Derivation of a Focused, Brief Concussion Physical Examination for Adolescents With Sport-Related Concussion.

OBJECTIVE: To describe the derivation of a brief but pertinent physical examination (PE) for adolescents who have sustained sport-related concussion (SRC). DESIGN: Prospective cohort. SETTING: University concussion management clinic. PARTICIPANTS: Acutely concussed (AC, n = 52, 15.5 ± 1.4 years, 4.4 ± 2 days since injury, 26.2 ± 38 days to recovery, 71% males) and healthy control (HC) adolescents (n = 30, 15.8 ± 1.4 years, 73% males). INTERVENTION: Acutely concussed had a PE on visit 1 and were retested at visit 2 (13.6 ± 1 day after visit 1). Acutely concussed were further characterized as normal recovery (NR, n = 41, 15.5 ± 1.5 years, recovery time 13.0 ± 7 days) and delayed recovery (DR, n = 11, 15.5 ± 1.2 years, recovery time 75.4 ± 63 days). MAIN OUTCOME MEASURE: Physical examination findings, including cervical, vestibular, and oculomotor systems. RESULTS: Visit 1 abnormal PE signs were significantly greater in AC versus HC (2.79 ± 2.13 vs 0.07 ± 0.37, P < 0.0001) but not in NR versus DR (2.61 ± 2.2 vs 3.45 ± 1.8, P = 0.246). Visit 2 abnormal PE signs differentiated NR versus DR (0.17 ± 0.7 vs 2.45 ± 2.1, P < 0.0001). CONCLUSIONS: A brief focused PE can help to diagnose SRC, establish recovery, and may have prognostic value.

Substance use identification and follow-up rates among commercial and Medicare health insurance members in primary care and other settings.

BACKGROUND: The objective of this study was to investigate factors associated with substance use disorder identification and follow-up rates among samples of members of a private health insurance plan. METHODS: In an observational study, samples of claims data for 2017 for Commercial and Medicare members from a private health insurer were accessed and analyzed using descriptive statistics, decision tree analysis, and linear regression models. RESULTS: Commercial and Medicare members differed in age. Medicare members had higher rates of inclusion in a measure of substance use disorder than Commercial members, lower rates of initial short term follow-up, more opioid prescriptions from primary care provides, fewer prescriptions for opioid treatment, and higher rates of selected comorbid conditions. Mental health diagnoses and substance use disorder co-occurred frequently and to a greater extent in the Medicare sample. Among commercial members, there were primarily alcohol problems that increased with age, while opioid problems at about 10% peaked in the mid-twenties. More males were included among all substance types. The overall rate for an initial short term follow-up visit indicating initiation of treatment was 30%. There were large differences in the follow-up rates across settings with a very low rate (4.6% for alcohol and 6.9% for opioid) in primary care settings. CONCLUSIONS: These results suggest that increased attention in primary care to young adult males and to older adults, may help to reduce substance use disorder rates, especially alcohol use disorders.

A preliminary investigation of cognitive intolerance and neuroimaging among adolescents returning to school after concussion.

PRIMARY OBJECTIVE: To introduce the concept of cognitive intolerance. A test is proposed to measure this concept and pilot data are presented to support this measure and future research to develop this concept into a construct. Research design: Three-group comparison to protect larger study blinding. Methods and procedures: Two groups of student athletes (n = 13, n = 13) between 13 and 17 (mean 15.1 ± 1.1 years; 58% male) who sustained a sport-related concussion within 10 days and one group (n = 13) of age-matched healthy controls were recruited for a comparison of correlations between self and observer ratings of cognitive difficulties and DTI fractional anisotropy (FA) using tract-based spatial statistics (TBSS) analysis at two time points. Main outcomes and results: Significant negative only associations (higher cognitive difficulty and lower FA) with DTI FA were found in white matter tracts. These included the anterior corpus callosum, frontal-parietal longitudinal fasciculi, and cortical-subcortical pathways at only the second time point. Several working memory networks would likely involve connections using the above-identified white matter tracts. Conclusions: Cognitive intolerance can be defined as symptom exacerbation from prolonged cognitive activity. Cognitive intolerance could be measured by the n-back working memory task and time to symptom exacerbation.

Integrating Neuropsychology Services in a Multidisciplinary Concussion Clinic.

OBJECTIVE: To describe the integration of neuropsychology services in a multidisciplinary concussion clinic and provide descriptive information on patients, services, and initial health status. SETTING: A university-based outpatient sports medicine concussion clinic. PARTICIPANTS: A consecutive sample of 338 patients ages 8 to 84 years (median 23.5 years, 35% 13-18 years), 49.1% male, seen between 2014 and 2018. Patients' injuries included sports 42%, work 28.4%, and vehicular 12.1% and 48.5% were students. DESIGN: Descriptive statistics with group comparisons. MAIN MEASURES: 12-Item Short Form Health Survey (SF-12) T scores (mean = 50, SD = 10) referenced to US population. RESULTS: Half of the patients were seen within 24 days of their injury and showed reduced physical functioning (40.2) and average mental (emotional) functioning (48.8). Patients seen after 24 days showed even more reduced physical functioning (33.9) and reduced mental functioning (41.0), both P < .0001. Average treatment time was also longer, 88.1 (173.9) versus 186.8 (211.1) days, P < .0001. Two-thirds of patients were referred for cervical or vestibular physical therapy at their initial visit. CONCLUSION: Early referral for specialized care, including neuropsychology services, may be beneficial.

Evaluation of Executive Function and Mental Health in Retired Contact Sport Athletes.

OBJECTIVE: To compare retired professional contact sport athletes with age-matched noncontact sport athletes on measures of executive function and mental health. SETTING: The University Concussion Management Clinic. PARTICIPANTS: Twenty-one retired National Football League (NFL) and National Hockey League (NHL) players (mean age 56 years) and 21 age-matched noncontact sport athlete controls. DESIGNS: Case control. MAIN MEASURE: The self- and informant-reported Behavior Rating Inventory of Executive Function-Adult form (BRIEF-A); Wisconsin Card Sorting Test; Delis-Kaplan Executive Function System; Trail Making Part A and B; Wechsler Adult Intelligence Scale; Neuropsychological Assessment Battery; List Learning; Controlled Oral Word Association Test; Beck Depression Inventory; Beck Anxiety Inventory; and Personality Inventory of the DSM-5. RESULTS: Former NFL and NHL players perceived themselves to have some impairment in 2 of the 9 domains of executive function on the BRIEF-A; however, their informants reported no difference when compared with informants of noncontact athletes. No significant differences were found when comparing contact sport athletes with noncontact athletes on objective neuropsychological testing. Contact sport athletes qualified as clinically anxious and had more "unusual beliefs and experiences," although they remained within with age-based norms. CONCLUSION: Participation in contact sports at the professional level may not lead to later-life executive dysfunction, as the popular media and some research currently suggest.

An Exploratory Study of Mild Cognitive Impairment of Retired Professional Contact Sport Athletes.

OBJECTIVE: To test the hypothesis that mild cognitive impairment (MCI) rates are higher among retired professional contact sport athletes than in noncontact athlete controls and compare history of contact sports with other MCI risk factors. SETTING: University Concussion Management Clinic. PARTICIPANTS: Twenty-one retired National Football League and National Hockey League players and 21 aged-matched noncontact athlete controls. DESIGNS: Case-control. MAIN MEASURES: Comprehensive criteria were used to assess MCI based on the following: Wisconsin Card Sorting Test, Delis-Kaplan Executive Function System; Trail Making Parts A and B; Wechsler Adult Intelligence Scale-Third Edition subtests; Neuropsychological Assessment Battery Memory Module List Learning, Story Learning, and Naming subtests; and Controlled Oral Word Association Test. The Wide Range Achievement Test was used as a proxy measure for IQ. Atherosclerotic cardiovascular disease risk factors were self-reported and blood cholesterol was measured. Depression was measured by the Beck Depression Inventory-II (BDI). RESULTS: Eight contact sport athletes (38%) and 3 noncontact athletes (14%) met MCI criteria (P = .083). Contact sport athletes' scores were significantly worse on Letter Fluency and List B Immediate Recall. Contact athletes were more obese, had more vascular risk factors, and had higher scores on the BDI than controls. CONCLUSION: Athletes with a history of playing professional contact sports had more vascular risk factors and higher depression scores. MCI rates were somewhat higher, though not significant.

Multimodal Imaging of Retired Professional Contact Sport Athletes Does Not Provide Evidence of Structural and Functional Brain Damage.

BACKGROUND: Long-term consequences of playing professional football and hockey on brain function and structural neuronal integrity are unknown. OBJECTIVES: To investigate multimodal metabolic and structural brain magnetic resonance imaging (MRI) differences in retired professional contact sport athletes compared with noncontact sport athletes. METHODS: Twenty-one male contact sport athletes and 21 age-matched noncontact sport athletes were scanned on a 3 tesla (3T) MRI using a multimodal imaging approach. The MRI outcomes included presence, number, and volume of focal white matter signal abnormalities, volumes of global and regional tissue-specific brain structures, diffusion-tensor imaging tract-based spatial statistics measures of mean diffusivity and fractional anisotropy, quantitative susceptibility mapping of deep gray matter, presence, number, and volume of cerebral microbleeds, MR spectroscopy N-acetyl-aspartate, glutamate, and glutamine concentrations relative to creatine and phosphor creatine of the corpus callosum, and perfusion-weighted imaging mean transit time, cerebral blood flow, and cerebral blood volume outcomes. Subjects were also classified as having mild cognitive impairment. RESULTS: No significant differences were found for structural or functional MRI measures between contact sport athletes and noncontact sport athletes. CONCLUSIONS: This multimodal imaging study did not show any microstructural, metabolic brain tissue injury differences in retired contact versus non-contact sport athletes.

A systematic review of criteria used to define recovery from sport-related concussion in youth athletes.

OBJECTIVE: The Concussion in Sport Group guidelines recommend a multifaceted approach to help clinicians make return to sport decisions. The purpose of this study was to identify the most common multifaceted measures used to define clinical recovery from sport-related concussion in young athletes (high school and/or college level) and to summarise existing knowledge of criteria used to make return to sport decisions. DESIGN: Systematic review. DATA SOURCES: The PubMed (MEDLINE), SPORTDiscus and Embase electronic databases were searched from 1 January 2000 to 1 March 2017 by three independent reviewers. ELIGIBILITY CRITERIA: Inclusion criteria: elementary, high school and college age groups, and a specific definition of clinical recovery that required two or more measures. EXCLUSION CRITERIA: review articles, articles using the same sample population, case studies, non-English language and those that used one measure only or did not specify the recovery measures used. STUDY QUALITY: Study quality was assessed using the Downs and Black Criteria. RESULTS: Of 2023 publications, 43 met inclusion criteria. Included articles reported the following measures of recovery: somatic symptom resolution or return to baseline (100%), cognitive recovery or return to baseline (86%), no exacerbation of symptoms on physical exertion (49%), normalisation of balance (30%), normal special physical examination (12%), successful return to school (5%), no exacerbation of symptoms with cognitive exertion (2%) and normalisation of cerebral blood flow (2%). Follow-up to validate the return to sport decision was reported in eight (19%) articles. Most studies were case-control or cohort (level of evidence 4) and had significant risk of bias. CONCLUSION: All studies of sport-related concussion use symptom reports to define recovery. A minority of studies used multiple measures of outcome or had clearly defined recovery criteria, the most common being a combination of a self-reported symptom checklist and a computerised neurocognitive test. Future studies ideally should define recovery a priori using objective physiological measures in addition to symptom reports.

Safety and Prognostic Utility of Provocative Exercise Testing in Acutely Concussed Adolescents: A Randomized Trial.

OBJECTIVE: To evaluate (1) systematic assessment of exercise tolerance in adolescents shortly after sport-related concussion (SRC) and (2) the prognostic utility of such assessment. DESIGN: Prospective randomized controlled trial. SETTING: University and community sports medicine centers. PARTICIPANTS: Adolescents with SRC (1-9 days from injury). Sixty-five were randomized and 54 completed the study (mean age 15 years, 4 days after injury). INTERVENTIONS: Buffalo Concussion Treadmill Test (BCTT, n = 27) or not (controls, n = 27) on visit day #1. Heart rate threshold (HRt) at symptom exacerbation represented level of exercise tolerance. Participants reported symptoms daily for 14 days and then had follow-up BCTT (n = 54). Recovery was defined as returning to normal level of symptoms and exercise tolerance, verified by independent physician examination. MAIN OUTCOME MEASURES: Days to recovery and typical (≤21 days) versus prolonged recovery (>21 days). Mixed effects linear models and linear regression techniques examined symptom reports and time to recovery. Linear regression assessed the association of HRt with recovery time. RESULTS: Days to recovery (P = 0.7060) and typical versus prolonged recovery (P = 0.1195) were not significantly different between groups. Symptom severity scores decreased in both groups over 14 days (P < 0.0001), were similar (P = 0.2984), and did not significantly increase the day after the BCTT (P = 0.1960). Lower HRt on visit day #1 was strongly associated with prolonged recovery time (P = 0.0032). CONCLUSIONS: Systematic evaluation of exercise tolerance using the BCTT within 1 week after SRC did not affect recovery. The degree of early exercise intolerance after SRC was important for prognosis. This has implications for school academic and team preparation.

Brain or strain? Symptoms alone do not distinguish physiologic concussion from cervical/vestibular injury.

OBJECTIVE: To compare symptoms in patients with physiologic postconcussion disorder (PCD) versus cervicogenic/vestibular PCD. We hypothesized that most symptoms would not be equivalent. In particular, we hypothesized that cognitive symptoms would be more often associated with physiologic PCD. DESIGN: Retrospective review of symptom reports from patients who completed a 22-item symptom questionnaire. SETTING: University-based concussion clinic. PATIENTS: Convenience sample of 128 patients who had symptoms after head injury for more than 3 weeks and who had provocative treadmill exercise testing. INDEPENDENT VARIABLES: Subjects were classified as either physiologic PCD (abnormal treadmill performance and a normal cervical/vestibular physical examination) or cervicogenic/vestibular PCD (CGV, normal treadmill performance, and an abnormal cervical/vestibular physical examination). MAIN OUTCOME MEASURES: Self-reported symptoms. Univariate and multivariate methods, including t tests, tests of equivalence, a logistic regression model, k-nearest neighbor analysis, multidimensional scaling, and principle components analysis were used to see whether symptoms could distinguish PCD from CGV. RESULTS: None of the statistical methods used to analyze self-reported symptoms was able to adequately distinguish patients with PCD from patients with CGV. CONCLUSIONS: Symptoms after head injury, including cognitive symptoms, have traditionally been ascribed to brain injury, but they do not reliably discriminate between physiologic PCD and cervicogenic/vestibular PCD. Clinicians should consider specific testing of exercise tolerance and perform a physical examination of the cervical spine and the vestibular/ocular systems to determine the etiology of postconcussion symptoms. CLINICAL RELEVANCE: Symptoms after head injury, including cognitive symptoms, do not discriminate between concussion and cervical/vestibular injury.

Evaluation of the Zurich Guidelines and exercise testing for return to play in adolescents following concussion.

OBJECTIVE: To evaluate return to play (RTP) and return to classroom outcomes when the Zurich guidelines are combined with a standardized exercise treadmill test [Buffalo Concussion Treadmill Test (BCTT)] and computerized neuropsychological (cNP) testing in adolescent athletes after concussion. DESIGN: Retrospective chart review and follow-up. SETTING: University Sports Medicine Concussion Clinic. PARTICIPANTS: One hundred seventeen athletes (75% male) with sport concussion ages 13 to 19 years and telephone follow-up of 91 (77.8%) athletes and their parents. INTERVENTIONS: Concussed athletes who were asymptomatic at rest completed Automated Neuropsychological Assessment Metrics or Immediate Post-concussion Assessment and Cognitive Test cNP testing followed by the BCTT on the same day. Athletes then followed the Zurich consensus guidelines for RTP. MAIN OUTCOME MEASURES: The primary outcome measure was the degree of success in RTP, that is, RTP with or without return of concussive symptoms. Secondary outcome measure was return to school with or without symptoms. RESULTS: All athletes returned to sport without exacerbation of symptoms. Telephone follow-up revealed that 38.5% experienced new issues upon return to the classroom. Forty-eight percent of athletes had 1 or more cNP subtests below average (

Correlation of cognition and SPECT perfusion: easy Z score and SPM analysis of a pilot sample with cerebral small vessel disease.

BACKGROUND/AIMS: To associate neuropsychology test performance with perfusion on single-photon emission computed tomography (SPECT) among 12 patients with cerebral small vessel disease. METHODS: The easy Z score imaging system (eZIS) was used to compare patient images to those of normal controls. Scores from neuropsychological tests commonly used to screen for dementia were associated with SPECT resting perfusion image values using the statistical parametric mapping (SPM) program. RESULTS: Immediate Memory and Delayed Memory index scores, as well as memory subtests of the Repeatable Battery for Assessment of Neuropsychological Status showed cluster- and voxelwise positive correlations with hypoperfusion in frontal, temporal and cerebellar regions. Negative correlations, primarily in frontal regions, were interpreted as compensatory hyperperfusion. CONCLUSION: eZIS and SPM analyses of SPECT images showed perfusion correlations with neuropsychological tests with small vessel disease.

Exercise treatment for postconcussion syndrome: a pilot study of changes in functional magnetic resonance imaging activation, physiology, and symptoms.

PURPOSE: To compare functional magnetic resonance imaging (fMRI) activation patterns during a cognitive task, exercise capacity, and symptoms in postconcussion syndrome (PCS) patients who received exercise treatment (n = 4) with a PCS placebo stretching group (n = 4) and a healthy control group (n = 4). METHODS: Subjects completed a math processing task during fMRI and an exercise treadmill test before (time 1) and after approximately 12 weeks (time 2). Exercise subjects performed aerobic exercise at 80% of the heart rate (HR) attained on the treadmill test, 20 minutes per day with an HR monitor at home, 6 days per week. The program was modified as the HR for symptom exacerbation increased. RESULTS: At time 1, there was no difference in fMRI activation between the 2 PCS groups but healthy controls had significantly greater activation in the posterior cingulate gyrus, lingual gyrus, and cerebellum versus all PCS subjects (P < .05, corrected for multiple comparisons). At time 2, exercise PCS did not differ from healthy controls whereas placebo stretching PCS had significantly less activity in the cerebellum (P < .05 corrected) and in the anterior cingulate gyrus and thalamus (P < .001, uncorrected) versus healthy controls. At time 2, exercise PCS achieved a significantly greater exercise HR (P < .001) and had fewer symptoms (P < .0004) than placebo stretching PCS. Cognitive performance did not differ by group or time. CONCLUSIONS: Controlled aerobic exercise rehabilitation may help restore normal cerebral blood flow regulation, as indicated by fMRI activation, in PCS patients. The PCS symptoms may be related to abnormal cerebral blood flow regulation.

Testing General Relativity with Low-Frequency, Space-Based Gravitational-Wave Detectors.

We review the tests of general relativity that will become possible with space-based gravitational-wave detectors operating in the ∼ 10-5 - 1 Hz low-frequency band. The fundamental aspects of gravitation that can be tested include the presence of additional gravitational fields other than the metric; the number and tensorial nature of gravitational-wave polarization states; the velocity of propagation of gravitational waves; the binding energy and gravitational-wave radiation of binaries, and therefore the time evolution of binary inspirals; the strength and shape of the waves emitted from binary mergers and ringdowns; the true nature of astrophysical black holes; and much more. The strength of this science alone calls for the swift implementation of a space-based detector; the remarkable richness of astrophysics, astronomy, and cosmology in the low-frequency gravitational-wave band make the case even stronger.

Comparison of atom interferometers and light interferometers as space-based gravitational wave detectors.

We consider a class of proposed gravitational-wave detectors based on multiple atomic interferometers separated by large baselines and referenced by common laser systems. We compute the sensitivity limits of these detectors due to intrinsic phase noise of the light sources, noninertial motion of the light sources, and atomic shot noise and compare them to sensitivity limits for traditional light interferometers. We find that atom interferometers and light interferometers are limited in a nearly identical way by intrinsic phase noise and that both require similar mitigation strategies (e.g., multiple-arm instruments) to reach interesting sensitivities. The sensitivity limit from motion of the light sources is slightly different and, in principle, favors the atom interferometers in the low-frequency limit, although the limit in both cases is severe.

Intentional versus unintentional contact as a mechanism of injury in youth ice hockey.

BACKGROUND: Youth ice hockey injury rates and mechanisms have been described by various classification systems. Intentional versus unintentional contact was used to classify mechanisms of injuries. All injuries (n=247) in one youth hockey programme over a 5-year period were recorded and included in the analysis. PURPOSE: To evaluate youth ice hockey injuries and compare programmes that allow body checking versus programmes that do not allow body checking. A primary goal was to determine whether programmes that allow body checking have increased injury rates from intentional body contact. Another goal was to describe the rates of injury across ages, levels of competitive play and during games versus practices. METHODS: Rates of injury were compared for three levels of competition (house, select and representative) for approximately 3000 boys aged 4-18 years over a 5-year period. This represents 13 292 player years. Data were collected prospectively in this cohort study. All injuries were reported prospectively by a designated team official and verified by a physician. The log injury rate (per 1000 player hours) was modelled via Poisson regression with log player hours used as an offset. Rate ratio was used to explain the covariate-adjusted injury rate for each of three groups (all injuries, intentional injuries, unintentional injuries). RESULTS: Unintentional contacts accounted for 66.0% of overall injuries (95% CI 60.0 to 72.0), compared with 34.0% from intentional contacts (p<0.001; Z=5.25). Serious injuries (fractures, dislocations, concussions) resulted more often from unintentional collisions (p=0.04). Players in more competitive leagues that allow body checking had a greater incidence of total injuries than less competitive leagues. CONCLUSIONS: Most injuries in the youth hockey programme studied were the result of unintentional contact, and were generally more severe. These findings were not expected given previously published research.

Reliability of a graded exercise test for assessing recovery from concussion.

OBJECTIVE: To evaluate a graded treadmill test for retest reliability (RTR) and interrater reliability (IRR) in the evaluation of the physiologic effects of symptom exacerbation from concussion. DESIGN: Prospective case series (RTR) and blinded rater assessment of 10 actors portraying patients with and without symptom exacerbation (IRR). SETTING: University Sports Medicine Concussion Clinic. PARTICIPANTS: For RTR, 21 refractory concussed patients (11 athletes and 10 nonathletes) and 10 healthy subjects; for IRR, 32 raters representing a variety of health care disciplines. INTERVENTION: For RTR, a Balke protocol treadmill test to symptom exacerbation before and after 2 to 3 weeks. For IRR, video recordings of actors during the treadmill test viewed by raters blinded to condition. MAIN OUTCOME MEASURES: For RTR, agreement of the tests for maximal heart rate (HR), systolic blood pressure, diastolic blood pressure, and rating of perceived exertion. For IRR, presence or absence of symptom exacerbation and the symptom exacerbation HR. RESULTS: Raters achieved a sensitivity of 99% for identifying actors with symptom exacerbation and a specificity of 89% for ruling out concussion symptoms and agreed on 304 of 320 observations (accuracy of 95%). The intraclass correlation coefficient for the symptom exacerbation HR was large at 0.90 (95% confidence interval, 0.78-0.98). The treadmill test had good RTR for maximum HR (intraclass correlation coefficient, 0.79) but not for systolic blood pressure, diastolic blood pressure, or rating of perceived exertion. CONCLUSIONS: The Balke exercise treadmill protocol has very good IRR and sufficient RTR for identifying patients with symptom exacerbation from concussion.

A Physiological Approach to Prolonged Recovery From Sport-Related Concussion.

Management of the athlete with postconcussion syndrome (PCS) is challenging because of the nonspecificity of PCS symptoms. Ongoing symptoms reflect prolonged concussion pathophysiology or conditions such as migraine headaches, depression or anxiety, chronic pain, cervical injury, visual dysfunction, vestibular dysfunction, or some combination of these. In this paper, we focus on the physiological signs of concussion to help narrow the differential diagnosis of PCS in athletes. The physiological effects of exercise on concussion are especially important for athletes. Some athletes with PCS have exercise intolerance that may result from altered control of cerebral blood flow. Systematic evaluation of exercise tolerance combined with a physical examination of the neurologic, visual, cervical, and vestibular systems can in many cases identify one or more treatable postconcussion disorders.

Prompt Electromagnetic Transients from Binary Black Hole Mergers.

Binary black hole (BBH) mergers provide a prime source for current and future interferometric GW observatories. Massive BBH mergers may often take place in plasma-rich environments, leading to the exciting possibility of a concurrent electromagnetic (EM) signal observable by traditional astronomical facilities. However, many critical questions about the generation of such counterparts remain unanswered. We explore mechanisms that may drive EM counterparts with magnetohydro-dynamic simulations treating a range of scenarios involving equal-mass black-hole binaries immersed in an initially homogeneous fluid with uniform, orbitally aligned magnetic fields. We find that the time development of Poynting luminosity, which may drive jet-like emissions, is relatively insensitive to aspects of the initial configuration. In particular, over a significant range of initial values, the central magnetic field strength is effectively regulated by the gas flow to yield a Poynting luminosity of 1045 - 1046 ρ -13 M 8 2 ergs-1, with BBH mass scaled to M 8 ≡ M/(108 M ⨀) and ambient density ρ -13 ≡ ρ/(10-13 g cm-3). We also calculate the direct plasma synchrotron emissions processed through geodesic ray-tracing. Despite lensing effects and dynamics, we find the observed synchrotron flux varies little leading up to merger.

Concussion management knowledge among residents and students and how to improve it.

AIM: Recognition and management of concussion is an area of growing importance. The objective was to measure concussion knowledge among residents and medical students (MS). METHODS: Baseline knowledge was assessed by a standardized questionnaire. Control group (family medicine [FM], pediatric medicine [PM] and emergency medicine) residents were given reading material, and intervention group rotated in a clinic (sports medicine residents and MS). Subjects were retested after 36.82 (16.1) days. Pre- and post-intervention test scores were compared. RESULTS: The average baseline knowledge scores were 79.2% for emergency medicine residents, 61.4% for FM, 68.5% for PM, 71.7% for sports medicine residents and 68.0% for MS. Knowledge increase for control group was 1.16% compared with 14.41% for the clinical rotation group (p < 0.0001). CONCLUSION: PM and FM residents can benefit from more focused education about concussion.