Baseline ImPACT Composite Scores in Student-Athletes With Attention-Deficit/Hyperactivity Disorder

BACKGROUND

Athletes who are diagnosed with attention-deficit/hyperactivity disorder (ADHD) are at increased risk of concussion compared to other athletes. Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) is a widely used concussion tool, but it relies on pre-injury baseline testing that can be affected by psychiatric conditions. This research aims to determine if there are differences in pre-injury testing composite scores in student-athletes with ADHD compared to those without ADHD diagnosis.

METHODS

We obtained 11,563 pre-season ImPACT assessments of 7,454 student-athletes (ages: 12-22) from 2009 to 2019. After exclusions, there were 6,920 control and 276 ADHD subjects. Multivariable linear regression analyses compared the independent effect of ADHD on the six ImPACT composite score metrics with Bonferroni correction for multiple comparisons with a = 0.008.

RESULTS

Univariate analyses indicated ADHD is associated with more symptoms as measured by the Post-Concussion Symptom Scale (PCSS) (β = 2.67, 95% CI: 1.47-3.87, p < .0001) and worse Impulse Control scores (β = 0.93, 95% CI: 0.33-1.53, p = .002). In multivariate analysis, this association was the same for symptom score (β = 2.48, 95% CI: 1.22-3.74, p < .0001), but Impulse Control was not significantly different after multiple comparison adjustment (β = 0.87, 95% CI: 0.22-1.15, p = .009).

CONCLUSIONS

The ADHD subjects reported worse symptoms at baseline and had worse Impulse Control in univariate analysis, but not multivariate analysis. These results can further guide clinicians in concussion diagnosis and test interpretations for student-athletes with ADHD, considering the symptom burden at baseline.

The effect of age on baseline neurocognitive performance

OBJECTIVE

Evaluate the independent effect of age on baseline neurocognitive performance.

STUDY DESIGN

Baseline ImPACT scores from tests taken by 7454 athletes aged 12-22 from 2009 to 2019 were split into three age cohorts: 12-14 years (3244), 15-17 years (3732), and 18-22 years (477). Linear regression analyses were used to evaluate the effect of age on ImPACT composite scores while controlling for demographic differences, medication-use, and symptom burden. Significance values have been set at p < 0.05.

RESULTS

Linear regression analyses demonstrated that increased age does not significantly affect symptom score (β = 0.06, p = 0.54) but does improve impulse control (β = -0.45, p < 0.0001), verbal memory (β = 0.23, p = 0.03), visualmotor (β = 0.77, p < 0.0001), and reaction time (β = -0.008, p < 0.0001) scores.  However, age did not have an effect on visual memory scores (β = -0.25, p = 0.07).

CONCLUSIONS

Age was shown to be an independent modifier of impulse control, verbal memory, visual motor, and reaction time scores but not visual memory or symptom scores.  This underscores the previous literature showing developmental differences as age increases among the adolescent athlete population.  This data also indicates the need for repeat neurocognitive baseline testing every other year as baseline scoring is likely to change as athletes become older.

Bibliometric Analysis of International Medical Graduates and Professorship Promotion in Neurosurgery

BACKGROUND

International medical graduates (IMGs) comprise ∼25% of physicians in the United States. Differences in promotion rates from assistant to associate to full professorship based on medical school location have been understudied. We aim to stratify odds of professional advancement by 3 categories: IMG with U.S. residency, IMG with international residency, and U.S. medical with U.S. residency training.

METHODS

We created and queried a database after exclusions of 1334 neurosurgeons including multiple demographic factors: academic productivity and promotion rates. Stratified logistic regression modeled odds of promotion including the variables: decades out of training, Scopus h-index, gender, and training location. Odds ratios (ORs) and 95% confidence intervals (CIs) for each variable were calculated.

RESULTS

Significant predictors of increased associate versus assistant professorship included decades out of training (OR = 2.519 [95% CI: 2.07-3.093], P < 0.0001) and Scopus h-index (OR = 1.085 [95% CI: 1.064-1.108], P < 0.0001) while international medical school with U.S. residency (OR = 0.471 [95% CI: 0.231-0.914], P = 0.0352) was associated with decreased promotion. Significant predictors of associate versus full professorship were decades out of training (OR = 2.781 [95% CI: 2.268-3.444], P < 0.0001) and Scopus h-index (OR = 1.064 [95% CI: 1.049-1.080], P < 0.0001). Attending medical school or residency internationally was not associated with odds of full professorship.

CONCLUSIONS

Time out of residency and Scopus h-index were associated with higher academic rank regardless of career level. Attending medical school internationally with U.S. residency was associated with lower odds of associate professorship promotion over 10 years. There was no relationship between IMG and full professorship promotion. IMGs who attended residency internationally did not have lower promotion rates. These findings suggest it may be harder for IMGs to earn promotion from assistant to associate professor in neurosurgery.

The Effect of Multiple Scopus Profiles on the Perceived Academic Productivity of Neurosurgeons in the United States

OBJECTIVE

Bibliometrics assessing academic productivity plays a significant role in neurosurgeons' career advancement. This study aimed to evaluate the influence of multiple author profiles on Scopus on neurosurgeon author-level metrics (h-index, document number, citation number).

METHODS

A list of 1671 academic neurosurgeons was compiled through public searches of hospital and faculty websites for 115 neurosurgical residency training programs. The h-index, document number, and citation number for each neurosurgeon were collected using the Scopus algorithm. For surgeons with multiple profiles, total document number and citation number were calculated by summing results of each profile. Cumulative h-indices were calculated manually. Comparisons were made between surgeons with a single Scopus profile and surgeons with multiple profiles.

RESULTS

A total of 124 neurosurgeons with multiple profiles were identified. Gender distribution (P = 0.47), years in practice (P = 0.06), subspecialty (P = 0.32), and academic rank (P = 0.16) between neurosurgeons with a single profile versus multiple profiles were similar. Primary profile h-index median was 16 (interquartile range [IQR]: 8-34), combined profiles median was 20 (IQR: 11-36), and percent loss median was 17.3% (IQR: 3%-33%) (P < 0.001). For document number, primary profile median was 46 (IQR: 16-127), combined profiles median was 55 (IQR: 22-148), and percent loss median was 16.2% (IQR: 7%-36%) (P < 0.001). For citation number, primary profile median was 1030 (IQR: 333-4082), combined profiles median was 1319 (IQR: 546-4439), and percent loss median was 14.1% (IQR: 4%-32%) (P < 0.001).

CONCLUSIONS

U.S. academic neurosurgeons with multiple existing profiles on Scopus experience a 17.3% loss in h-index, a 16.2% loss in document number, and a 14.1% loss in citations, heavily undercounting their perceived academic productivity.

Novel Grading Scales for Static and Flexion-Extension Magnetic Resonance Imaging in Patients with Cervical Spondylotic Myelopathy

BACKGROUND

Flexion-extension magnetic resonance imaging (MRI) has potential to identify cervical pathology not detectable on conventional static MRI. Our study evaluated standard quantitative and novel subjective grading scales for assessing the severity of cervical spondylotic myelopathy in dynamic sagittal MRI as well as in static axial and sagittal images.

METHODS

Forty-five patients underwent both conventional and flexion-extension MRI prior to anterior cervical discectomy and fusion from C4 through C7. In addition to measuring Cobb angles and cervical canal diameter, grading scales were developed for assessment of vertebral body translation, loss of disc height, change in disc contour, deformation of cord contour, and cord edema. Data were collected at all levels from C2-C3 through C7-T1. Variations in measurements between cervical levels and from flexion through neutral to extension were assessed using Mann-Whitney, Kruskal-Wallis, and two-way ANOVA tests.

RESULTS

Cervical canal diameter, vertebral translation, and posterior disc opening changed significantly from flexion to neutral to extension positions (P < 0.01). When comparing operative versus nonoperative cervical levels, significant differences were found when measuring sagittal cervical canal dimensions, vertebral translation, and posterior disc opening (P < 0.01). Degenerative loss of disc height, disc dehydration, deformation of ventral cord contour, and cord edema were all significantly increased at operative levels versus nonoperative levels (P < 0.01).

CONCLUSIONS

Flexion-extension MRI demonstrated significant changes not available from conventional MRI. Subjective scales for assessing degenerative changes were significantly more severe at levels with operative cervical spondylotic myelopathy. The utility of these scales for planning surgical intervention at specific and adjacent levels is currently under investigation.

Seasonal Effects on Postoperative Complications After Spinal Surgery: A National Database Analysis

OBJECTIVE

To investigate the role of seasonality on postoperative complications after spinal surgery.

METHODS

Data were obtained from the American College of Surgeons National Surgical Quality Improvement Program database from 2011 to 2018. Current Procedural Terminology codes were used to identify the following procedures: posterior cervical decompression and fusion, cervical laminoplasty, posterior lumbar fusion, lumbar laminectomy, and spinal deformity surgery. The database was queried for deep vein thrombosis (DVT), pulmonary embolism, pneumonia, sepsis, septic shock, Clostridium difficile infection, stroke, cardiac arrest, myocardial infarction, urinary tract infection (UTI), and early unplanned hospital readmission (readmission). Warm season was defined as April-September, whereas cold season was defined as October-March. Statistical analysis included computing overall complication rates and comparison between seasons using univariate analysis and multivariable logistic regression.

RESULTS

A total of 208,291 individuals underwent spinal surgery from 2011 to 2018. There was a statistically significant increase in UTI (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.07-1.26; P = 0.0002) and readmission (OR, 1.06; 95% CI, 1.02-1.11, P = 0.007) in the warm season compared with the cold season. An investigation into the July effect showed increases in DVT (OR, 1.24; 95% CI, 1.03-1.48; P = 0.020) and thromboembolic events (OR 1.17; 95% CI, 1.01-1.35; P = 0.032) in July-September compared with the preceding 3 months.

CONCLUSIONS

The results showed a higher incidence of UTI and readmission among spine surgery patients in the warm season and a higher incidence of DVT and thromboembolic events from July to September. In both cases, the effect of seasonality is statistically significant, but the absolute difference is small and may not suggest policy changes.

Evaluation of differences across age groups in the incidence, severity, and recovery of concussion in adolescent student-athletes from 2009 to 2019

OBJECTIVE

Concussion incidence is known to be highest in children and adolescents; however, there is conflicting evidence about the effect of age on concussion risk and recovery within the adolescent age range. The heterogeneity of results may be partially due to the use of age groupings based on convenience, making comparisons across studies difficult. This study evaluated the independent effect of age on concussion incidence, severity, and recovery in student-athletes aged 12-18 years using cluster analysis to define groupings.

METHODS

Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) scores of 11,403 baseline tests and 4922 postinjury tests were used to calculate the incidence rates for adolescent student-athletes grouped into 3 age bands (12-13, 14-15, and 16-18 years of age) on the basis of clustering analysis. The recently created Severity Index was used to compare concussion severity between groups. Follow-up tests for subjects who sustained a concussion were used to evaluate recovery time. The chi-square test and 1-way ANOVA were used to compare differences in demographic characteristics and concussion incidence, severity, and recovery. Multivariable logistic and linear regressions were used to evaluate the independent effects of age on concussion incidence and severity, respectively. Multivariable Cox hazard regression was used to evaluate differences in recovery time. Further analyses were conducted to directly compare findings across studies on the basis of the age groupings used in prior studies.

RESULTS

Multivariable regression analyses demonstrated that the 14- to 15-year-old age group had a significantly higher concussion incidence than both the 12- to 13-year-old (14- to 15-year-old group vs 12- to 13-year-old group, OR 1.57, 95% CI 1.16-2.17, p = 0.005) and 16- to 18-year-old (16- to 18-year-old group vs 14- to 15-year-old group, OR 0.79, 95% CI 0.69-0.91, p = 0.0008) age groups. There was no difference in incidence between the 12- to 13-year-old and 16- to 18-year-old groups (16- to 18-year group vs 12- to 13-year group, OR 1.26, 95% CI 0.93-1.72, p = 0.15). There were also no differences in concussion severity or recovery between any groups.

CONCLUSIONS

This study found that concussion incidence was higher during mid-adolescence than early and late adolescence, suggesting a U-shaped relationship between age and concussion risk over the course of adolescence. Age had no independent effect on concussion severity or recovery in the 12- to 13-, 14- to 15-, and 16- to 18-year-old groups. Further analysis of the various age groups revealed that results may vary significantly with minor changes to groupings, which may explain the divergent results in the current literature on this topic. Thus, caution should be taken when interpreting the results of this and all similar studies, especially when groupings are based on convenience.

Latent Representation of the Human Pan-Celltype Epigenome Through a Deep Recurrent Neural Network

The availability of thousands of assays of epigenetic activity necessitates compressed representations of these data sets that summarize the epigenetic landscape of the genome. Until recently, most such representations were cell type-specific, applying to a single tissue or cell state. Recently, neural networks have made it possible to summarize data across tissues to produce a pan-cell type representation. In this work, we propose Epi-LSTM, a deep long short-term memory (LSTM) recurrent neural network autoencoder to capture the long-term dependencies in the epigenomic data. The latent representations from Epi-LSTM capture a variety of genomic phenomena, including gene-expression, promoter-enhancer interactions, replication timing, frequently interacting regions, and evolutionary conservation. These representations outperform existing methods in a majority of cell types while yielding smoother representations along the genomic axis due to their sequential nature.

Effects of a history of headache and migraine treatment on baseline neurocognitive function in young athletes

Objective/background

Despite the prevalence of concussions in young athletes, the impact of headaches on neurocognitive function at baseline is poorly understood. We analyze the effects of a history of headache treatment on baseline ImPACT composite scores in young athletes.

Methods

A total of 11,563 baseline ImPACT tests taken by 7,453 student-athletes ages 12-22 between 2009 and 2019 were reviewed. The first baseline test was included. There were 960 subjects who reported a history of treatment for headache and/or migraine (HA) and 5,715 controls (CT). The HA cohort included all subjects who self-reported a history of treatment for migraine or other type of headache on the standardized questionnaire. Chi-squared tests were used to compare demographic differences. Univariate and multivariate regression analyses were used to assess differences in baseline composite scores between cohorts while controlling for demographic differences and symptom burden.

Results

Unadjusted analyses demonstrated that HA was associated with increased symptoms (β=2.30, 95% CI: 2.18-2.41, p<.0001), decreased visual memory (β=-1.35, 95% CI: -2.62 to -0.43, p=.004), and increased visual motor speed (β=0.71, 95% CI: 0.23-1.19, p=.004) composite scores. Baseline scores for verbal memory, reaction time, and impulse control were not significantly different between cohorts. Adjusted analyses demonstrated similar results with HA patients having greater symptom burden (β=1.40, 95% CI: 1.10-1.70, p<.0001), lower visual memory (β=-1.25, 95% CI: -2.22 to -0.27, p=.01), and enhanced visual motor speed (β=0.60, 95% CI: 0.11-1.10, p=.02) scores.

Conclusion

HA affected symptom, visual motor speed, and visual memory ImPACT composite scores. Visual memory scores and symptom burden were significantly worse in the HA group while visual motor speed scores were better, which may have been due to higher stimulant use in the HA group. The effects of HA on visual motor speed and visual memory scores were independent of the effects of the increased symptom burden.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-022-01432-w.

Subspecialty and Training Preferences for United States Neurosurgery Faculty with International Training

BACKGROUND

Academic neurosurgeons with international medical training play a large role in the US neurosurgical workforce. We aim to compare US trained with internationally trained neurosurgeons to uncover differences in subspecialty preferences and training opportunities abroad.

METHODS

1671 neurosurgeons from 115 ACGME accredited neurosurgical residency programs were identified in 2020. Data on demographics, institution characteristics, and chosen subspecialty were collected and faculty were divided based on location of training. Univariate analysis and multivariable logistic regression compared faculty characteristics between training locations.

RESULTS

Compared to the US Medical School+US Residency group, the international medical graduate (IMG)+US residency group was more likely to subspecialize in oncology/skull base and vascular neurosurgery and complete a fellowship in the US or internationally (p<0.05). The IMG+International residency group was more likely to subspecialize in oncology/skull base, more likely to do an international fellowship, and less likely to practice general neurosurgery (p<0.05). Pediatrics, radiosurgery, and vascular subspecialties were more likely to receive fellowship training in any location (p<0.05). Additionally, functional neurosurgeons were more likely to complete fellowships internationally, spinal neurosurgeons were less likely to pursue international fellowships, and peripheral nerve neurosurgeons were more likely to have dual fellowship training in both the US and abroad (p<0.05).

CONCLUSIONS

International medical training affected subspecialty choice and fellowship training. Internationally trained neurosurgeons more often specialized in oncology and vascular neurosurgery. Functional neurosurgeons were more likely to complete international fellowships, spine neurosurgeons were less likely to complete international fellowships, and peripheral nerve neurosurgeons more often had both US and international fellowships.

High altitude modulates concussion incidence, severity, and recovery in young athletes

BACKGROUND

High altitude may affect concussion, but prior studies are limited . We tested whether high altitude affects sport-related concussion (SRC) incidence, severity, and recovery.

METHODS

Twenty-five thousand eight hundred fifteen baseline and post-injury Immediate Post-Concussion Assessment and Cognitive Testing results were compiled from Florida and Colorado, low (27 m or 62 m) and high (1,640 m or 1,991 m) altitude locations, respectively. Incidence, severity, and recovery of injury were compared between altitudes.

RESULTS

High altitude was associated with increased suspected concussion incidence (adjusted OR, 2.04 [95% CI, 1.86 to 2.24];P < .0001). However, high altitude was associated with lower concussion severity measured by Severity Index (SI) (adjusted OR, 0.42 [95% CI, 0.37 to 0.49];P < .0001). High altitude was associated with decreased recovery from post-concussive symptoms in the migraine (β, -2.72 [95% CI, -3.31 to -2.13]; P < .0001), cognitive (β, -1.88 [95% CI, -2.40 to -1.36]; P < .0001), and sleep symptom clusters (β, -0.30 [95% CI, -0.52 to -0.08]; P = .007). Athletes with initial SI≥8 showed prolonged neurocognitive dysfunction at high altitude (HR, 1.38 [95% CI, 1.06 to 1.81]; P = .02).

CONCLUSIONS

High altitude was associated with increased suspected concussions and prolonged recovery but less severe initial injury.

Incidence and Severity of Concussions Among Young Soccer Players Based on Age, Sex, and Player Position

Background:

Previously studied risk factors for sports-related concussion in soccer players include sex, age, and player position. However, prior studies were limited in number, they reported conflicting results, and most did not assess initial concussion severity.

Purpose/Hypothesis:

The purpose of this study was to conduct an in-depth analysis of soccer players across key demographic groups (sex, age, position) for both concussion incidence and severity. It was hypothesized that concussion incidence and severity would be higher among male players, players aged ≥17 years, and goalkeepers.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

The authors analyzed baseline and postinjury ImPACT (Immediate Post-Concussion Assessment and Cognitive Testing) scores for athletes aged 12 to 22 years between July 2009 and June 2019. Players were assigned to an age group based on when they had their most recent baseline test. Concussion incidence and concussion severity index were compared using t tests and multivariate logistic regression.

Results:

For 1189 individuals who reported soccer as their primary sport, 1032 contributed 1754 baseline ImPACT tests (some individuals had multiple baseline tests), whereas 445 individuals were suspected of sustaining a concussion and then referred for a postinjury 1 test. Of these players, 254 (24.6%) had both a baseline and a postinjury test and were analyzed for concussion severity. Linear regression showed that forwards had a lower incidence of ImPACT-proxied concussions than goalkeepers had (P = .008). Female players had a significantly higher incidence of ImPACT concussions compared with male players (mean, 0.07 [female] vs 0.04 [male] concussions per person-year; P = .05). Players in the ≥17-year age group had a higher incidence of ImPACT concussions than players in the 15- to 16-year age group (P = .04), although the 15- to 16-year age group had more severe concussions than the ≥17-year age group (mean severity index, 2.91 [age 15-16 years] vs 1.73 [age ≥17 years]; P = .001).

Conclusion:

Female soccer players experienced a higher incidence of concussion than did male players, and goalkeepers experienced a greater incidence of ImPACT concussions than did forwards. Players of both sexes and all positions in the 15- to 16-year age group showed increased initial concussion severity compared with the ≥17-year age group, despite a lower comparative incidence of ImPACT concussions. Further study is needed to understand whether sex and player position affect concussion severity.

Bibliometric Evaluation of U.S. Neurosurgery Subspecialties and Academic Rank Using RCR Index

INTRODUCTION

Academic productivity, a key feature of academic neurosurgery, has been linked to academic rank, subspecialty, and institutional rank. Relative Citation Ratio (RCR) has emerged as a new metric of scholarly output that can make field-normalized comparisons between researchers, a feature unavailable in prior metrics such as h-index. Here we evaluate the influence of academic rank and neurosurgical subspecialties on RCR scores.

METHODS

We identified 1640 academic neurosurgeons from 115 ACGME-accredited programs in the United States, along with their neurosurgical specialty and demographic information, using publicly available data. Mean RCR (m-RCR) and weighted RCR (w-RCR) for each neurosurgeon were queried from the iCite database, which included publications from 2002-2020. m-RCR and w-RCR scores were compared across subspecialties and academic rank using multivariable regression while controlling for demographic factors.

RESULTS

Multivariable analysis indicated that academic neurosurgeons in general neurosurgery (P = 0.039) and pediatric neurosurgery (P = 0.003) had lower m-RCR scores than their peers in other subspecialties. w-RCR did not differ significantly among subspecialties. Higher academic rank was associated with increased m-RCR (P < 0.05) and w-RCR scores (P < 0.0001).

CONCLUSIONS

Professors have a higher m-RCR score relative to assistant professors, while general and pediatric neurosurgery were linked to lower m-RCR values. Although neurosurgical subspecialty choice did not influence w-RCR, a higher w-RCR score corresponded to a higher academic rank. Overall, the RCR metric can be utilized for field-normalized comparisons of faculty who differ in academic rank and subspecialty.

Impact of Psychiatric Illnesses and Selective Serotonin Reuptake Inhibitor Medications on Baseline Neurocognitive Testing

INTRODUCTION

Neurocognitive tests are an integral component of sport-related concussion (SRC) workup. A history of psychiatric illness (HPI) is common among young athletes. Investigations of factors that influence athletes' baseline neurocognitive function are crucial for an accurate assessment of SRC.

OBJECTIVE

In this study, we aim to elucidate the effect of HPI and selective-serotonin reuptake inhibitor (SSRI) medication use on baseline neurocognitive performance in young athletes.

METHODS

We conducted a retrospective cross-sectional study of Immediate Post-Concussion Assessment and Cognitive Testing assessments. A total of 268 athletes with HPI and a control group of 6,364 athletes were included. The outcomes were total symptom score based on post-concussion symptom scale, verbal memory, visual memory, visual motor, reaction time, and impulse control scores with self-reported HPI status and SSRI use.

RESULTS

Athletes with HPI had an elevated symptom score in both univariate analysis (p < .0001) and multivariate analysis (p < .0001). HPI influence on visual memory score was not robust to multivariate analysis (p = .24). Athletes with HPI who reported SSRI medication use had the same baseline neurocognitive performance as other athletes with HPI. HPI influences athletes' baseline neurocognitive performance by elevating symptom scores. HPI does not alter any of the objective neurocognitive composite scores in contrast to previous work.

CONCLUSIONS

Clinicians should consider the impact of HPI on baseline neurocognitive performance during the assessment of a suspected SRC. Additional research is required to bolster our findings on SSRI use and ascertain the effects of other drug classes on baseline neurocognitive performance.

Effects of Recurrent Mild Traumatic Brain Injuries on Incidence, Severity, and Recovery of Concussion in Young Student-Athletes

OBJECTIVE

To examine the effects of recurrent concussions on the incidence, severity, and recovery of significant neurocognitive dysfunction (SND) in young athletes.

SETTING

Various US youth sports organizations that utilize Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for baseline and postinjury concussion testing.

PARTICIPANTS

Data from 11 563 ImPACT baseline evaluations of US student-athletes aged 12 to 22 years were separated into 2 cohorts: subjects reporting 2 or more previous concussions (PC; n = 976 baseline evaluations) at baseline and a control group reporting zero previous concussions (CT; n = 7743 baseline evaluations). Subjects reporting 1 prior concussion were excluded.

DESIGN

Retrospective cohort.

MAIN MEASURES

Differences in SND incidence, severity, and recovery between the 2 cohorts were assessed using chi-squared tests, t tests, survival analyses, and multivariate regressions.

RESULTS

The PC cohort had a higher incidence of head injury leading to ImPACT (436.7 per 1000 person-years vs 194.4 per 1000 person-years, P < .0001) and a higher incidence of SND (140.4 vs 71.8, P < .0001) than controls. However, the Severity Index (SI) demonstrated that SND severity was lower in the PC group (7.55 vs 8.59, P = .04). Adjusted analyses similarly demonstrated that the PC cohort had increased SND incidence (odds ratio = 1.93; 95% CI, 1.61 to 2.31; P < .0001), decreased SI (β = -1.37; 95% CI, -2.40 to -0.34; P = .009), and equivalent recovery (hazard ratio = 0.98; 95% CI, 0.76 to 1.72; P = .90).

CONCLUSION

Participants with a history of concussion have a higher incidence of SND but present with lower severity SND, which may be a result of increased concussion education or symptom awareness. Recurrent concussion has no significant impact on acute neurocognitive recovery. Together, these results provide evidence against the supposition that a history of concussion increases the severity of future SND.

Academic Productivity of United States Neurosurgeons Trained Abroad

BACKGROUND

Previous research in neurosurgery has examined academic productivity for U.S. medical graduates and residents. However, associations between scholarly output and international medical education, residency training, and fellowship training are scarcely documented.

METHODS

We identified 1671 U.S. academic neurosurgeons in 2020 using publicly available data along with their countries of medical school, residency, and fellowship training. Using Scopus, h-index, number of publications, and number of times publications were cited were compiled. Demographic, subspeciality, and academic productivity variables were compared between training locations using univariate analysis and multivariable linear regression.

RESULTS

Of the current neurosurgery faculty workforce, 16% completed at least 1 component of their training abroad. Canada was the most represented international country in the cohort. Academic productivity for neurosurgeons with international medical school and/or international residency did not significantly differ from that of neurosurgeons trained in the United States. Neurosurgeons with ≥1 U.S. fellowships or ≥1 international fellowships did not have higher academic productivity than neurosurgeons without a fellowship. However, dual fellowship training in both domestic and international programs was associated with higher mean h-index (β = 6.00, 95% confidence interval 1.01 to 10.98, P = 0.02), higher citations (β = 2092.0, 95% confidence interval 460.1 to 3724.0, P = 0.01), and a trend toward higher publications (β = 36.82, 95% confidence interval -0.21 to 73.85, P = 0.051).

CONCLUSIONS

Neurosurgeon scholarly output was not significantly affected by international training in medical school or residency. Dual fellowship training in both a domestic and an international program was associated with higher academic productivity.

Sex-Related Differences in the Incidence, Severity, and Recovery of Concussion in Adolescent Student-Athletes Between 2009 and 2019

BACKGROUND

The sex of an athlete is thought to modulate concussion incidence; however, the effects of sex on concussion severity and recovery are less clear.

PURPOSE

To evaluate sex differences in concussion severity and recovery using a large, heterogeneous sample of young student-athletes with the goal of understanding how sex affects concussion outcomes in young athletes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

The Immediate Post-Concussion Assessment and Cognitive Testing results of 11,563 baseline and 5216 postinjury tests were used to calculate the incidence of concussion of adolescent male and female student-athletes ages 12 to 22 years (median, 15 years). The postinjury tests of 3465 male and 1751 female student-athletes evaluated for concussion or head trauma were used to assess differences in the Severity Index (SI) and recovery. Chi-square tests and t tests were used to compare differences in demographic characteristics, incidence, and SI between the 2 cohorts. Multivariable linear, logistic, and Cox proportional hazards regressions were used to control for differences between cohorts in analyses of incidence, SI, and recovery.

RESULTS

When we controlled for demographic differences, female participants had higher odds of concussion (odds ratio, 1.62; 95% CI, 1.40-1.86; P < .0001) and higher SI after concussion (β = 0.67; 95% CI, 0.02-1.32; P = .04). This discrepancy in SI was a result of differences in Symptom (2.40 vs 2.94; P < .0001) and Processing Speed (0.91 vs 1.06; P = .01) composite scores between male and female participants, respectively. We found no effect of sex on time to recovery when controlling for initial concussion SI (hazard ratio, 0.94; 95% CI, 0.78-1.12; P = .48).

CONCLUSION

Using large, multisport cohorts, this study provides evidence that female athletes are at higher risk for more concussions and these concussions are more severe, but male and female athletes have similar recovery times when the analysis controls for initial concussion SI.

Sport Contact Level Affects Post-Concussion Neurocognitive Performance in Young Athletes

OBJECTIVE

Contact level affects the incidence of sports-related concussion. However, the effects of contact level on injury severity and recovery are less clear and are the focus of this study.

METHOD

Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT) for athletes aged 12-22 was performed at baseline (n = 10,907 for 7,058 athletes), after suspected concussion determined by physicians or athletic trainers (n = 5,062 for 4,419 athletes), and during follow-up visits (n = 3,264 for 2,098 athletes). Athletes played contact/collision (CC), limited contact (LC), and noncontact (NC) sports. Injury incidence, severity, and recovery were measured using raw and change from baseline neurocognitive test scores. Comparisons between groups used univariate analysis and multivariable regression controlling for demographic variables.

RESULTS

Compared to CC athletes, LC and NC athletes showed decreased suspected concussion incidence. At initial post-injury testing, all neurocognitive test scores were similar between groups except changes from baseline for processing speed were improved for LC compared to CC athletes. Upon follow-up testing, raw neurocognitive scores were better for NC compared to the contact collision athletes in verbal memory, processing speed, total symptom score, migraine cluster, cognitive cluster, and neuropsychiatric cluster scores. For change from baseline scores, LC athletes exhibited better performance on verbal memory, processing speed, and reaction time but also showed higher neuropsychiatric scores than CC athletes.

CONCLUSION

Neurocognitive scores between contact levels were similar at the first post-injury test. However, follow up showed many improved scores and symptoms for limited and NC sports compared to CC sports, which may indicate faster recovery.

Policy Interventions, Social Distancing, and SARS-CoV-2 Transmission in the United States: A Retrospective State-level Analysis

BACKGROUND

Various non-pharmaceutical interventions (NPIs) such as stay-at-home orders and school closures have been employed to limit the spread of Coronavirus disease (COVID-19). This study measures the impact of social distancing policies on COVID-19 transmission in US states during the early outbreak phase to assess which policies were most effective.

METHODS

To measure transmissibility, we analyze the average effective reproductive number (R_t) in each state the week following its 500th case and doubling time from 500 to 1000 cases. Linear and logistic regressions were performed to assess the impact of various NPIs while controlling for population density, GDP, and certain health metrics. This analysis was repeated for deaths with doubling time to 100 deaths with several healthcare infrastructure control variables.

RESULTS

States with stay-at-home orders in place at the time of their 500th case were associated with lower average R_t the following week compared to states without them (p<0.001) and significantly less likely to have an R_t>1 (OR 0.07, 95% CI 0.01-0.37, p = 0.004). These states also experienced longer doubling time from 500 to 1000 cases (HR 0.35, 95% CI 0.17-0.72, p = 0.004). States in the highest quartile of average time spent at home were also slower to reach 1000 cases than those in the lowest quartile (HR 0.18, 95% CI 0.06-0.53, p = 0.002).

CONCLUSIONS

Stay-at-home orders had the largest effect of any policy analyzed. Multivariate analyses with cellphone tracking data suggest social distancing adherence drives these effects. States that plan to scale back such measures should carefully monitor transmission metrics.

Multivariate Analysis of Black Race and Environmental Temperature on COVID-19 in the US

BACKGROUND

There has been much interest in environmental temperature and race as modulators of Coronavirus disease-19 (COVID-19) infection and mortality. However, in the United States race and temperature correlate with various other social determinants of health, comorbidities, and environmental influences that could be responsible for noted effects. This study investigates the independent effects of race and environmental temperature on COVID-19 incidence and mortality in United States counties.

METHODS

Data on COVID-19 and risk factors in all United States counties was collected. 661 counties with at least 50 COVID-19 cases and 217 with at least 10 deaths were included in analyses. Upper and lower quartiles for cases/100,000 people and halves for deaths/100,000 people were compared with t-tests. Adjusted linear and logistic regression analyses were performed to evaluate the independent effects of race and environmental temperature.

RESULTS

Multivariate regression analyses demonstrated Black race is a risk factor for increased COVID-19 cases (OR=1.22, 95% CI: 1.09-1.40, P=0.001) and deaths independent of comorbidities, poverty, access to health care, and other risk factors. Higher environmental temperature independently reduced caseload (OR=0.81, 95% CI: 0.71-0.91, P=0.0009), but not deaths.

CONCLUSIONS

Higher environmental temperatures correlated with reduced COVID-19 cases, but this benefit does not yet appear in mortality models. Black race was an independent risk factor for increased COVID-19 cases and deaths. Thus, many proposed mechanisms through which Black race might increase risk for COVID-19, such as socioeconomic and healthcare-related predispositions, are inadequate in explaining the full magnitude of this health disparity.

Assessing the predictive value of primary evaluation with the Immediate Post-Concussion Assessment and Cognitive Test following head injury

OBJECTIVE

Concussions are a major public health concern, especially for high school and college student athletes. However, there are few prognostic metrics that can accurately quantify concussion severity in order to anticipate recovery time and symptom regression. The Immediate Post-Concussion Assessment and Cognitive Test (ImPACT) is a widely used neurocognitive assessment that can diagnose and track recovery from concussions. This study assesses whether initial ImPACT scores, collected within 48 hours of the injury, can predict persistence of concussion at follow-up.

METHODS

Results from 6912 ImPACT tests were compiled in 2161 unique student athletes, ages 12-22 years. The authors defined a novel metric, the Severity Index (SI), which is a summation of the number of standard deviations from baseline at the 80% CI for each of the 5 composite scores reported by ImPACT. Patients were binned into groups based on SI (0-3.99, 4-7.99, 8-11.99, 12+) and the relationships between SI groups, composite scores, symptom profiles, and recovery time were characterized using 1-way and 2-way ANOVAs and Kaplan-Meier plots. A logistic regression assessed the value of SI for predicting concussion at follow-up.

RESULTS

Patients with a higher SI at diagnosis were more likely to still be concussed at their first follow-up (F3,2300 = 93.06; p < 0.0001). Groups with a higher SI also displayed consistently slower recovery over a 42-day period and were more likely to report symptoms in all 4 symptom clusters (Migraine, Cognition, Sleep, and Neuropsychiatric). When controlling for sex, age, number of previous concussions, days between assessments, and location, SI significantly increased the odds of being concussed at follow-up (OR 1.122, 95% CI 1.088-1.142; p < 0.001). This model showed good discrimination with an area under the curve of 0.74.

CONCLUSIONS

SI is a useful prognostic tool for assessing head injury severity. Concussions with higher initial SI tend to last longer and have broader symptomatic profiles. These findings can help patients and providers estimate recovery based on similar ImPACT score profiles.

The Effect of Game Importance on Concussion Incidence in the National Football League: An Observational Study

Introduction Concussion incidence in the National Football League (NFL) has been shown to generally increase as the season progresses. Yet, there is evidence that suggests that the incidence stagnates or decreases in the final quarter of the season in comparison to the third quarter. This anomaly cannot be explained by any of the known modulators of concussion incidence. However, the fact that the teams start getting eliminated from playoff contention in the fourth quarter of the season may explain this pattern in concussion incidence. This study tests whether there is a difference in concussion incidence in games between teams who are still in the playoff hunt [in the hunt (IH) games] versus games where both teams have had their playoff fate already determined (non-IH games). Methods We obtained details of 166 documented concussions from weeks 13-16 of each of the four NFL seasons from 2012 to 2015 from Public Broadcasting Service's (PBS) Frontline Concussion Watch and matched them to the games in which they occurred. Each game was categorized based on the playoff status [clinched (CL), eliminated (EL), or IH] of the teams playing in the game. Concussion incidence of the game types was compared to each other using a one-way analysis of variance (ANOVA) test and student t-tests. Additionally, concussion incidences at six different player positions in important games were compared to the corresponding incidences in unimportant games. An ordinary least squares regression was used to examine the effects of game importance and plays per game on concussion incidence. Results Concussion incidence in important games (mean = 0.651 ±0.055) did not differ significantly (p: 0.890) from the incidence in unimportant games (mean = 0.623 ±0.143). Instead, plays per game was found to be the primary driver of concussion in the regression analysis (β = 0.01605; p: 0.025). At the position-specific level, running backs (RB) were the only position to demonstrate a significant increase in concussion incidence (p: 0.004) in important games (mean = 0.049 ±0.017) compared to unimportant games (mean = 0.00 ±0.00). Conclusions The results suggest that, in general, players are not more likely to suffer concussions in IH games than in non-IH games. However, RBs may have an increased risk of concussion in games with playoff implications than in games without.

Aneurysmal Subarachnoid Hemorrhage with Spinal Subdural Hematoma: A Case Report and Systematic Review of the Literature

OBJECTIVE

Spinal subdural hematoma (S-SDH) rarely occurs after aneurysmal subarachnoid hemorrhage (SAH). Little information is known regarding the management and prognosis of patients with both S-SDH and SAH. Here, we present an illustrative case and provide a systematic review of S-SDH in the setting of SAH.

METHODS

A systematic literature review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines revealed 11 previous cases of concurrent intracranial SAH and spinal SDH, which are presented with our new reported case.

RESULTS

Intracranial sources of spontaneous SAH included 8 aneurysms, 1 pseudoaneurysm, and 3 angiogram-negative cases. Hunt Hess grades ranged from 1 to 4, mean time between SAH and S-SDH was 5.8 days, and S-SDH presented most frequently in the lumbar spine. Eight patients showed significant to complete clinical recovery, 2 had continued plegia of the lower extremities, and 2 expired. Modified Rankin scores (mRS) ranged from 0 to 6, with mRS >2 for 4 of 12 patients. Patients with a poor clinical outcome (mRS >2) had an initially negative cerebral angiogram, earlier presentation with less time between SAH and S-SDH (0.8 vs. 7.6 days), use of antithrombotic medication, no diversion of cerebrospinal fluid, and cervical or thoracic S-SDH.

CONCLUSION

S-SDH is uncommon in the setting of aneurysmal SAH; better outcomes are associated with lumbar location, delayed presentation, cerebrospinal fluid diversion, and lack of antithrombotic use. Conservative treatment may be sufficient in patients with delayed S-SDH and lack of significant neurologic deficits. More reported cases will allow greater understanding of this clinical entity.

[Teleost Type 2 Interleukin-1 Receptor (IL-1R2) from the Spotted Halibut (Verasper variegatus): 3D Structure and a Role in Immune Response]

The type 2 interleukin-1 receptor (IL-1R2) is one of natural IL-1β singling inhibitors in mammals. We cloned and sequenced the IL-1R2 gene in V. variegatus (VvIL-1R2). The phylogenetic analysis showed that the molecular structure VvIL-1R2 is similar to that of its orthologues in other vertebrates. The expression levels of VvIL-1R2 are relatively high in the peripheral blood leukocytes (PBLs), gill, and spleen. In addition, peculiar expression patterns for his molecule were detected at various developmental stages, implying that in flatfishes the IL-1R2 may have be important for embryonic development and metamorphosis. In PBLs, the treatment with pathogen-associated molecular patterns (PAMPs) induced a significant and rapid up-regulation of VvIL-1R2, pointing at its involvement in the immune responses against bacterial and viral pathogens.

Dynamic Cervical Cord Compression Post-laminectomy Visualized by Flexion-extension Magnetic Resonance Imaging: Case Report

Flexion-extension magnetic resonance imaging (MRI) in the cervical spine is not universally used in cervical spine surgery. However, flexion-extension MRIs can identify previously undetected spinal stenosis, improve surgical decision-making, and maybe a better tool to evaluate postoperative outcomes. One uncommon complication after laminectomy, to treat cervical spinal stenosis, is muscle weakness due to subsequent dynamic cord compression by posterior paraspinal musculature. We present a case of a 41-year-old male who underwent posterior cervical decompression and developed subsequent neurological deficits and muscle weakness. MRI with neutral cervical positioning did not show spinal stenosis necessitating surgical intervention. However, given the patient’s increasing tetraparesis, flexion-extension MRI was performed and it revealed significant spinal stenosis in both flexion and extension positions due to spondylosis and compression from paraspinal muscles. This case demonstrates the utility of flexion-extension MRI in identifying pathologies such as cord compression by paraspinal muscles. Exclusive use of a neutral-position MRI scan may not be sufficient to provide proper diagnoses for cervical spine pathologies. Flexion-extension MRI should be considered when the degree of neurological symptoms outweighs minimal or absent pathology seen on neutral-position sagittal MRI.

Effects of Game Characteristics and Player Positions on Concussion Incidence and Severity in Professional Football

Background:

Increasing efforts have been made to reduce the incidence and severity of concussion in high-contact sports. Despite these efforts, a relative lack of knowledge is available regarding modulating factors affecting concussion injury.

Purpose:

To analyze the potential influence of game characteristics and outcomes on concussion incidence and severity in professional football.

Study Design:

Descriptive epidemiology study.

Methods:

PBS Frontline Concussion Watch was used to collect concussion injury data from regular-season games of 32 National Football League (NFL) teams from 2012 to 2015. Game characteristic variables such as rushing and passing attempts, turnovers, and margin of victory were collected from ESPN. Analysis included descriptive statistics, analysis of variance, t tests, and correlation tests.

Results:

Away teams demonstrated a significantly greater concussion incidence per game than home teams. Losing teams had a significantly greater concussion incidence per game than winning teams. Being both the away team and the losing team appeared to have an additive effect. The home-versus-away and win-versus-loss effects were significant for offensive but not defensive positions. Within individual positions, significantly greater concussion incidence was associated with tight ends, running backs, wide receivers, and cornerbacks. When running versus passing positions were compared, passing positions (wide receiver, tight end, cornerback, safety) had significantly greater concussion incidence. A total of 626 games were missed as a result of reported concussions. Away teams had significantly more games missed due to concussion when they lost. Play time did not significantly differ before or after concussion injury. Other game characteristic variables did not significantly affect concussion frequency or intensity.

Conclusion:

Position, game location, and game outcome affect concussion incidence for professional football players. In a subset of analyses, the number of games missed aligned with concussion incidence, but this appeared to be an imperfect measure. These findings highlight new factors that may modulate concussion incidence and merit further study on how they may influence concussion evaluation.

Does the Environment Influence the Frequency of Concussion Incidence in Professional Football?

Background

Sports-related concussion is a major cause of mild traumatic brain injury (mTBI). It is possible that environmental factors, such as temperature, humidity, and stadium's altitude, may influence the overall incidence of concussions during a game.

Purpose

To examine the impact of environmental factors, such as temperature, humidity, barometric pressure, and dew point, on concussion incidence.

Methods

Public Broadcasting Service (PBS) FRONTLINE Concussion Watch was used to collect injury data on 32 NFL teams during regular season games from 2012 to 2015. Weather data points were collected from Weather Underground. Concussion incidence per game, the probability of a concussion during a game, and a difference in mean game-day temperature, humidity, dew point, and barometric pressure between concussion and concussion-free games were calculated. Our analysis included t-tests, analysis of variance (ANOVA), multivariate correlation tests, and logistic and Poisson regression. 

Results

Overall, 564 concussions were reported. There were 411 games with concussions and 549 games without concussions. We observed a significant decrease in concussion incidence with increasing temperature, both when the temperature was divided into 20^oF increments or into quartiles (p = 0.005 and p = 0.002, respectively). We identified a statistically significant lower mean-game day temperature in concussion games compared to concussion-free games (p < 0.0006). We also observed a significant decrease in the incidence of concussion per game with increasing dew point. There was no significant difference in concussion incidence in barometric pressure and humidity. The logistic regression model predicted a decrease in the probability of a concussion in games with higher temperatures and dew points.

Conclusions

National Football League (NFL) players experienced an increased risk of concussion during football games played in colder temperatures and at lower dew points. Further research on environmental effects on concussions may aid in improving player safety in football leagues.

Modifying Factors for Concussion Incidence and Severity in the 2013-2017 National Hockey League Seasons

Introduction

In the past few years, there has been a rising interest in both the prevalence and the short- and long-term consequences of concussions. While the main focus of concussion-based research revolves around the National Football League (NFL), attention is now shifting to other high contact leagues like the National Hockey League (NHL), where there is constant player-to-player contact as well as collisions with the perimeter boards. While the body of evidence surrounding injury and concussion rates in the NHL has substantially grown in size over the previous few years, there is still a void pertaining to the in-game effects that could modulate concussion incidence. Our study takes a novel approach to evaluate several “style of play” factors such as home/away perspective, win/loss outcome, points scored, real time length of game, time of season, and player position in modulating concussion rates.

Methods

Data on concussion incidence for the 2013-2017 National Hockey League seasons was collected utilizing FOX Sports injury tracker. Only injuries specifically diagnosed as concussions during regular and postseason games were utilized in our data set. A Google search on the reported injury was performed in order to correlate the concussion to the correct game in which the player sustained it. NHL season schedules were acquired through the online source “Hockey Reference.” There were a total of 5281 games when considering the regular and postseason games between the 2013-2017 seasons. Concussions sustained during team practices and preseason contests were not accounted for in our data set to control for inconsistent reporting. Our data set does not account for the current 2017-2018 NHL expansion with the addition of a Las Vegas team to the league.

Results

Statistical analysis of several "Style of Play" factors such as home/away perspective, win/loss outcome, points scored, real time length of game and time of season produced non-significant results pertaining to modulating concussion rate during the 2013-2017 NHL seasons. When evaluating on-ice position we noted offensive players combined to have the highest rate of concussion. Forwards (left wing (LW), right wing (RW)) demonstrated similar concussion rates, while goalies encountered the lowest concussion rate.

Conclusion

The results of our analysis demonstrated non-significance for home/away effects, win/loss results, average points scored, real time length of game, and time of season on influencing concussion rates. We noted offensive players combined to have the highest rate of concussions, while goalies encountered the least. The key limitation in our data set is the lack of reliable and publicly available data surrounding concussion incidence in the National Hockey League. Due to this drawback, our data set should be considered as an under-reported representation of the total amount of concussions spanning the 2013-2017 seasons.

Evaluation of Concussion Incidence and Modulating Factors in the 2013-2017 Australian Football League

Introduction

The increasing awareness and popularization of concussions in the research realm over the last few years have begun to shed more light on the detrimental effects associated with repetitive head trauma. While the majority of the current literature focuses on the National Football League (NFL) and National Hockey League (NHL), several other high-impact sports have been implementing concussion management protocols to protect their players. The Australian Football League (AFL) is a prime example of a major contact sport that has undertaken recent changes to its concussion assessment and management modalities. We recognize the benefit of reporting potential changes in concussion rates over the 2013-2017 AFL seasons. We were interested in some of the factors not yet evaluated before, which may contribute to the overall concussion incidence such as “style-of-play” factors” (home/away, win/loss, points scored, time of season). We hope the results of this analysis shed light on the mechanisms by which concussion rates can be mitigated across major contact sports.

Methods

Data were obtained from the weekly injury list published by the AFL, a publicly available website. Details of players listed with concussions were collected from regular season games (890 games total) of 18 AFL teams from 2013 to 2017. Weekly injury lists were retrospectively compared using THE AGE, a publicly available newspaper published and owned by Fairfax Media. Data were analyzed utilizing GraphPad Prism 6 (GraphPad Software Inc., CA, US). In addition to descriptive statistics, Fisher's exact tests, Welch’s two-tailed t-tests, and correlation tests were used. Alpha level < 0.05 was considered significant for all tests.

Results

The dataset comprised 236 total concussions between the 2013 and 2017 AFL seasons. We noted a significant increase in the concussion rate (p = 0.0010) between the 2013 and 2017 seasons. This result was complemented by a significant increase in average games missed between the 2014 and 2015 seasons (p = 0.0002); however, this trend was not significant when evaluating the 2013 and 2017 seasons directly (p = 0.0951). Further analysis into the "style of play" factors on concussion incidence, such as average points scored, win/loss, home/away, and time of season, produced non-significant results.

Conclusion

Our study identified a significant increasing trend in concussion rate and average games missed that correlate to the data analysis in other high-impact sports such as the NFL and NHL. However, further research is necessary to determine if these findings indicate the improvement in concussion management and player safety measures beginning to develop in high-impact sports. We also noted that certain “style of play” factors (points scored, win/loss, home/away, and time of season) have no significant implication on concussion rate during the 2013-2017 AFL seasons. While we consider our data source to be reliable in the reporting of concussions from the AFL, the ideal data set would comprise a medical diagnosis from the team of doctors. It may be possible that our data set is underreporting the total amount of concussions between the 2013 and 2017 AFL seasons. Return-to-play times were not ascertained directly from the team doctor for the clearance date. It may be possible that this data collection modality led to missed cases of head injury or return to play times, which could impact the reliability of our dataset.

Spontaneous Arrest of Sporadic Spinal Hemangioblastoma Growth after Postoperative Nodular Recurrence: Case Report

Hemangioblastomas are rare, slow-growing, highly vascularized tumors of the central nervous system which often occur in the spinal cord. When presenting as sporadic, isolated tumors without Von-Hippel Lindau disease, they are curable through surgery with a low rate of recurrence. Tumor recurrence in these cases is usually associated with prior subtotal resection. However, to the best of our knowledge, cases of recurrent, sporadic spinal hemangioblastoma have not been reported to spontaneously arrest without intervention or symptoms. We report a patient who underwent an initial complete resection of a cervical spinal hemangioblastoma, a subtotal resection of tumor recurrence four and a half years later, and nine years of neurologic and radiographic stability with no additional interventions.

c-index and Subindices of the h-index: New Variants of the h-index to Account for Variations in Author Contribution

Objectives Bibliometrics are used to assess or compare the academic productivity of individuals or groups. Most of these metrics, including the widely used h-index, do not recognize the added contribution that is generally provided by authors listed first, second, second-to-last and last (enhanced positions) in a publication citation. We propose the c-index as a novel modification to the h-index that will better reflect an individual's academic output, incorporating authorship position. Methods One hundred and sixty-six academic neurosurgeons in eight New York City (NYC) metropolitan region training programs were identified through department websites. Using the Scopus citation database, bibliometric profiles were created for each surgeon. Once an individual's h-index was calculated, the h-core articles (those with h or more citations) were specifically assessed to determine citation author position. Novel bibliometric indices were created to reflect the number of h-core articles that accounted for primary (h_p), senior (h_s) or internal authorship (h_i) position. Weighted "involvement factors" for primary (i_p) and senior (i_s) author contribution were created to reflect the added value of "enhanced position" authorship in an individual's h-core publications. c-indices were created to reflect the author's h-index once augmented by primary (c_p), senior (c_s), and overall (c_o) "enhanced position" authorship. Comparisons were made within each institution and across institutions, according to academic rank (assistant professor, associate professor, professor and chairperson). Results Breakdown by academic rank showed an increasing average h-index progressing from assistant professor through professor rank with no significant difference demonstrated between professor and chair status. This pattern was seen across all departments (aggregate) but with fewer instances of significance at the level of individual departments. After h-index modification, c_p, c_s, and c_o indices showed a similarly significant trend. As faculty rank increased, there was a significant trend toward increasing numbers of articles with authors in enhanced positions and a higher percentage of articles with the author in a senior position. Academic faculty had higher h, c_p, and c_s indices than clinical faculty. Evaluation of each individual department revealed no significant trend regarding a department's higher average c_p or c_s. Average c-index for a department paralleled the average h-index of that department, with larger departments tending to have larger cumulative h, c_p, c_s, and c_o indices. No consistent correlation was seen between mean h-indices and academic rank at an individual departmental level. Conclusions This study examines the academic productivity of a subset of neurosurgical programs in the NYC metropolitan area as a test bed for novel bibliometric indices. h_p, h_i, and h_s represent the respective number of primary, internal and senior authorship papers that comprise an individual's h-core papers. c_p, c_s, and c_o, variations of the h-index metric, are designed to more accurately reflect the contributions by primary, secondary and senior authors. Increasing academic rank was associated with an increased number of articles with the author in enhanced positions and a higher percentage of articles in a senior position.

[Salubrinal improves cardiac function in rats with heart failure post myocardial infarction through reducing endoplasmic reticulum stress-associated apoptosis]

OBJECTIVE

Endoplasmic reticulum (ER) stress plays an important role in ischemia-mediated cell death. The aim of the current study is to investigate the effects of salubrinal (Sal), a selective eIF2a dephosphorylation inhibitor, on heart failure rats and related mechanisms.

METHODS

Heart failure was induced by coronary artery ligation (MI) in adult male Sprague-Dawley rats. To ensure comparable MI sizes post coronary artery ligation on various groups, echocardiography examination was performed before and 30 minutes after ligation in MI groups. Then rats were randomly assigned to 4 groups: Sham group (n=12), MI group (n=10), MI plus vehicle injections group (DMSO group, n=12) and MI plus Sal injection group (Sal group, n=12). Sal (1 mg/kg) or DMSO was injected via the tail vein daily for the first 3 days (starting at 30 minutes after ligation of the left coronary artery), followed by subcutaneous injections twice per week for 8 weeks. Cardiac function was assessed by echocardiography and cell apoptosis assessed by flow cytometric analysis after 8 weeks. Protein and mRNA levels of ER stress markers were evaluated by immunohistochemistry and real time RT-PCR respectively.

RESULTS

Eight weeks later, LVEF was significantly higher, while LVESD and LVEDD values were significantly lower in Sal group compared to MI and DMSO groups (all P<0.05); LV/BW ratio was significantly higher in MI group than in Sham group ((2.30±0.40) mg/g vs.(1.78±0.31) mg/g, P<0.05), which was significantly reduced in Sal group ((1.88±0.25) mg/g), but not in DMSO group((2.25±0.36) mg/g, P<0.05 vs. MI). In addition, flow cytometric analysis showed that Sal treatment significantly reduced apoptosis but not necrosis in post MI. Immunohistochemistry and real time PCR analysis showed that the myocardial protein and mRNA expression of ER stress markers were significantly lower in Sal group than in MI group, myocardial caspase-12 expression was significantly upregulated in MI group and significantly reduced by Sal treatment.

CONCLUSIONS

Our results suggest that reduction of ER stress and myocardial apoptosis through inhibition of eIF2α dephosphorylation may serve as the potential mechanisms for the improved cardiac function and attenuated cardiac remodeling post Sal treatment in this heart failure rat model.

Abstract POSTER-BIOL-1331: Nucleotide excision repair mutations confer sensitivity to platinum but not PARP-inhibitors in epithelial ovarian cancer

The marked platinum sensitivity of epithelial ovarian cancer (EOC) is thought to be related to underlying defects in the homologous recombination (HR) DNA repair pathway, which are present in approximately 50% of tumors with high-grade serous histology. However, repair of platinum-induced DNA damage does not always involve the HR pathway. More than 90% of platinum-DNA lesions are intrastrand cross-links which are repaired by the nucleotide excision repair (NER) pathway. We curated the TCGA ovarian cancer dataset and identified 22 tumors (7%) with nonsynonymous or splice site NER gene mutations among the 316 sequenced high grade serous ovarian tumors. All NER mutations were mutually exclusive and 8 (36%) were accompanied by heterozygous loss of the respective NER gene. In 12 (55%) of the 22 cases, there were no concomitant HR alterations identified. In vitro functional evaluation of two NER mutations (ERCC6-Q524* and ERCC4-A583T), identified in patients with advanced stage tumors and extreme response to first-line platinum therapy, showed that both mutations conferred platinum, but not PARPi, or doxorubicin sensitivity, and did not affect HR activity. Interestingly, ERCC6-Q524* was not associated with heterozygous loss but sensitized cells to platinum in a dominant negative fashion. Our findings suggest a novel mechanism of platinum sensitivity in EOC that involves NER gene mutations, which may occur independently of HR alterations. Unlike tumors with defective HR, tumors harboring only NER mutations may be sensitive to platinum but not PARP inhibition. Dissociation of platinum and PARPi sensitivity in this setting may have important implications for PARPi trials for both HR-proficient and HR-deficient EOCs.

Citation Format: Raphael Ceccaldi, Kevin O’Connor, Kent W. Mouw, Adam Y. Li, Ursula A. Matulonis, Alan D. D’Andrea, Panagiotis A. Konstantinopoulos. Nucleotide excision repair mutations confer sensitivity to platinum but not PARP-inhibitors in epithelial ovarian cancer [abstract]. In: Proceedings of the 10th Biennial Ovarian Cancer Research Symposium; Sep 8-9, 2014; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2015;21(16 Suppl):Abstract nr POSTER-BIOL-1331.

A new strategy for complete identification of sea buckthorn cultivars by using random amplified polymorphic DNA markers

DNA fingerprinting is both a popular and important technique with several advantages in plant cultivar identification. However, this technique has not been used widely and efficiently in practical plant identification because the analysis and recording of data generated from fingerprinting and genotyping are tedious and difficult. We developed a novel approach known as a cultivar identification diagram (CID) strategy that uses DNA markers to separate plant individuals in a more efficient, practical, and referable manner. A CID was manually constructed and a polymorphic marker was generated from each polymerase chain reaction for sample separation. In this study, 67 important sea buckthorn cultivars cultivated in China were successfully separated with random amplified polymorphic DNA markers using the CID analysis strategy, with only seven 11-nucleotide primers employed. The utilization of the CID of these 67 sea buckthorn cultivars was verified by identifying 2 randomly chosen groups of cultivars among the 67 cultivars. The main advantages of this identification strategy include fewer primers used and separation of all cultivars using the corresponding primers. This sea buckthorn CID was able to separate any sea buckthorn cultivars among the 67 studied, which is useful for sea buckthorn cultivar identification, cultivar-right-protection, and for the sea buckthorn nursery industry in China.

A unique subset of epithelial ovarian cancers with platinum sensitivity and PARP inhibitor resistance

Platinum and PARP inhibitor (PARPi) sensitivity commonly coexist in epithelial ovarian cancer (EOC) due to the high prevalence of alterations in the homologous recombination (HR) DNA repair pathway that confer sensitivity to both drugs. In this report, we describe a unique subset of EOC with alterations in another DNA repair pathway, the nucleotide excision repair (NER) pathway, which may exhibit a discordance in sensitivities to these drugs. Specifically, 8% of high-grade serous EOC from The Cancer Genome Atlas dataset exhibited NER alterations, including nonsynonymous or splice site mutations and homozygous deletions of NER genes. Tumors with NER alterations were associated with improved overall survival (OS) and progression-free survival (PFS), compared with patients without NER alterations or BRCA1/2 mutations. Furthermore, patients with tumors with NER alterations had similar OS and PFS as BRCA1/2-mutated patients, suggesting that NER pathway inactivation in EOC conferred enhanced platinum sensitivity, similar to BRCA1/2-mutated tumors. Moreover, two NER mutations (ERCC6-Q524* and ERCC4-A583T), identified in the two most platinum-sensitive tumors, were functionally associated with platinum sensitivity in vitro. Importantly, neither NER alteration affected HR or conferred sensitivity to PARPi or other double-strand break-inducing agents. Overall, our findings reveal a new mechanism of platinum sensitivity in EOC that, unlike defective HR, may lead to a discordance in sensitivity to platinum and PARPi, with potential implications for previously reported and ongoing PARPi trials in this disease.

Traditional Chinese medicine and related active compounds: a review of their role on hepatitis B virus infection

Since the significant public health hazard of Hepatitis B virus (HBV) infection and obvious drug resistance and dose-dependent side effects for common antiviral agents (e.g., interferon α, lamivudine, and adefovir), continuous development of agents to treat HBV infection is urgently needed. Traditional Chinese medicine (TCM) is an established segment of the health care system in China. Currently, it is widely used for chronic hepatitis B (CHB) in China and many parts of the world. Over a long period of time in clinical practice and in basic research progress, the effectiveness and beneficial contribution of TCM on CHB have been gradually known and confirmed. Based upon our review of related papers and because of our prior knowledge and experience, we have selected some Chinese medicines, including Chinese herbal formulas (e.g., Xiao-Chai-Hu-Tang, Xiao-Yao-San, and Long-Dan-Xie-Gan-Tang), single herbs (e.g., Phyllanthus niruri, Radix astragali, Polygonum cuspidatum, Rheum palmatum, and Salvia miltiorrhiza) and related active compounds (e.g., wogonin, artesunate, saikosaponin, astragaloside IV, and chrysophanol 8-O-beta-Dglucoside) and Chinese medicine preparations (e.g., silymarin, silibinin, kushenin, and cinobufacini), which seem effective and worthy of additional and indepth study in treating CHB, and we have given them a brief review. We conclude that these Chinese herbal medicines exhibit significant anti-HBV activities with improved liver function, and enhanced HBeAg and HBsAg sero-conversion rates as well as HBV DNA clearance rates in HepG2 2.2.15 cells, DHBV models, or patients with CHB. We hope this review will contribute to an understanding of TCM and related active compounds as an effective treatment for CHB and provide useful information for the development of more effective antiviral drugs.

In vitro and in vivo evaluation of cypermethrin, amitraz, and piperonyl butoxide mixtures for the control of resistant Rhipicephalus (Boophilus) microplus (Acari: Ixodidae) in the Mexican tropics

A study was conducted to evaluate the efficacy of cypermethrin, amitraz, and piperonyl butoxide (PBO) mixtures, through in vitro laboratory bioassays and in vivo on-animal efficacy trials, for the control of resistant Rhipicephalus (Boophilus) microplus on cattle in the Mexican tropics. Also, to examine mechanisms of resistance to cypermethrin in this tick population, the frequency of a mutated sodium channel gene (F1550I) was determined using a PCR assay. Results of laboratory bioassays using modified larval packet tests revealed that cypermethrin toxicity was synergized by PBO (from 46.6-57.0% to 83.7-85.0% larval mortality; P<0.05). The cypermethrin and amitraz mixture showed an additive effect (from 46.6-57.0% to 56.0-74.3% larval mortality). Strong synergism was observed with the mixture of cypermethrin+amitraz+PBO and this mixture was the most effective killing resistant tick larvae in vitro (96.7-100% of larval mortality). Tick larvae surviving exposure to cypermethrin or mixtures either with amitraz and PBO in vitro showed 2.9-49.6 higher probability to present the mutated allele than those killed by acaricide treatment (P<0.05). In the in vivo trial, the mixtures containing cypermethrin+PBO (80.6-97.3%), and cypermethrin+amitraz (87.0-89.7%) were more efficacious than cypermethrin alone (76.3-80.5%). The highest level of efficacy was obtained with the mixture of cypermethrin+amitraz+PBO, which yielded >95% control that persisted for 28 days post-treatment against R. microplus infesting cattle when tested under field conditions in the Mexican tropics. Although this mixture is a potentially useful tool to combat pyrethroid resistance, a product based on an acaricide mixture like the one tested in this study has to be used rationally.

A sero-epidemiological survey of Chinese Babesia motasi for small ruminants in China

Babesia motasi BQ1 (Lintan) was first isolated from Haemaphysalis qinghaiensis collected in Gannan Tibet Autonomous Region, Gansu province in April 2000. In this study, a total of 3,204 serum samples from small ruminants in 22 provinces located in different districts of China were tested for antibodies against merozoite antigens from cultured B. motasi BQ1 (Lintan) by enzyme-linked immunosorbent assay. This method can survey the prevalence of low-pathogenic Chinese B. motasi. The results of this survey indicated that the average positive rate was 43.5 %, and the positive rates of investigated provinces were significantly different from 6.1 to 91.0 %, and the infections had been found in all provinces investigated. Our data provide large important information regarding the current sero-prevalence of B. motasi in China.

Glial cell line-derived neurotrophic factor is a key neurotrophin in the postnatal enteric nervous system

BACKGROUND

The enteric nervous system (ENS) continues its structural and functional growth after birth, with formation of ganglia and the innervation of growing smooth muscle. However, little is known about factors in the postnatal intestine that influence these processes.

METHODS

We examined the presence and potential role of glial cell line-derived nerve growth factor (GDNF) in the rat postnatal ENS using neonatal tissue, primary co-cultures of the myenteric plexus, smooth muscle, and glial cells as well as cell lines of smooth muscle or glial cells.

KEY RESULTS

Western blot analysis showed that GDNF and its co-receptors rearranged during transfection (RET) and GDNF family receptor alpha-1 were expressed in the muscle layer of the neonatal and adult rat intestine. Immunohistochemistry localized the receptors for GDNF to myenteric neurons, while GDNF was localized to smooth muscle cells. In a co-culture model, GDNF but not nerve growth factor, brain derived neurotrophic factor or neurotrophin-3 significantly increased neuronal survival and more than doubled the numbers of neurites in vitro. RT-PCR, qPCR, Western blotting, ELISA, and immunocytochemistry as well as bioassays of neuronal survival and of RET phosphorylation all identified intestinal smooth muscle as the source of GDNF in vitro. GDNF also induced morphological changes in the structure and organization of neurons and axons, causing marked aggregation of neuronal cell bodies and collinear development of axons. As well, GDNF (50-150 ng mL(-1)) significantly increased [(3)H]-choline uptake and stimulated [(3)H]-acetylcholine release.

CONCLUSIONS & INFERENCES

We conclude that GDNF derived from intestinal smooth muscle cells is a key factor influencing the structural and functional development of postnatal myenteric neurons.

High levels of insecticide resistance in introduced horn fly (Diptera: Muscidae) populations and implications for management

The horn fly, Haematobia irritans (L.) (Diptera: Muscidae), was introduced to Chile in the beginning of the 1990s. Since its introduction, farmers have controlled this pest almost exclusively with insecticides. To understand the consequences of different control strategies on the development of insecticide resistance and their persistence, a field survey was conducted at eight farms in the south of Chile to characterize insecticide resistance in field populations and resistance mechanisms. Horn fly samples were assayed to determine levels of resistance to pyrethroids and diazinon, genotyped for kdr and HialphaE7 mutations, and tested for general esterase activity. All field populations, including ones that were not treated with insecticides for the past 5 yr, showed high levels of cypermethrin resistance and high frequencies of the kdr mutation. None of the fly populations demonstrated resistance to diazinon and the HialphaE7 mutation was not detected in any of the fly samples. Esterase activities in all populations were comparable to those found in the susceptible reference strain. The findings of high frequencies of homozygous resistant and heterozygous individuals both in insecticide treated horn fly populations and in the untreated fly populations suggests complex interactions among field populations of the horn fly in Chile.