Brain morphometry in former American football players: findings from the DIAGNOSE CTE research project.

Exposure to repetitive head impacts in contact sports is associated with neurodegenerative disorders including chronic traumatic encephalopathy (CTE), which currently can be diagnosed only at post-mortem. American football players are at higher risk of developing CTE given their exposure to repetitive head impacts. One promising approach for diagnosing CTE in vivo is to explore known neuropathological abnormalities at post-mortem in living individuals using structural MRI. MRI brain morphometry was evaluated in 170 male former American football players ages 45-74 years (n = 114 professional; n = 56 college) and 54 same-age unexposed asymptomatic male controls (n = 54, age range 45-74). Cortical thickness and volume of regions of interest were selected based on established CTE pathology findings and were assessed using FreeSurfer. Group differences and interactions with age and exposure factors were evaluated using a generalized least squares model. A separate logistic regression and independent multinomial model were performed to predict each traumatic encephalopathy syndrome (TES) diagnosis, core clinical features and provisional level of certainty for CTE pathology using brain regions of interest. Former college and professional American football players (combined) showed significant cortical thickness and/or volume reductions compared to unexposed asymptomatic controls in the hippocampus, amygdala, entorhinal cortex, parahippocampal gyrus, insula, temporal pole and superior frontal gyrus. Post hoc analyses identified group-level differences between former professional players and unexposed asymptomatic controls in the hippocampus, amygdala, entorhinal cortex, parahippocampal gyrus, insula and superior frontal gyrus. Former college players showed significant volume reductions in the hippocampus, amygdala and superior frontal gyrus compared to the unexposed asymptomatic controls. We did not observe Age × Group interactions for brain morphometric measures. Interactions between morphometry and exposure measures were limited to a single significant positive association between the age of first exposure to organized tackle football and right insular volume. We found no significant relationship between brain morphometric measures and the TES diagnosis core clinical features and provisional level of certainty for CTE pathology outcomes. These findings suggested that MRI morphometrics detect abnormalities in individuals with a history of repetitive head impact exposure that resemble the anatomic distribution of pathological findings from post-mortem CTE studies. The lack of findings associating MRI measures with exposure metrics (except for one significant relationship) or TES diagnosis and core clinical features suggested that brain morphometry must be complemented by other types of measures to characterize individuals with repetitive head impacts.

ZL006 mitigates anxiety-like behaviors induced by closed head injury through modulation of the neural circuit from the medial prefrontal cortex to amygdala.

Closed head injury is a prevalent form of traumatic brain injury with poorly understood effects on cortical neural circuits. Given the emotional and behavioral impairments linked to closed head injury, it is vital to uncover brain functional deficits and their driving mechanisms. In this study, we employed a robust viral tracing technique to identify the alteration of the neural pathway connecting the medial prefrontal cortex to the basolateral amygdala, and we observed the disruptions in neuronal projections between the medial prefrontal cortex and the basolateral amygdala following closed head injury. Remarkably, our results highlight that ZL006, an inhibitor targeting PSD-95/nNOS interaction, stands out for its ability to selectively reverse these aberrations. Specifically, ZL006 effectively mitigates the disruptions in neuronal projections from the medial prefrontal cortex to basolateral amygdala induced by closed head injury. Furthermore, using chemogenetic approaches, we elucidate that activating the medial prefrontal cortex projections to the basolateral amygdala circuit produces anxiolytic effects, aligning with the therapeutic potential of ZL006. Additionally, ZL006 administration effectively mitigates astrocyte activation, leading to the restoration of medial prefrontal cortex glutamatergic neuron activity. Moreover, in the context of attenuating anxiety-like behaviors through ZL006 treatment, we observe a reduction in closed head injury-induced astrocyte engulfment, which may correlate with the observed decrease in dendritic spine density of medial prefrontal cortex glutamatergic neurons.

Aberrant cortical spine dynamics after concussive injury are reversed by integrated stress response inhibition.

Traumatic brain injury (TBI) is a leading cause of long-term neurological disability in the world and the strongest environmental risk factor for the development of dementia. Even mild TBI (resulting from concussive injuries) is associated with a greater than twofold increase in the risk of dementia onset. Little is known about the cellular mechanisms responsible for the progression of long-lasting cognitive deficits. The integrated stress response (ISR), a phylogenetically conserved pathway involved in the cellular response to stress, is activated after TBI, and inhibition of the ISR-even weeks after injury-can reverse behavioral and cognitive deficits. However, the cellular mechanisms by which ISR inhibition restores cognition are unknown. Here, we used longitudinal two-photon imaging in vivo after concussive injury in mice to study dendritic spine dynamics in the parietal cortex, a brain region involved in working memory. Concussive injury profoundly altered spine dynamics measured up to a month after injury. Strikingly, brief pharmacological treatment with the drug-like small-molecule ISR inhibitor ISRIB entirely reversed structural changes measured in the parietal cortex and the associated working memory deficits. Thus, both neural and cognitive consequences of concussive injury are mediated in part by activation of the ISR and can be corrected by its inhibition. These findings suggest that targeting ISR activation could serve as a promising approach to the clinical treatment of chronic cognitive deficits after TBI.

Sports-related concussion not associated with long-term cognitive or behavioural deficits: the PROTECT-TBI study.

BACKGROUND: The cognitive effects of sports-related concussion (SRC) have been the subject of vigorous debate but there has been little research into long-term outcomes in non-athlete populations. METHODS: This cohort study of UK community-dwelling adults (aged 50-90 years) was conducted between November 2015 and November 2020, with up to 4 years annual follow-up (n=15 214). Lifetime history of concussions was collected at baseline using the Brain Injury Screening Questionnaire. The first analysis grouped participants by type of concussion (no concussion, only SRC, only non-SRC (nSRC), mixed concussions (both SRC and nSRC)) and the second grouped the participants by number (0, 1, 2 or 3+ SRC or nSRC). Mixed models were used to assess the effect of concussion on outcomes including four cognitive domains and one behavioural measure (Mild Behavioural Impairment-C). RESULTS: Analysis of the included participants (24% male, mean age=64) at baseline found that the SRC group had significantly better working memory (B=0.113, 95% CI 0.038, 0.188) and verbal reasoning (B=0.199, 95% CI 0.092, 0.306) compared with those without concussion. Those who had suffered one SRC had significantly better verbal reasoning (B=0.111, 95% CI 0.031, 0.19) and attention (B=0.115, 95% CI 0.028, 0.203) compared with those with no SRC at baseline. Those with 3+ nSRCs had significantly worse processing speed (B=-0.082, 95% CI -0.144 to -0.019) and attention (B=-0.156, 95% CI -0.248 to -0.063). Those with 3+ nSRCs had a significantly worse trajectory of verbal reasoning with increasing age (B=-0.088, 95% CI -0.149 to -0.026). CONCLUSIONS: Compared with those reporting no previous concussions, those with SRC had no cognitive or behavioural deficits and seemed to perform better in some tasks. As indicated by previous studies, sports participation may confer long-term cognitive benefits.

Head trauma results in manyfold increased risk of multiple sclerosis in genetically susceptible individuals.

BACKGROUND: Large register-based studies have reported an association between head trauma and increased risk of multiple sclerosis (MS). We aimed to investigate possible interactions between head trauma and MS-associated HLA genes in relation to MS risk. METHODS: We used a Swedish population-based case-control study (2807 incident cases, 5950 matched controls with HLA genotypes available for 2057 cases, 2887 controls). Subjects with and without a history of self-reported head trauma were compared regarding MS risk, by calculating ORs with 95% CIs using logistic regression models. Additive interaction between head trauma, HLA-DRB1*1501 and absence of HLA-A*0201, was assessed by calculating the attributable proportion (AP) due to interaction. RESULTS: A history of head trauma was associated with a 30% increased risk of subsequently developing MS (OR 1.34, 95% CI 1.17 to 1.53), with a trend showing increased risk of MS with increasing number of head impacts (p=0.03). We observed synergistic effects between recent head trauma and HLA-DRB1*15:01 as well as absence of HLA*02:01 in relation to MS risk (each AP 0.40, 95% CI 0.1 to 0.7). Recent head trauma in individuals with both genetic risk factors rendered an 18-fold increased risk of MS, compared with those with neither the genetic risk factors nor a history of head trauma (OR 17.7, 95% CI 7.13 to 44.1). CONCLUSIONS: Our findings align with previous observations of a dose-dependent association between head trauma and increased risk of MS and add a novel aspect of this association by revealing synergistic effects between recent head trauma and MS-associated HLA genes.

Skull fractures by glass bottles tested on cadaveric heads.

Head trauma is frequently related to the misuse of drinking vessels as weapons. Forensic reports usually evaluate these blunt injuries as having occurred in scenarios where the alcohol intake is high. Fatal consequences are seen in blows with glass bottles aiming at the head. To prove the outcome that a glass bottle thrown to the head could cause, three intact human cadaver heads were impacted with 1-liter glass bottles at 9.5 m/s using a drop-tower. The impact location covered the left temporal bone, sphenoid bone, and zygomatic arch. The contact between the head and the bottle was produced at an angle of 90° with (1) the valve of the bottle, (2) the bottom of the bottle, and (3) with the head rotated 20° in the frontal plane touching again with the bottom of the bottle. The three bottles remained intact after the impact, and the injury outcomes were determined by computed tomography (CT). The alterations were highly dependent on the impact orientation. The outcome varied from no injury to severe bone fractures. In the most injurious case (#3), fractures were identified in the cranial base, sphenoid bone, and zygomatic bone. These testing conditions were selected to replicate one specific legal case, as required by the plaintiff. Physical disputes with bar glassware can lead to complex combinations of blunt and sharp-force injuries. Controlled biomechanical studies can benefit forensic analyses of violence involving glassware by providing a better understanding of the underlying injury mechanisms.

Minor head injury in anticoagulated patients: performance of biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in the detection of intracranial injury. A prospective observational study.

OBJECTIVES: Data in literature indicate that in patients suffering a minor head injury (MHI), biomarkers serum levels could be effective to predict the absence of intracranial injury (ICI) on head CT scan. Use of these biomarkers in case of patients taking oral anticoagulants who experience MHI is very limited. We investigated biomarkers as predictors of ICI in anticoagulated patients managed in an ED. METHODS: We conducted a single-cohort, prospective, observational study in an ED. Our structured clinical pathway included a first head CT scan, 24 h observation and a second CT scan. The outcome was delayed ICI (dICI), defined as ICI on the second CT scan after a first negative CT scan. We assessed the sensitivity (SE), specificity (SP), negative predictive value (NNV) and positive predictive value (PPV) of the biomarkers S100B, NSE, GFAP, UCH-L1 and Alinity TBI in order to identify dICI. RESULTS: Our study population was of 234 patients with a negative first CT scan who underwent a second CT scan. The rate of dICI was 4.7 %. The NPV for the detection of dICI were respectively (IC 95 %): S100B 92.7 % (86.0-96.8 %,); ubiquitin C-terminal hydrolase-L1 (UCH-L1) 91.8 % (83.8-96.6 %); glial fibrillary protein (GFP) 100 % (83.2-100 %); TBI 100 % (66.4-100 %). The AUC for the detection of dICI was 0.407 for S100B, 0.563 for neuron-specific enolase (NSE), 0.510 for UCH-L1 and 0.720 for glial fibrillary acidic protein (GFAP), respectively. CONCLUSIONS: The NPV of the analyzed biomarkers were high and they potentially could limit the number of head CT scan for detecting dICI in anticoagulated patients suffering MHI. GFAP and Alinity TBI seem to be effective to rule out a dCI, but future trials are needed.

Relationship Between Posttraumatic Headache and Depression After Mild Traumatic Brain Injury.

OBJECTIVES: Mild traumatic brain injury (mTBI) can lead to psychiatric and somatic symptoms for some patients, including posttraumatic headache (PTH) and depression. This study attempted to further establish the relationship between PTH and depression following mTBI and investigate whether the presence of PTH immediately following injury can identify patients at risk for developing depressive symptoms up to 6 months later. METHODS: This study was a secondary analysis of data from Head Injury Serum Markers for Assessing Response to Trauma (HeadSMART), a prospective study of adult patients in the emergency department with head injury. Participants included 265 patients who met criteria for mTBI and completed the Rivermead Post-Concussion Symptoms Questionnaire, to identify PTH within 24 hours after injury, and the Patient Health Questionnaire-9, to assess depressive symptoms during follow-up. Measures were completed at the initial visit immediately after the injury in the emergency department and at 1-, 3-, and 6-month follow-up visits. RESULTS: Patients with acute PTH (aPTH) at time of injury were more likely to report PTH at 1, 3, and 6 months. They also had more severe depressive symptoms and a greater likelihood of clinically significant depression at all time points. CONCLUSIONS: Patients with aPTH within 24 hours after injury were more likely to report continued symptoms of PTH and clinically significant depression at 1, 3, and 6 months. These findings provide support for using the presence of aPTH in the emergency department following mTBI as an indicator for monitoring persistent PTH and depressive symptoms in the postacute recovery period.

Risk factors for clinically important traumatic brain injury in minor head injury in older people.

BACKGROUND AND OBJECTIVES: The incidence of traumatic brain injury (TBI) in older individuals is increasing with an increase in the older population. For older people, the required medical interventions and hospitalization following minor head injury have negative impacts, which have not been reported in literature up till now. We aimed to investigate the risk factors for clinically important traumatic brain injury (ciTBI) in older patients with minor head injury. METHODS: This is a retrospective single-center cohort study. Older patients aged ≥65 years presenting with head injury and a Glasgow Coma Scale (GCS) score of ≥13 upon arrival at the hospital between January 1, 2018, and October 31, 2021, were included. Patients with an injury duration of ≥24 h were excluded. The primary outcome was defined as ciTBI (including death, surgery, intubation, medical interventions, and hospital stays of ≥2 nights). Multiple logistic regression analysis was conducted to identify the risk factors. RESULTS: A total of 296 patients were included initially, and 6 of them were excluded subsequently. ciTBI was identified in 62 cases. According to the results of the multiple logistic regression analysis, GCS scores of ≤14 (OR 3.72, 95% CI 1.89-7.30), high-risk mechanisms of injury (OR 2.80, 95% CI 1.39-5.64), vomiting (OR 5.01, 95% CI 1.19-21.1), and retrograde amnesia (OR 6.90, 95% CI 3.37-14.1) were identified as risk factors. CONCLUSION: In older patients with minor head injury, GCS ≤14, high-risk mechanisms of injury, vomiting, and retrograde amnesia are risk factors for ciTBI.

Minor head injury in anticoagulated patients: Outcomes and analysis of clinical predictors. A prospective study.

BACKGROUND: The optimal management of patients taking oral anticoagulants who experience minor head injury (MHI) is unclear. The availability of validated protocols and reliable predictors of prognosis would be of great benefit. We investigated clinical factors as predictors of clinical outcomes and intracranial injury (ICI). METHODS: We conducted a single-cohort, prospective, observational study in an ED. Our structured clinical pathway included a first head CT scan, 24 h observation and a second CT scan. The primary outcome was the occurrence of MHI-related death or re-admission to ED at day +30. The secondary outcome was the rate of delayed ICI (dICI), defined as second positive CT scan after a first negative CT scan. We assessed some clinical predictors derived from guidelines and clinical prediction rules as potential risk factors for the outcomes. RESULTS: 450 patients with a negative first CT scan who underwent a second CT scan composed our 'study population'. The rate of the primary outcome was 4%. The rate of the secondary outcome was 4.7%. Upon univariate and multivariate analysis no statistically significant predictors for the outcomes were found. CONCLUSIONS: Previous retrospective studies showed a lot of negative predictive factors for anticoagulated patients suffering a minor head injury. In our prospective study no clinical factors emerged as predictors of poor clinical outcomes and dICI. So, even if we confirmed a low rate of adverse outcomes, the best management of these patients in ED remains not so clear and future trials are needed.

Repetitive head-injury exposure and later-in-life cognitive and emotional outcomes among former collegiate football players: a CLEAATS investigation.

This study measured the relationship between head-injury exposure and later-in-life cognitive and emotional symptoms in aging collegiate football players who participated in the College Level Aging Athlete Study. Linear regressions examined the relationship between various head-injury exposure variables (head-injury exposure estimate [HIEE], number of diagnosed concussions, and symptomatic hits to the head) and subjective cognitive function, objective cognitive function, and emotional/mood symptoms. Additional regressions evaluated the impact of emotional symptoms on subjective cognitive decline and objective cognitive function. Participants (n = 216) were 50-87 years old (M = 63.4 [8.5]), 91% White, and well-educated (bachelor's/graduate degree = 92%). HIEE did not predict scores on cognitive or emotional/mood symptom measures (p's > .169). Diagnosed concussions had a small effect on depression symptoms (p = .002, b = 0.501, R2 = .052) and subjective cognitive symptoms (p = .002, b = 0.383, R2 = .051). An emotional symptom index had a stronger relationship (p < .001, b = 0.693, R2 = .362) with subjective cognitive functioning but no significant relationship with objective cognitive function (p = .052, b = -0.211, R2 = .020). Controlling for emotional symptoms, the relationship between concussions and subjective cognitive symptoms was attenuated (p = .078, R2 = .011). Findings suggested that head-injury exposure was not significantly related to cognitive or emotional/mood outcomes in former collegiate football players and highlighted the importance of current emotional/mood symptoms on subjective cognitive function.

Incidence of intraoperative hypotension and its factors among adult traumatic head injury patients in comprehensive specialized hospitals, Northwest Ethiopia: a multicenter observational study.

INTRODUCTION: Traumatic head injury (THI) poses a significant global public health burden, often contributing to mortality and disability. Intraoperative hypotension (IH) during emergency neurosurgery for THI can adversely affect perioperative outcomes, and understanding associated risk factors is essential for prevention. METHOD: A multi-center observational study was conducted from February 10 to June 30, 2022. A simple random sampling technique was used to select the study participants. Patient data were analyzed using bivariate and multivariate logistic regression to identify significant factors associated with intraoperative hypotension (IH). Odds ratios with 95% confidence intervals were used to show the strength of association, and P value < 0.05 was considered as statistically significant. RESULT: The incidence of intra-operative hypotension was 46.41% with 95%CI (39.2,53.6). The factors were duration of anesthesia ≥ 135 min with AOR: 4.25, 95% CI (1.004,17.98), severe GCS score with AOR: 7.23, 95% CI (1.098,47.67), intracranial hematoma size ≥ 15 mm with AOR: 7.69, 95% CI (1.18,50.05), and no pupillary abnormality with AOR: 0.061, 95% CI (0.005,0.732). CONCLUSION AND RECOMMENDATION: The incidence of intraoperative hypotension was considerably high. The duration of anesthesia, GCS score, hematoma size, and pupillary abnormalities were associated. The high incidence of IH underscores the need for careful preoperative neurological assessment, utilizing CT findings, vigilance for IH in patients at risk, and proactive management of IH during surgery. Further research should investigate specific mitigation strategies.

Basal cisternostomy as an adjunct to decompressive hemicraniectomy in moderate to severe traumatic brain injury: a systematic review and meta-analysis.

BACKGROUND: Basal cisternostomy (BC) is a surgical technique to reduce intracranial hypertension following moderate to severe traumatic brain injury (TBI). As the efficacy and safety of BC in patients with TBI has not been well-studied, we aim to summarize the published evidence on the effect of BC as an adjunct to decompressive hemicraniectomy (DHC) on clinical outcome following moderate to severe TBI. METHODS: A systematic literature review was carried out in PubMed/MEDLINE and EMBASE to identify studies evaluating BC as an adjunct to decompressive hemicraniectomy (DHC) in moderate to severe TBI. Random effects meta-analysis was performed to calculate summary effect estimates. RESULTS: Eight studies reporting on 1345 patients were included in the qualitative analysis, of which five (1206 patients) were considered for meta-analysis. Overall, study quality was low and clinical heterogeneity was high. Adjuvant BC (BC + DHC) compared to standalone DHC was associated with a reduction in the length of stay in the ICU (Mean difference [MD]: -3.25 days, 95% CI: -5.41 to -1.09 days, p = 0.003), significantly lower mean brain outward herniation (MD: -0.68 cm, 95% CI: -0.90 to -0.46 cm, p < 0.001), reduced odds of requiring osmotherapy (OR: 0.09, 95% CI: 0.02 to 0.41, p = 0.002) as well as decreased odds of mortality at discharge (OR 0.68, 95% CI: 0.4 to 0.96, p = 0.03). Adjuvant BC compared to DHC did not result in higher odds of a favourable neurological outcome (OR = 2.50, 95% CI: 0.95-6.55, p = 0.06) and did not affect mortality at final follow-up (OR: 0.80, 95% CI: 0.17 to 3.74, p = 0.77). CONCLUSION: There is insufficient data to demonstrate a potential beneficial effect of adjuvant BC. Despite some evidence for reduced mortality and length of stay, there is no effect on neurological outcome. However, these results need to be interpreted with caution as they carry a high risk of bias due to overall scarcity of published clinical data, technical variations, methodological differences, limited cohort sizes, and a considerable heterogeneity in study design and reported outcomes.

Effect of Structure and Wearing Modes on the Protective Performance of Industrial Safety Helmet.

This study aims to explore the effects of helmet structure designs and wearing modes on the protective performance of safety helmets under the impact of falling objects. Four helmet types (no helmet, V-shaped, dome-shaped, and motorcycle helmets) and five wearing modes (left and right tilt by 5 deg, backward tilt by 15 deg, 0 deg without chin strap, 0 deg with chin strap) were included in this study. The axial impact of a concrete block under various impact velocities was simulated. The results indicate that the energy absorption and shock mitigation effects of the foam cushion are superior to those of the suspension system in traditional industrial safety helmets. The structure of the top of V-shaped helmets is designed to withstand greater impact. Regarding the wearing mode, the helmet strap's deflection angle increases stress in the brain tissue and skull, heightens intracranial pressure, and causes pressure diffusion toward the forehead.

Pediatric sport and nonsport concussions presenting to emergency departments: injury circumstances, characteristics, and clinical management.

OBJECTIVE: The aim of this study was to compare injury circumstances, characteristics, and clinical management of emergency department (ED) presentations for sports-related concussion (SRC) and non-SRC. METHODS: This multicenter prospective observational study identified patients 5-17 years old who presented to EDs within 24 hours of head injury, with one or more signs or symptoms of concussion. Participants had a Glasgow Coma Scale score of 13-15 and no abnormalities on CT (if performed). Data were stratified by age: young children (5-8 years), older children (9-12 years), and adolescents (13-17 years). RESULTS: Of 4709 patients meeting the concussion criteria, non-SRC accounted for 56.3% of overall concussions, including 80.9% of younger child, 51.1% of older child, and 37.0% of adolescent concussions. The most common mechanism of non-SRC was falls for all ages. The most common activity accounting for SRC was bike riding for younger children, and rugby for older children and adolescents. Concussions occurring in sports areas, home, and educational settings accounted for 26.2%, 21.8%, and 19.0% of overall concussions. Concussions occurring in a sports area increased with age, while occurrences in home and educational settings decreased with age. The presence of amnesia significantly differed for SRC and non-SRC for all age groups, while vomiting and disorientation differed for older children and adolescents. Adolescents with non-SRC were admitted to a ward and underwent CT at higher proportions than those with SRC. CONCLUSIONS: Non-SRC more commonly presented to EDs overall, with SRC more common with increasing age. These data provide important information to inform public health policies, guidelines, and prevention efforts.

Concussions in ice hockey: mixed methods study including assessment of concussions on games missed and cap hit among National Hockey League players, systematic review, and concussion protocol analysis.

OBJECTIVE: Concussions can occur at any level of ice hockey. Incidence estimates of concussions in ice hockey vary, and optimal prevention strategies and return-to-play (RTP) considerations have remained in evolution. The authors performed a mixed-methods study with the aim of elucidating the landscape of concussion in ice hockey and catalyzing initiatives to standardize preventative mechanisms and RTP considerations. METHODS: The authors performed a five-part mixed-methods study that includes: 1) an analysis of the impact of concussions on games missed and income for National Hockey League (NHL) players using a publicly available database, 2) a systematic review of the incidence of concussion in ice hockey, 3) a systematic review of preventative strategies, 4) a systematic review of RTP, and 5) a policy review of documents from major governing bodies related to concussions in sports with a focus on ice hockey. The PubMed, Embase, and Scopus databases were used for the systematic reviews and focused on any level of hockey. RESULTS: In the NHL, 689 players had 1054 concussions from the 2000-2001 to 2022-2023 seasons. A concussion led to a mean of 13.77 ± 19.23 (range 1-82) games missed during the same season. After cap hit per game data became available in 2008-2009, players missed 10,024 games due to 668 concussions (mean 15.13 ± 3.81 per concussion, range 8.81-22.60 per concussion), with a cap hit per game missed of $35,880.85 ± $25,010.48 (range $5792.68-$134,146.30). The total cap hit of all missed games was $385,960,790.00, equating to $577,635.91 per concussion and $25,724,052.70 per NHL season. On systematic review, the incidence of concussions was 0.54-1.18 per 1000 athlete-exposures. Prevention mechanisms involved education, behavioral and cognitive interventions, protective equipment, biomechanical studies, and policy/rule changes. Rules prohibiting body checking in youth players were most effective. Determination of RTP was variable. Concussion protocols from both North American governing bodies and two leagues mandated that a player suspected of having a concussion be removed from play and undergo a six-step RTP strategy. The 6th International Conference on Concussion in Sport recommended the use of mouthguards for children and adolescents and disallowing body checking for all children and most levels of adolescents. CONCLUSIONS: Concussions in ice hockey lead to substantial missed time from play. The authors strongly encourage all hockey leagues to adopt and adhere to age-appropriate rules to limit hits to the head, increase compliance in wearing protective equipment, and utilize high-quality concussion protocols.

The association between head injury and facial fracture treatment: an observational study of hospitalized bicyclists from a level 1 trauma centre.

PURPOSE: To compare the types of facial fractures and their treatment in bicyclists admitted to a level 1 trauma centre with major and minor-moderate head injury. METHODS: Retrospective analysis of data from bicycle-related injuries in the period 2005-2016 extracted from the Oslo University Hospital trauma registry. RESULTS: A total of 967 bicyclists with head injuries classified according to the Abbreviated Injury Scale (AIS) were included. The group suffering minor-moderate head injury (AIS Head 1-2) included 518 bicyclists, while 449 bicyclists had major head injury (AIS Head 3-6). The mean patient age was 40.2 years (range 3-91 years) and 701 patients (72%) were men. A total of 521 facial fractures were registered in 262 patients (on average 2 facial fractures per bicyclist). Bicyclists with major head injury exhibited increased odds for facial fractures compared to bicyclists with minor-moderate head injury (sex and age adjusted odds ratio (OR) 2.75, 95% confidence interval (CI) 2.03-3.72, p < 0.001. More specifically, there was increased odds for all midface fractures, but no difference for mandible fractures. There was also increased odds for orbital reconstruction in cyclist with major head injury compared to bicyclist with minor-moderate head injury (adjusted OR 3.34, 95% CI 1.30-8.60, p = 0.012). CONCLUSION: Bicyclists with more severe head injuries had increased odds for midface fractures and surgical correction of orbital fractures. During trauma triage, the head and the face should be considered as one unit.

Bicycle helmets are associated with fewer and less severe head injuries and fewer neurosurgical procedures.

PURPOSE: This study explores the protective capabilities of bicycle helmets on serious head injury among bicyclists hospitalized in a Norwegian level 1 trauma centre. METHOD: Information on helmet use, demographic variables, Abbreviated Injury Scale (AIS) and surgical procedure codes was retrieved from the Oslo University Hospital Trauma Registry for patients with bicycle-related injuries from 2005 through 2016. Outcomes were serious head injury defined as maximum AIS severity score ≥ 3 in the AIS region Head, any cranial neurosurgical procedure, and 30-day mortality. RESULTS: A total of 1256 hospitalized bicyclists were included. The median age was 41 years (quartiles 26-53), 73% were male, 5.3% had severe pre-injury comorbidities, and 54% wore a helmet at the time of injury. Serious head injury occurred in 30%, 9% underwent a cranial neurosurgical procedure, and 30-day mortality was 2%. Compared to non-helmeted bicyclists, helmeted bicyclists were older (43 years, quartiles 27-54, vs. 38 years, quartiles 23-53, p = 0.05), less often crashed during night-time (21% vs. 38%, p < 0.001), less frequently had serious head injury (22% vs. 38%, OR 0.29, 95% CI 0.22-0.39), and less often underwent cranial neurosurgery (6% vs. 14%, OR 0.36, 95% CI 0.24-0.54). No statistically significant difference in 30-day mortality between the two groups was found (1.5% vs. 2.9%, OR 0.50, 95% CI 0.22-1.11). CONCLUSION: Helmet use was associated with fewer and less severe head injuries and fewer neurosurgical procedures. This adds evidence to the protective capabilities of bicycle helmets.

Incidence of surgically treated chronic subdural hematoma after head injury with normal initial computed tomography.

PURPOSE: The objective was to determine the incidence of surgically treated chronic subdural hematoma (cSDH) within six months after head trauma in a consecutive series of head injury patients with a normal initial computed tomography (CT). METHODS: A total of 1941 adult patients with head injuries who underwent head CT within 48 h after injury and were treated at the Tampere University Hospital's emergency department were retrospectively evaluated from medical records (median age = 59 years, IQR = 39-79 years, males = 58%, patients using antithrombotic medication = 26%). Patients with no signs of acute traumatic intracranial pathology or any type of subdural collection on initial head CT were regarded as CT negative (n = 1573, 81%). RESULTS: Two (n = 2) of the 1573 CT negative patients received surgical treatment for cSDH. Consequently, the incidence of surgically treated cSDH after a normal initial head CT during a six-month follow-up was 0.13%. Both patients sustained mild traumatic brain injuries initially. One of the two patients was on antithrombotic medication (warfarin) at the time of trauma, hence incidence of surgically treated cSDH among patients with antithrombotic medication in CT negative patients (n = 376, 23.9%) was 0.27%. Additionally, within CT negative patients, one subdural hygroma was operated shortly after trauma. CONCLUSION: The extremely low incidence of surgically treated cSDH after a normal initial head CT, even in patients on antithrombotic medication, supports the notion that routine follow-up imaging after an initial normal head CT is not indicated to exclude the development of cSDH. Additionally, our findings support the concept of cSDH not being a purely head trauma-related disease.

Team-based rehabilitation after mild traumatic brain injury - description of the clinical pathway.

PURPOSE: Describe clinical practice, inter-disciplinary clinical pathway and core principles of care within a mild traumatic brain injury (mTBI) rehabilitation team. METHODS: An observational study examined inter-disciplinary practice, nested within an observational trial investigating team-based mTBI rehabilitation. Data were collected to describe clinical service over 12 months. Activity data quantified clinical sessions per participant, mode of service delivery and content of sessions using custom-designed codes. The clinical team gathered narrative data to confirm the inter-disciplinary clinical pathway and individual discipline practice. RESULTS: 168 participants entered the rehabilitation program during the 12 months. A single Allied Health Screening Assessment identified patient priorities. Occupational Therapy (OT) and Physiotherapy (PT) provided the majority of clinical sessions; the team also comprised Social Work, Rehabilitation Medicine, Speech Pathology and Clinical Psychology. Telehealth was the most common service delivery mode (54%). Median session numbers per participant ranged 1-4 for all disciplines; mean/maximum occasions of service were highest for PT (6.9/44) and OT (6.8/39). CONCLUSION: A small proportion of participants received much higher number of sessions, consistent with intractable issues after mTBI. High attendance rates indicate the predominantly telehealth-delivered model was feasible. The clinical approach included early prioritizing of discipline input and follow-up after discharge.