal study on patients with meningioma suggest that SES affects age at diagnosis and treatment access for intracranial meningiomas patients. Further studies are required to understand and address the mechanisms underlying these disparities.

Conventional versus stereotactic image guided pedicle screw placement during spinal deformity correction: a retrospective propensity score-matched study of a national longitudinal database.

PURPOSE/AIM: To compare complications, readmissions, revisions, and payments between navigated and conventional pedicle screw fixation for treatment of spine deformity. METHODS: The Thomson Reuters MarketScan national longitudinal database was used to identify patients undergoing osteotomy, posterior instrumentation, and fusion for treatment of spinal deformity with or without image-guided navigation between 2007-2016. Conventional and navigated groups were propensity-matched (1:1) to normalize differences between demographics, comorbidities, and surgical characteristics. Clinical outcomes and charges were compared between matched groups using bivariate analyses. RESULTS: A total of 4,604 patients were identified as having undergone deformity correction, of which 286 (6.2%) were navigated. Propensity-matching resulted in a total of 572 well-matched patients for subsequent analyses, of which half were navigated. Rate of mechanical instrumentation-related complications was found to be significantly lower for navigated procedures (p = 0.0371). Navigation was also associated with lower rates of 90-day unplanned readmissions (p = 0.0295), as well as 30- and 90-day postoperative revisions (30-day: p = 0.0304, 90-day: p = 0.0059). Hospital, physician, and total payments favored the conventional group for initial admission (p = 0.0481, 0.0001, 0.0019, respectively); however, when taking into account costs of readmissions, hospital payments became insignificantly different between the two groups. CONCLUSIONS: Procedures involving image-guided navigation resulted in decreased instrumentation-related complications, unplanned readmissions, and postoperative revisions, highlighting its potential utility for the treatment of spine deformity. Future advances in navigation technologies and methodologies can continue to improve clinical outcomes, decrease costs, and facilitate widespread adoption of navigation for deformity correction.

Postoperative outcomes following pediatric intracranial electrode monitoring: A case for stereoelectroencephalography (SEEG).

BACKGROUND: For patients with medically refractory epilepsy, intracranial electrode monitoring can help identify epileptogenic foci. Despite the increasing utilization of stereoelectroencephalography (SEEG), the relative risks or benefits associated with the technique when compared with the traditional subdural electrode monitoring (SDE) remain unclear, especially in the pediatric population. Our aim was to compare the outcomes of pediatric patients who received intracranial monitoring with SEEG or SDE (grids and strips). METHODS: We retrospectively studied 38 consecutive pediatric intracranial electrode monitoring cases performed at our institution from 2014 to 2017. Medical/surgical history and operative/postoperative records were reviewed. We also compared direct inpatient hospital costs associated with the two procedures. RESULTS: Stereoelectroencephalography and SDE cohorts both showed high likelihood of identifying epileptogenic zones (SEEG: 90.9%, SDE: 87.5%). Compared with SDE, SEEG patients had a significantly shorter operative time (118.7 versus 233.4 min, P < .001) and length of stay (6.2 versus 12.3 days, P < .001), including days spent in the intensive care unit (ICU; 1.4 versus 5.4 days, P < .001). Stereoelectroencephalography patients tended to report lower pain scores and used significantly less narcotic pain medications (54.2 versus 197.3 mg morphine equivalents, P = .005). No complications were observed. Stereoelectroencephalography and SDE cohorts had comparable inpatient hospital costs (P = .47). CONCLUSION: In comparison with subdural electrode placement, SEEG results in a similarly favorable clinical outcome, but with reduced operative time, decreased narcotic usage, and superior pain control without requiring significantly higher costs. The potential for an improved postoperative intracranial electrode monitoring experience makes SEEG especially suitable for pediatric patients.

Utilization of Novel High-Resolution, MRI-Based Vascular Imaging Modality for Preoperative Stereoelectroencephalography Planning in Children: A Technical Note.

INTRODUCTION: Stereoelectroencephalography (SEEG) is a powerful intracranial diagnostic tool that requires accurate imaging for proper electrode trajectory planning to ensure efficacy and maximize patient safety. Computed tomography (CT) angiography and digital subtraction angiography are commonly used, but recent developments in magnetic resonance angiography allow for high-resolution vascular visualization without added risks of radiation. We report on the accuracy of electrode placement under robotic assistance planning utilizing a novel high-resolution magnetic resonance imaging (MRI)-based imaging modality. METHODS: Sixteen pediatric patients between February 2014 and October 2017 underwent SEEG exploration for epileptogenic zone localization. A gadolinium-enhanced 3D T1-weighted spoiled gradient recalled echo sequence with minimum echo time and repetition time was applied for background parenchymal suppression and vascular enhancement. Electrode placement accuracy was determined by analyzing postoperative CT scans laid over preoperative virtual electrode trajectory paths. Entry point, target point, and closest vessel intersection were measured. RESULTS: For any intersection along the trajectory path, 57 intersected vessels were measured. The mean diameter of an intersected vessel was 1.0343 ± 0.1721 mm, and 21.05% of intersections involved superficial vessels. There were 157 overall intersection + near-miss events. The mean diameter for an involved vessel was 1.0236 ± 0.0928 mm, and superficial vessels were involved in 20.13%. Looking only at final electrode target, 3 intersection events were observed. The mean diameter of an intersected vessel was 1.0125 ± 0.2227 mm. For intersection + near-miss events, 24 were measured. An involved vessel's mean diameter was 1.1028 ± 0.2634 mm. For non-entry point intersections, 45 intersected vessels were measured. The mean diameter for intersected vessels was 0.9526 ± 0.0689 mm. For non-entry point intersections + near misses, 126 events were observed. The mean diameter for involved vessels was 0.9826 ± 0.1008 mm. CONCLUSION: We believe this novel sequence allows better identification of superficial and deeper subcortical vessels compared to conventional T1-weighted gadolinium-enhanced MRI.

Topical vancomycin for surgical prophylaxis in non-instrumented pediatric spinal surgeries.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: To determine if topical vancomycin irrigation reduces the incidence of post-operative surgical site infections following pediatric spinal procedures. Surgical site infections (SSIs) following spinal procedures performed in pediatric patients represent a serious complication. Prophylactic use of topical vancomycin prior to closure has been shown to be effective in reducing incidence of SSIs in adult spinal procedures. Non-instrumented cases make up the majority of spinal procedures in pediatric patients, and the efficacy of prophylactic topical vancomycin in these procedures has not previously been reported. METHODS: This retrospective study reviewed all non-instrumented spinal procedures performed over a period from 05/2014-12/2016 for topical vancomycin use, surgical site infections, and clinical variables associated with SSI. Topical vancomycin was utilized as infection prophylaxis, and applied as a liquid solution within the wound prior to closure. RESULTS: Ninety-five consecutive, non-instrumented, pediatric spinal surgeries were completed between 01/2015 and 12/2016, of which the last 68 utilized topical vancomycin. There was a 11.1% SSI rate in the non-topical vancomycin cohort versus 0% in the topical vancomycin cohort (P = 0.005). The number needed to treat was 9. There were no significant differences in risk factors for SSI between cohorts. There were no complications associated topical vancomycin use. CONCLUSIONS: Routine topical vancomycin administration during closure of non-instrumented spinal procedures can be a safe and effective tool for reducing SSIs in the pediatric neurosurgical population.

Cavernous malformations are rare sequelae of stereotactic radiosurgery for brain metastases.

The development of cavernous malformations many years following conventionally fractionated brain irradiation is well recognized and commonly reported. However, cavernous malformation induction following stereotactic radiosurgery (SRS) is largely unreported. Herein, we describe two cases of cavernous malformation formation years following SRS for brain metastases. A 20-year-old woman with breast cancer brain metastases received treatment with whole brain radiotherapy (WBRT), then salvage SRS 1.4 years later for progression of a previously treated metastasis. This lesion treated with SRS had hemorrhagic enlargement 3.0 years after SRS. Resection revealed a cavernous malformation. A 25-year-old woman had SRS for a brain metastasis from papillary thyroid carcinoma. Resection of a progressive, hemorrhagic lesion within the SRS field 2 years later revealed both recurrent carcinoma as well as cavernous malformation. As patients with brain metastases live longer following SRS, our cases highlight that the differential diagnosis of an enlarging enhancing lesion within a previous SRS field includes not only cerebral necrosis and tumor progression but also cavernous malformation induction.

Topical Vancomycin for Surgical Prophylaxis in Pediatric Craniofacial Surgeries.

Topical vancomycin has been demonstrated to be safe and effective for reducing surgical site infections (SSIs) following spine surgery in both adults and children, however, there are no studies of its efficacy in reducing SSIs in craniofacial surgery. The SSIs are one of the most common complications following craniofacial surgery. The complexity of craniofacial procedures, use of grafts and implants, long operative durations and larger surgical wounds all contribute to the heightened risk of SSIs in pediatric craniofacial cases. A retrospective review of all open and endoscopic pediatric craniofacial procedures performed between May 2014 and December 2017 at a single children's hospital was conducted to examine SSI rates between patients receiving topical vancomycin and a historical control group. The treatment group received topical vancomycin irrigation before wound closure. An ad-hoc cost analysis was performed to determine the cost-savings associated with topical vancomycin use. A total of 132 craniofacial procedures were performed during the study period, with 50 cases in the control group and 82 cases in the vancomycin group. Overall, SSI rate was 3.03%. Use of topical vancomycin irrigation led to a significant reduction in SSIs (4/50 SSI or 8.0% in control group vs 0/82 or 0% in vancomycin group, P = 0.04). No adverse events were observed with topical vancomycin use. The potential cost-savings associated with the use of topical vancomycin as SSI prophylaxis in this study was $102,152. Addition of topical vancomycin irrigation as routine surgical infection prophylaxis can be an effective and low-cost method for reducing SSI in pediatric craniofacial surgery.

Deep Brain Stimulation for Chronic Cluster Headache: A Review.

OBJECTIVES: Cluster headaches are a set of episodic and chronic pain syndromes that are sources of significant morbidity for patients. The standard of care for cluster headaches remains medication therapy, however a minority of patients will remain refractory to treatment despite changes to dosage and therapeutic combinations. In these patients, functional neuromodulation using Deep Brain Stimulation (DBS) presents the opportunity to alleviate the significant pain that is experienced by targeting the neurophysiological substrates that mediate pain. MATERIAL AND METHODS: We review the literature on chronic cluster headache, including the growing number of DBS case reports and series that describe the alleviation of pain in a majority of patients through conventional or endoventricular targeting of the posterior hypothalamus and ventral tegmental area, with a minimal side effect profile. RESULTS: In this review, the history and outcomes of DBS use for medication-refractory cluster headaches are examined, with discussion on future directions for improving this novel treatment modality and providing efficacious, longer-lasting pain relief in headache patients. CONCLUSION: In patients with chronic cluster headache, functional neuromodulation using DBS presents the opportunity to alleviate the significant pain that is experienced by targeting the neurophysiological substrates that mediate pain.

Nurse Telephonic Triage Service for After-hour Patient Calls in Neurosurgery.

OBJECTIVE: The aim of this study was to report the utilization and experience of the nurse telephonic triage service for after-hour patient calls in Neurosurgery. BACKGROUND: It is challenging for patients to reach their clinicians after-hours in a timely manner. This may result in worse health outcomes for the patients, or inappropriate utilization of emergency rooms and urgent care facilities. Physicians continue to remain overwhelmed with frequent after-hours calls in addition to other clinical responsibilities while on-call. METHODS: In August 2015, our institution launched the Clinical Advice Service (CAS) to provide a patient-centric, nurse-run telephone triage service for after-hour calls from Neurosurgery patients. Clinical protocols were created for use by CAS staff by Neurosurgery clinicians. RESULTS: Between July 2016 and June 2017, CAS has accepted 1021 after-hours calls from Neurosurgery patients. A total of 71.4% of these calls were clinical, and the remaining nonclinical (directions, appointments, general information). CAS escalated 37.3% of the calls to the on-call Neurosurgery physician; 4.8% Neurosurgery patients were triaged to the emergency room by CAS. CONCLUSION: CAS has been able to provide well-coordinated care to Neurosurgery patients while reducing physician workload.

The nucleus accumbens and alcoholism: a target for deep brain stimulation.

Alcohol use disorder (AUD) is a difficult to treat condition with a significant global public health and cost burden. The nucleus accumbens (NAc) has been implicated in AUD and identified as an ideal target for deep brain stimulation (DBS). There are promising preclinical animal studies of DBS for alcohol consumption as well as some initial human clinical studies that have shown some promise at reducing alcohol-related cravings and, in some instances, achieving long-term abstinence. In this review, the authors discuss the evidence and concepts supporting the role of the NAc in AUD, summarize the findings from published NAc DBS studies in animal models and humans, and consider the challenges and propose future directions for neuromodulation of the NAc for the treatment of AUD.

Outpatient spine surgery: defining the outcomes, value, and barriers to implementation.

Spine surgery is a key target for cost reduction within the United States health care system. One possible strategy involves the transition of inpatient surgeries to the ambulatory setting. Lumbar laminectomy with or without discectomy, lumbar fusion, anterior cervical discectomy and fusion, and cervical disc arthroplasty all represent promising candidates for outpatient surgeries in select populations. In this focused review, the authors clarify the different definitions used in studies describing outpatient spine surgery. They also discuss the body of evidence supporting each of these procedures and summarize the proposed cost savings. Finally, they examine several patient- and surgeon-specific considerations to highlight the barriers in translating outpatient spine surgery into actual practice.

Propensity-matched comparison of outcomes and cost after macroscopic and microscopic lumbar discectomy using a national longitudinal database.

OBJECTIVE There has been considerable debate about the utility of the operating microscope in lumbar discectomy and its effect on outcomes and cost. METHODS A commercially available longitudinal database was used to identify patients undergoing discectomy with or without use of a microscope between 2007 and 2015. Propensity matching was performed to normalize differences between demographics and comorbidities in the 2 cohorts. Outcomes, complications, and cost were subsequently analyzed using bivariate analysis. RESULTS A total of 42,025 patients were identified for the "macroscopic" group, while 11,172 patients were identified for the "microscopic" group. For the propensity-matched analysis, the 11,172 patients in the microscopic discectomy group were compared with a group of 22,340 matched patients who underwent macroscopic discectomy. There were no significant differences in postoperative complications between the groups other than a higher proportion of deep vein thrombosis (DVT) in the macroscopic discectomy cohort versus the microscopic discectomy group (0.4% vs 0.2%, matched OR 0.48 [95% CI 0.26-0.82], p = 0.0045). Length of stay was significantly longer in the macroscopic group compared to the microscopic group (mean 2.13 vs 1.83 days, p < 0.0001). Macroscopic discectomy patients had a higher rate of revision surgery when compared to microscopic discectomy patients (OR 0.92 [95% CI 0.84-1.00], p = 0.0366). Hospital charges were higher in the macroscopic discectomy group (mean $19,490 vs $14,921, p < 0.0001). CONCLUSIONS The present study suggests that the use of the operating microscope in lumbar discectomy is associated with decreased length of stay, lower DVT rate, lower reoperation rate, and decreased overall hospital costs.

Stereoelectroencephalography in children: a review.

Stereoelectroencephalography (SEEG) is an intracranial diagnostic measure that has grown in popularity in the United States as outcomes data have demonstrated its benefits and safety. The main uses of SEEG include 1) exploration of deep cortical/sulcal structures; 2) bilateral recordings; and 3) 3D mapping of epileptogenic zones. While SEEG has gradually been accepted for treatment in adults, there is less consensus on its utility in children. In this literature review, the authors seek to describe the current state of SEEG with a focus on the more recent technology-enabled surgical techniques and demonstrate its efficacy in the pediatric epilepsy population.

The effect of socioeconomic status on gross total resection, radiation therapy and overall survival in patients with gliomas.

Socioeconomic status (SES) is associated with survival in many cancers but the effect of socioeconomic status on survival and access to care for patients with gliomas has not been well studied. This study included 50,170 patients from the Surveillance, Epidemiology, and End Results Program at the National Cancer Institute database diagnosed with gliomas of the brain from 2003 to 2012. Patient SES was divided into tertiles and quintiles. Treatment options included radiation, surgery (gross total resection (GTR)/other surgery), and radiation with surgery. Multivariable logistic regression and Cox proportional hazards model were used to analyze data with SAS v9.4. The results were adjusted for age at diagnosis, race, sex, tumor type, and tumor grade. Kaplan-Meier survival curves were constructed according to SES tertiles and quintiles. Patients from a higher SES tertile were significantly more likely to receive surgery, radiation, GTR, and radiation with surgery (OR 1.092, 1.116, 1.103, 1.150 respectively, all p < 0.0001). This correlation was also true when patients were divided into quintiles (OR 1.054, 1.072, 1.062, 1.089 respectively, all p < 0.0001). Furthermore, the lowest SES tertiles (HR 1.258, 1.146) and the lowest SES quintiles (HR 1.301, 1.273, 1.194, 1.119) were associated with significantly shorter survival times (all p for trend <0.0001). Surgery, radiation therapy, surgery with radiation therapy, and GTR were also found to be associated with improved overall survival in glioma patients (HR 0.553, 0.849, 0.666, 0.491 respectively, all p < 0.0001). The findings from this national study suggest an effect of SES on access to treatment, and survival in patients with gliomas.

Stereotactic radiosurgery for non-vestibular cranial nerve schwanommas.

Non-vestibular cranial nerve schwannomas (NVCNS) are rare lesions, representing <10 % of cranial nerve schwannomas. The optimal treatment for NVCNS is often derived from vestibular schwannomas experience. Surgical resection has been referred to as the first line treatment for those benign tumors, but significant complication rates are reported. Stereotactic radiosurgery (SRS) has arisen as a mainstay of treatment for many benign tumors, including schwanommas. We retrospectively reviewed the outcomes of NVCNS treated by SRS to characterize tumor control, symptom relief, toxicity, and the role of hypo-fractionation of SRS dose. Eighty-eight (88) patients, with ninety-five (95) NVCNS were treated with either single or multi-session SRS from 2001 to 2014. Local control was achieved in 94 % of patients treated (median follow-up of 33 months, range 1-155). Complications were seen in 7.4 % of cases treated with SRS. At 1-year, 57 % of patients had improvement or resolution of their symptoms, while 35 % were stable and 8 % had worsening or increased symptoms. While 42 % received only one session, results on local control were similar for one or multiple sessions (p = 0.424). SRS for NVCNS is a treatment modality that provides excellent local control with minimal complication risk compared to traditional neurosurgical techniques. Tumor control obtained with a multi-session treatment was not significantly different from single session treatment. Safety profile was also comparable for uni or multi-session treatments. We concluded that, as seen in VS treated with CK SRS, radiosurgery treatment can be safely delivered in cases of NVCNS.

UTILITY OF A GLUCOCORTICOID SPARING STRATEGY IN THE MANAGEMENT OF PATIENTS FOLLOWING TRANSSPHENOIDAL SURGERY.

OBJECTIVE: Following transsphenoidal surgery (TSS), it is important to assess for and manage adrenal insufficiency (AI). The goal of this study is to assess the efficacy and safety of a glucocorticoid (GC) sparing protocol to limit GC exposure in patients undergoing TSS. METHODS: Adult patients undergoing TSS (excluding Cushing disease) with adequate adrenal function prior to surgery underwent TSS without perioperative GC coverage. Following TSS, daily morning fasting serum cortisol levels were tested. GCs were administered at stress doses for serum cortisol <5 mcg/dL, between 5 and 12 mcg/dL in the presence of clinically significant symptoms of AI, or >12 mcg/dL with severe headache, nausea or vomiting, fatigue, anorexia, or hyponatremia. The primary endpoint was the use of GCs in the immediate postoperative period. RESULTS: Of 178 subjects, GCs were administered to 80 (45%) patients for the following indications: 31.3% for serum cortisol <5 mcg/dL; 36.3% for cortisol between 5 and 12 mcg/dL accompanied by symptoms or signs of AI; 8.8% for moderate to severe postoperative hyponatremia; and 7.5% for severe headache, nausea and vomiting, fatigue, or anorexia with cortisol >12 mcg/dL. Logistic regression analysis showed that longer length of hospital stay (odds ratio [OR] 1.22, confidence interval [CI] 1.02-1.45) and the presence of new postoperative anterior pituitary hormone deficiency (OR 3.3, CI 1.26-8.67) were associated with postoperative GC use. By 12 weeks, only 14% of subjects remained on GCs. There were no adverse events related to withholding GCs. CONCLUSION: Our protocol for managing GC replacement is both safe and effective for limiting GC exposure in patients undergoing TSS. ABBREVIATIONS: AI = adrenal insufficiency CI = confidence interval FSH = follicle-stimulating hormone GC = glucocorticoid GH = growth hormone IGF-1 = insulin-like growth factor-1 IV = intravenous LH = luteinizing hormone LOS = length of hospital stay OR = odds ratio TSS = transsphenoidal surgery.

Clinical evaluation of concussion: the evolving role of oculomotor assessments.

Sports-related concussion is a change in brain function following a direct or an indirect force to the head, identified in awake individuals and accounting for a considerable proportion of mild traumatic brain injury. Although the neurological signs and symptoms of concussion can be subtle and transient, there can be persistent sequelae, such as impaired attention and balance, that make affected patients particularly vulnerable to further injury. Currently, there is no accepted definition or diagnostic criteria for concussion, and there is no single assessment that is accepted as capable of identifying all patients with concussion. In this paper, the authors review the available screening tools for concussion, with particular emphasis on the role of visual function testing. In particular, they discuss the oculomotor assessment tools that are being investigated in the setting of concussion screening.

Optogenetic modulation in stroke recovery.

Stroke is one of the leading contributors to morbidity, mortality, and health care costs in the United States. Although several preclinical strategies have shown promise in the laboratory, few have succeeded in the clinical setting. Optogenetics represents a promising molecular tool, which enables highly specific circuit-level neuromodulation. Here, the conceptual background and preclinical body of evidence for optogenetics are reviewed, and translational considerations in stroke recovery are discussed.