bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of prior concussion and contact sport participation on the brain
Authors: Churchill Nathan , Hutchison Michael , Schweizer Tom A 
Published: November 2017

Objectivethere is currently limited information on the neurobiological effects of contact sport participation, and interactions with history of concussion. The goal of this study is to examine the interactions between history of concussion and contact sport participation, using biomarkers of cerebral metabolites, brain function, and white matter microstructure.Designcross-sectional study.Settingsport medicine clinic, affiliated with inter-university sport program (secondary care).Participants43 athletes without concussion in the past 6 months were recruited, including 22 athletes without prior concussion (13 non-contact, 9 contact; 11 female) and 21 athletes with a history of concussion (13 non-contact, 8 contact; 11 female).Outcome measuresMagnetic Resonance Imaging (MRI) was used to measure brain biomarkers: MRI spectroscopy to evaluate cerebral metabolites; functional MRI to assess brain function; diffusion tensor imaging for white matter microstructure.Main resultsathletes in contact sports with prior concussion showed significant differences in brain structure and function, relative to athletes in non-contact sports, and those in contact sports without prior injury. This included significantly elevated glutamate ratios, decreased functional connectivity of the visual and motor systems, and increased fractional anisotropy of white matter.ConclusionsThis study provides the first multi-modal MRI data showing altered brain structure and function in athletes with a history of concussion and interactions with contact sport participation. These findings provide strong preliminary evidence that athletes in contact sports may be more vulnerable to the long-term effects of sport concussion.Competing interestsNone.
Attention problems as a risk factor for concussion in youth ice-hockey players
Authors: Gerschman Tommy , Schneider Kathryn , Yeates Keith , Brooks Brian L , Kipps Courtney , Emery Carolyn 
Published: November 2017

ObjectiveTo examine attention problems in youth ice-hockey players as a risk factor for concussion.DesignSecondary analysis of two prospective cohort studies.SettingIce-rinks and Sport Medicine Centres in two Canadian cities over three ice-hockey seasons (2011/12, 2012/13, 2014/15).Assessment of risk factorsSelf-report of formal diagnosis of attention or learning disorders were collected on previously validated preseason baseline questionnaires by all participating players. Parents and players completed the Behaviour Assessment System for Children (BASC-2), which includes inattention and hyperactivity scales.Participants2,364 Canadian ice-hockey players (11–17 years old, 87% male).Outcome measuresA previously validated prospective injury surveillance system was used. All suspected concussions were referred to the study physician for confirmation of diagnosis. Concussion risk ratios (RR) were estimated, including stratification by known risk factors.ResultsOne-hundred ninety-two of 2,215 players (9%) self-reported attention and/or learning disorders at baseline. Overall, 256 players (11%) sustained one or more concussions during a season. Players identified as “at-risk” for attention-deficit hyperactivity disorder (ADHD), based on BASC-2 T-scores (inattention and/or hyperactivity scale) greater than 60, had a greater risk of concussion during the season based on child report [RR=1.51 (95% CI 1.13–2.04)] and parent report [2.97 (95% CI 1.65–5.34)]. In players with no history of previous concussion, the RR based on child report was 1.88 (95% CI 1.22–2.90) and based on parent report was 5.03 (95% CI 2.45–10.29).ConclusionsIce-hockey players identified as “at-risk” for ADHD on the basis of baseline BASC-2 scores are at a greater risk of concussion.Competing interestsNone.
Baseline symptoms are associated with post-concussion symptom frequency and severity in college and high school athletes
Authors: Teel EF , Wasserman EB , Register-Mihalik JK , Mihalik JP 
Published: November 2017

ObjectiveTo determine the association between baseline symptoms and symptom frequency and severity one day post-concussion in college and high school athletes.DesignProspective cohort.SettingUSA colleges (n=26) and high schools (n=210).SubjectsConcussed individuals (n=375; 314 males; 61 females) recruited from a baseline cohort (N=8,905).InterventionBaseline presence or absence for each of the 20 items on a Graded Symptom Checklist (GSC).Outcome measuresGSC symptom frequency and severity one day post-concussion.ResultsIndividuals with baseline headache (χ2(1)=10.98;P<0.001), fatigue (χ2(1)=6.06;P=0.014), sleeping more than usual (χ2(1)=16.90;P<0.001), blurred vision (χ2(1)=20.48;P<0.001), light/noise sensitivity (χ2(1)=4.67;P=0.031), and mental fogginess (χ2(1)=6.08;P=0.014) reported these symptoms at a higher frequency post-concussion. Subjects reporting the following baseline symptoms had greater severity of the same symptom post-concussion: headache (Presence: median=2; IQR=1–4; Absence: median=2, IQR=0–3;P=0.004), fatigue (Presence: median=1; IQR=0–3; Absence: median=0, IQR=0–2;P=0.017), sleeping more than usual (Presence: median=1, IQR=0–3; Absence: median=0, IQR=0–0;P<0.001), blurred vision (Presence: median=1; IQR=0–2; Absence: median=0, IQR=0–0;P<0.001), sensitivity to light and noise (Presence: median=1, IQR=0–3; Absence: median=0, IQR=0–1;P=0.010), and fogginess (Presence: median=2, IQR=0–3; Absence: median=0, IQR=0–1;P=0.002). No other symptoms at baseline were associated with post-concussion symptom frequency or severity (P>0.05).ConclusionsAthletes reporting baseline symptoms, particularly those in physical and sleep-related domains, were more likely to report a higher frequency and severity of these same symptoms one day post-concussion. Understanding factors influencing post-concussion symptom recovery may inform clinical decision-making and offer selection criteria for appropriate active recovery strategies.Competing interestsNone.
Correlates to concussion recovery in college athletes: prospective evaluation of pre-injury modifiers and post-injury clinical and neuropsychological assessments
Authors: Putukian Margot , Kaitlin Riegler , Stephanie Amalfe , Ruben Echemendia , Frisina Pasquale G. 
Published: November 2017

Objectivevaluate relationships among pre-injury modifiers and post-injury assessments on sport-related concussion (SRC) recovery.DesignProspective-correlational.SettingSingle University.Participants208 SRCs; 173 athletes (males=132, females=41).Assessment of risk factorsBaseline modified sideline concussion assessment tool (m-SCAT):symptom checklist, Standardised Assessment of Concussion (SAC), modified-Balance Error Scoring System (m-BESS), Generalised Anxiety Disorder scale (GAD-7), Patient Health Questionnaire (PHQ-9), and history of concussion, learning disorder (LD), headaches/migraines, and depression/anxiety. m-SCAT and hybrid neuropsychological tests 48-hours post-injuryOutcome measuresDays to symptom free (DSF) and return to full play (DFP).Main resultsExpected concussion modifiers, (gender, prior concussion, LD, headaches/migraines, depression/anxiety, PHQ-9 or GAD-7) were NOT significantly associated with DSF or DFP (p >.05). Although males (M=9.83, SD=12.22) became SF sooner (1.75 days) than females (M=11.58, SD=9.79), Mann-Whitney test indicated that differences for gender were not statistically significant, U=1249, p=0.11 and males (M=21.20,SD=20.75) and females (M=17.33, SD=14.86) didn’t differ significantly on DFP, U=613, p=0.25. ≤48-hours m-SCAT performance Athletes reporting more symptoms and higher symptom-severity score, took more DSF (rs=0.32, p<0.01, rs=0.35, p<0.01, respectively) and DFP (rs=0.19, p<0.05, rs=0.20, p<0.05, respectively). No statistically significant relationship between SAC or m-BESS and recovery existed. Four symptoms positively and significantly correlated with number of DSF and DFP: headache (SF:rs=0.27, p<0.01; FP:rs=0.23, p<0.05), neck-pain (SF:rs=0.36, p<0.05; FP, rs=0.38, p<0.05), feeling slowed down (SF:rs=0.21, p<0.01; FP:rs=0.19, p<0.05), and nervous/anxious (SF:rs=0.28, p<0.01; FP:rs=0.21, p<0.05). Athletes with slower RT on ImPACT took more DSF (rs=0.27, p<0.01) and DFP (rs=0.25, p<0.01). Athletes scoring lower/worse on ImPACT visual-motor speed composite had higher DSF (rs=-0.24, p<0.01) and DFP (rs=-0.35, p<0.01).ConclusionsWhile pre-injury “modifiers” aren’t correlated with clinical recovery, acute assessments after SRC may indicate prolonged recovery.Competing interestsNone.
Effect of sub-concussive impacts sustained throughout a contact-sport season on quiet stance centre of pressure
Authors: Smirl Jonathan D , Dierijck Jill K , Wright Alexander D , Bryk Kelsey , Donkelaar Paul van 
Published: November 2017

ObjectiveTo examine how sub-concussive head trauma throughout a contact-sport season affects quiet stance centre of pressure (COP) swayDesignProspective cohortSettingLaboratoryParticipants: Twenty-four elite male football players (age range 18–22) were recruited for the studyInterventionQuiet stance data was collected at the start and at the end of the competitive season. One-minute trials were performed with eyes-open and eyes-closed on a force plate (NDI True Impulse) with feet hip-width apart and hands-on-hips. Biomechanical head-impact exposure was indexed using the xPatch (X2 Biosystems)Outcome measuresCOP measures: Anterior/posterior (AP) and medial/lateral (ML) root-mean-square displacement (RMSd) and mean velocity. Biomechanical head-impact data: For hits above 20g, peak linear acceleration (PLA), and peak rotational acceleration (PRAwere estimated across the competitive season. Independent variables included time (2) and condition (2)ResultsRM-ANOVA reveal an effect of condition (eyes-open vs eyes-closed) in AP-RMSd (p=0.035, 95% CI: 0.006, 0.159), ML-RMSd (p<0.0001, CI: 0.083, 0.250), and ML mean velocity (p<0.0001, 95% CI: 0.111, 0.308). However, despite exposure to a cumulative 8147.2±6215.5 g in linear acceleration and 34.5 x 106 ± 59.0x106 rad/s2 in rotational acceleration, there were no significant differences between conditions for COP measures at post-seasonConclusionsIn contrast to the prolonged COP alterations observed following acute concussions, there were no discernable effects of sub-concussive trauma on COP sway during quiet stance in the same population. This is an important finding as it reveals that participation in contract-sport does not impair quiet stance balanceCompeting interestsNone.
Epidemiology of athletic trainer services for concussions among us high school student-athletes
Authors: Wasserman Erin B , Kerr Zachary Y , Dompier Thomas P 
Published: November 2017

ObjectiveThis study examined athletic trainer (AT) services for sports-related concussion among high school (HS) student-athletes during the 2011/12–2013/14 academic years.DesignDescriptive epidemiology.SettingConcussion data originated from the National Athletic Trainers Injury and Outcomes Network (NATION), a US-wide surveillance program comprised of a convenience sample of 127 HS. All concussions were diagnosed and reported by ATs.ParticipantsOur sample included 1662 concussions with service data among HS student-athletes from 22 sports; 48.0% were in football; 8.2% were recurrent. Of 607 concussions in sex-comparable sports, 52.7% were among females.Assessment of risk factorsWe examined outcome measures by sport (American football vs. non-football), sex, and whether the concussion was reported as recurrent.Outcome measuresATs reported the number and types of AT room visits and services. We compared the means of these measures by sport, sex, and recurrence using independent samples t-tests.Main resultsThere were 15,698 AT room visits reported (mean=9.5 per concussion; Standard Deviation [SD]=7.4). ATs provided an average 1.2 (SD=0.3) services per visit. No differences existed by sport or recurrence. In sex-comparable sports, females had a mean 12.2 (SD=10.5) visits compared to 9.5 (SD=7.0) among males (p<0.001). No sex differences existed in services per visit.ConclusionsThere are more AT room visits per concussion among females than males in sex-comparable sports. This is likely related to previous research finding symptom resolution time is longer in females than males. Identifying concussions that will require more AT services may help with resource allocation and planning for ATs.Competing interestsThis project was funded by the National Athletic Trainers’ Association Research and Education Foundation (NATAREF), and the Central Indiana Corporate Partnership (CICP) Foundation in cooperation with BioCrossroads. The content of this report is solely the responsibility of the authors and does not necessarily reflect the views of the NATAREF, CICP Foundation or BioCrossroads.
A graded exercise protocol with added cognitive load: a standardised approach for assessing symptom responses following a sports related concussion?
Authors: S John Sullivan , Alla Sridhar , Hale Leigh , Lee Hopin , McCrory Paul 
Published: November 2017

ObjectiveTo examine the self-reported concussion symptoms provoked with a controlled sub-maximal exercise protocol, incorporating a cognitive load, in athletes recovering from a sports-related concussion.DesignA three group repeated measures study with follow-up.SettingUniversity laboratory.ParticipantsUniversity aged athletes (12 males, 3 females) with a recent (<14 days) sports-related concussion and 30 (24 males and 6 females) matched recreationally active, non-concussed persons.InterventionThree groups: Concussed (Con), Control+exercise+cognitive load (CECL); and Control+exercise (CE) undertook a 19 min standardised sub-maximal progressive exercise protocol. The Con and CECL groups simultaneously completed a package of reaction time tasks (cognitive load).The Con group completed an identical protocol on a subsequent visit. Participants were instructed to “stop” the test any time they wished.Outcome measuresThe symptom severity score (SSS) obtained from the SCAT2 post-concussion symptom scale was determined prior to, immediately following, and 15 min aftercompleting the exercise protocol.Main resultsThe groups X time interaction (F4,84=31.9, p<001)indicated that the Con group was different from both control groups at all 3 time intervalswith differences between the time points for the Con group, but not for the others.Three members from the Con group did not complete the protocol. A significant visit X time interaction (F1,9=56.04) was seen for the Con group which completed the protocol on 2 occasions.ConclusionsThe protocoldifferentially provoked symptoms in recently concussed athletes suggesting its potential in standardising assessment procedures to inform return to play decisions.Competing interestsPaul McCrory is a co-investigator, collaborator, or consultant on grants relating to mild TBI funded by several governmental organisations. He is Co-Chair of the Australian Centre for Research into Sports Injury and its Prevention (ACRISP), supported by the IOC. He has been reimbursed by the government, professional scientific bodies, and sporting bodies for presenting research relating to mild TBI and sport-related concussion at meetings, scientific conferences, and symposiums. He received support since 2001 from CogState Inc for research costs and the development of educational material. He does not hold any individual shares in any company related to concussion or brain injury assessment or technology.None.
Acute sport-related concussion induces transient impairment in dynamic cerebral auto regulation that is related to scat3 performance
Authors: Wright Alexander D , Smirl Jonathan D , Bryk Kelsey , Fraser Sarah K , Grewal Harjas S , Jakovac Michael , Dierijck Jill , Donkelaar Paul van 
Published: November 2017

ObjectiveExamine how the frequency-dependent relationship between blood pressure (BP) and cerebral blood velocity (CBV) is affected by acute sport-related concussion.DesignProspective Cohort.SettingLaboratory.Participants:136 male contact-sport athletes (19.1±1.4 years) recruited, subset of 14 sustained concussions (19±1.4 years).InterventionParticipants completed baseline (T0) and post-injury testing at 72-hours (T1), 2-weeks (T2), and 1-month (T3). BP was monitored via finger photoplethysmography, and transcranial Doppler ultrasound indexed CBV in the middle cerebral artery. Squat-stand manoeuvers were performed at 0.05 and 0.10Hz to enhance BP variation. RM-ANOVA independent variables included time (4) and frequency (2).Outcome measuresTransfer function analysis point estimates quantified coherence (correlation), phase (synchronisation) and gain (amplitude buffer) metrics between BP and CBV waveforms.ResultsSignificant frequency-time interactions for phase (p=0.007) and gain (p=0.049). Simple effects analysis revealed time effects for phase at 0.10 Hz, indicating reductions at T1 (95% CI: 0.033 – 0.24 rads, p=0.008) and T2 (95% CI: 0.014–0.196 rads, p=0.02) compared to T0. On average, return-to-play occurred at T2 (median 14 days). Phase reductions at T1 were correlated with Standardised Assessment of Concussion performance (r=0.659, p=0.02).ConclusionsThese results reveal transient post-concussion impairments in the capacity of the cerebrovasculature to buffer BP oscillations, which exceeded clinical recovery duration. Phase reductions at 0.10Hz suggest the presence of a cerebrovascular autonomic dysregulation, which could leave the brain less protected to BP surges. This key finding may help explain why the brain is more vulnerable to additional trauma during the post-injury recovery period.Competing interestsNone.
What domains of clinical function should be assessed after sport-related concussion? A systematic review
Authors: Feddermann-Demont Nina , Echemendia Ruben J , Schneider Kathryn J , Solomon Gary S , Hayden K Alix , Turner Michael , Dvořák Jiří , Straumann Dominik , Tarnutzer Alexander A 
Published: November 2017

BackgroundSport-related concussion (SRC) is a clinical diagnosis made after a sport-related head trauma. Inconsistency exists regarding appropriate methods for assessing SRC, which focus largely on symptom-scores, neurocognitive functioning and postural stability.DesignSystematic literature review.Data sourcesMEDLINE, EMBASE, PsycINFO, Cochrane-DSR, Cochrane CRCT, CINAHL, SPORTDiscus (accessed July 9, 2016).Eligibility criteria for selecting studiesOriginal (prospective) studies reporting on postinjury assessment in a clinical setting and evaluation of diagnostic tools within 2 weeks after an SRC.ResultsForty-six studies covering 3284 athletes were included out of 2170 articles. Only the prospective studies were considered for final analysis (n=33; 2416 athletes). Concussion diagnosis was typically made on the sideline by an (certified) athletic trainer (55.0%), mainly on the basis of results from a symptom-based questionnaire. Clinical domains affected included cognitive, vestibular and headache/migraine. Headache, fatigue, difficulty concentrating and dizziness were the symptoms most frequently reported. Neurocognitive testing was used in 30/33 studies (90.9%), whereas balance was assessed in 9/33 studies (27.3%).Summary/conclusionsThe overall quality of the studies was considered low. The absence of an objective, gold standard criterion makes the accurate diagnosis of SRC challenging. Current approaches tend to emphasise cognition, symptom assessment and postural stability with less of a focus on other domains of functioning. We propose that the clinical assessment of SRC should be symptom based and interdisciplinary. Whenever possible, the SRC assessment should incorporate neurological, vestibular, ocular motor, visual, neurocognitive, psychological and cervical aspects.
Mortality in dementia with Lewy bodies compared with Alzheimer’s dementia: a retrospective naturalistic cohort study
Authors: Price Annabel , Farooq Redwan , Yuan Jin-Min , Menon Vandana B , Cardinal Rudolf N , O’Brien John T 
Published: November 2017

ObjectivesTo use routine clinical data to investigate survival in dementia with Lewy bodies (DLB) compared with Alzheimer’s dementia (AD). DLB is the second most common dementia subtype after AD, accounting for around 7% of dementia diagnoses in secondary care, though studies suggest that it is underdiagnosed by up to 50%. Most previous studies of DLB have been based on select research cohorts, so little is known about the outcome of the disease in routine healthcare settings.SettingCambridgeshire & Peterborough NHS Foundation Trust, a mental health trust providing secondary mental health care in England.Sample251 DLB and 222 AD identified from an anonymised database derived from electronic clinical case records across an 8-year period (2005–2012), with mortality data updated to May 2015.ResultsRaw (uncorrected) median survival was 3.72 years for DLB (95% CI 3.33 to 4.14) and 6.95 years for AD (95% CI 5.78 to 8.12). Controlling for age at diagnosis, comorbidity and antipsychotic prescribing the model predicted median survival for DLB was 3.3 years (95% CI 2.88 to 3.83) for males and 4.0 years (95% CI 3.55 to 5.00) for females, while median survival for AD was 6.7 years (95% CI 5.27 to 8.51) for males and 7.0 years (95% CI 5.92 to 8.73) for females.ConclusionSurvival from first presentation with cognitive impairment was markedly shorter in DLB compared with AD, independent of age, sex, physical comorbidity or antipsychotic prescribing. This finding, in one of the largest clinical cohorts of DLB cases assembled to date, adds to existing evidence for poorer survival for DLB versus AD. There is an urgent need for further research to understand possible mechanisms accounting for this finding.
Prognostic value of lymphocyte-to-monocyte ratio and neutrophil-to-lymphocyte ratio in follicular lymphoma: a retrospective cohort study
Authors: Lee Shing Fung , Luque-Fernandez Miguel Angel 
Published: November 2017

ObjectivesThe clinical course and prognosis of follicular lymphoma (FL) are diverse and associated with the patient’s immune response. We investigated the lymphocyte-to-monocyte ratio (LMR) and neutrophil-to-lymphocyte ratio (NLR) as prognostic factors in patients with FL, including those receiving radiotherapy.DesignA retrospective cohort study.SettingRegional cancer centre in Hong Kong.Participants88 patients with histologically proven FL diagnosed between 2000 and 2014.Materials and methodsThe best LMR and NLR cut-off values were determined using cross-validated areas under the receiver operating characteristic curves. The extent to which progression-free survival (PFS) and overall survival differed by NLR and LMR cut-off values was assessed using Kaplan-Meier analysis and log-rank tests. A Cox proportional hazards model was fitted to adjust for confounders.ResultsThe best cut-off values for LMR and NLR were 3.20 and 2.18, respectively. The 5-year PFS was 73.6%. After multivariate adjustment, high LMR (>3.20) at diagnosis was associated with superior PFS, with a HR of 0.31 (95% CI 0.13 to 0.71), whereas high NLR at relapse was associated with poorer postprogression survival (HR 1.24, 95% CI 1.04 to 1.49).ConclusionsBaseline LMR and NLR at relapse were shown to be independent prognostic factors in FL. LMR and NLR are cheap and widely available biomarkers that could be used in combination with the Follicular Lymphoma International Prognostic Index by clinicians to better predict prognosis.