A Machine Learning Approach to Concussion Risk Estimation Among Players Exhibiting Visible Signs in Professional Hockey.

BACKGROUND: The identification of concussion risk factors, such as visible signs and mechanisms of injury, improves concussion identification. Exploring individual risk factors, such as concussion history, may help to improve existing concussion risk models and algorithms. OBJECTIVES: The primary aim of the current study was to use machine learning techniques to develop a comprehensive, prospectively coded concussion risk model in professional hockey among players exhibiting visible signs. The secondary aim was to examine whether including concussion history improves model performance. METHODS: Data from the National Hockey League (NHL) spotter program, including coded visible signs and mechanisms of injury associated with possible concussive events, were extracted from the 2018-2019 to the 2021-2022 seasons. Each unique spotter event was matched with data extracted from the medical record to determine whether the event was associated with a subsequent physician diagnosed concussion. We compared the ability of three machine learning-based approaches to identify the likelihood of physician diagnosed concussion: conditional inference tree, conditional inference random forest, and logistic regression. RESULTS: A total of 1563 unique events with visible signs were identified by spotters (183 leading to a concussion diagnosis). A randomly selected training sample had 1250 events (146 concussions) and the remaining set-aside test sample had 313 events (37 concussions). The obtained models performed at a high level with large effects in the training [area under the receiver operating characteristic curve (AUC) = 0.79] and set-aside test data (AUC = 0.82). Concussion history was retained in the tree and logistic regression models, with each additional prior concussion associated with a 1.32 times increased odds of concussion diagnosis. CONCLUSIONS: We present simple tree and logistic algorithms for concussion screening and as diagnostic aids. Our results show that player concussion history can explain additional risk above and beyond that explained by visible signs and mechanisms of injury alone.

Concussion Characteristics in the National Hockey League Before and After the Introduction of Rule 48.

Importance: A rule prohibiting a direct hit to the lateral side of the head (ie, Rule 48-Illegal Check to the Head) was introduced in the National Hockey League (NHL) in the 2010-2011 season and refined in the 2011-2012 season to widen the application to include direct contact to all areas of the head. Objective: To compare the incidence and proportion of concussions that occurred following hits to the head before and after the implementation of Rule 48. Design, Setting, and Participants: This retrospective cohort study used a before and after design to evaluate concussions among NHL players in regular season games. Data from the 4 seasons preceding the implementation of Rule 48 (2006-2007 to 2009-2010) were compared with data from 5 seasons following its implementation (2014-2015 to 2018-2019). Data were analyzed from October 31, 2021, to November 30, 2022. Main Outcomes and Measures: The incidence and relative proportion of concussion characteristics and mechanisms before and after the introduction of Rule 48. Results: In the analysis of 688 concussions for NHL seasons spanning 2006 to 2010 (n = 231) and 2014 to 2019 (n = 457), there was an overall increase in the incidence of concussion between the 2 time frames, although the incidence of concussions due to hits to the lateral aspect of the head decreased from 1.6/100 games to 1.0/100 games (estimated difference, 0.6/100 games [90% credible interval (CrI), 0.30/100 games to 0.90/100 games). There was also a reduction of 18.8 (90% CrI, 13.0-23.7) percentage points in the proportion of concussions due to hits to the lateral aspect of the head from 80 of 231 concussions (34.6%) to 61 of 457 concussions (13.3%). The incidence of concussions following hits to the head from body checks using the shoulder, arm, and glove was similar before and following the implementation of Rule 48. However, the proportion was reduced 14.7 percentage points from 113 of 231 concussions (48.9%) before to 149 of 457 concussions (32.6%) after implementation of Rule 48 (90% CrI of the difference, 8.9-20.7 percentage points). Conclusions and Relevance: The findings of this cohort study of NHL players suggest that after the introduction of Rule 48, the incidence rate and proportion of concussions from contact to the lateral aspect of the head decreased, as did the proportion of concussions following direct hits to the head.

Prevalence of midline cervical spine tenderness in the non-trauma population.

OBJECTIVE: The Canadian C-Spine Rule (CCR) and the National Emergency X-Radiography Utilization Study (NEXUS) criteria are two commonly used clinical decision rules which use midline cervical spine (c-spine) tenderness on palpation as an indication for c-spine imaging post-trauma. This study was undertaken to determine the prevalence and location of midline c-spine tenderness in the non-trauma population. METHODS: We prospectively evaluated consenting adult patients presenting to an urban ED or university sport medicine clinic in Montreal, Canada between 2018 and 2020 for atraumatic non-head and neck-related reports over a 20-month period. The presence and location of pain during midline c-spine palpation as assessed by two examiners during separate evaluations was recorded. Patient information such as age, neck length and circumference, gender, body mass index (BMI) and scaphoid tenderness was also collected. RESULTS: Of 478 patients enrolled, 286 (59.8%) had midline c-spine tenderness on palpation with both examiners. The majority of those with tenderness were female (70.6%). When examining all patients, tenderness was present in the upper third of the c-spine in 128 (26.8%) patients, middle third in 270 (56.5%) patients and lower third in 6 (1.3%) patients. Factors associated with having increased odds of midline c-spine tenderness on palpation included a lower BMI and the presence of scaphoid tenderness on palpation. CONCLUSIONS: There is a high prevalence of c-spine tenderness on palpation in patients who have not undergone head or neck trauma. This finding may help explain the low specificity in some of the validation studies examining the CCR and the NEXUS criteria.

Do Mountain Bikers Know When They Have Had a Concussion and, Do They Know to Stop Riding?

OBJECTIVE: To establish the prevalence of concussions in mountain bikers and to determine factors that increase their risk of concussion. Secondary objectives include determination of whether mountain bikers have undiagnosed concussions, continue to ride after experiencing concussion symptoms, and if they knowingly ride with a broken helmet. DESIGN: Retrospective survey. SETTING: Seven-day mountain bike stage race. PARTICIPANTS: Two hundred nineteen mountain bikers. MAIN OUTCOME MEASURES: Number of rider concussions diagnosed, number of riders experiencing concussion symptoms without diagnosed concussions, number of riders who continue to ride after experiencing a concussion symptom, and number of riders who rode with a broken helmet. INDEPENDENT VARIABLES: The independent variables studied included age, gender, nationality, number of times riding in past year, style of riding (cross-country, downhill, or freeride), years mountain biking, years mountain bike racing, whether they are a sponsored cyclist, and whether they also ride a road bike. RESULTS: Fifteen of 219 mountain bikers (6.9%) had a diagnosed concussion after being hit in the head while mountain biking within the past year, with older riders having a decreased risk [odds ratio (OR), 0.91; P = 0.04], and sponsored riders having a 5-fold increased risk compared with nonsponsored riders (OR, 4.20; P = 0.05). Twenty-eight riders (12.8%) experienced a concussion symptom without being diagnosed with a concussion and 67.5% of the riders who experienced a concussion symptom continued to ride afterward. Overall, 29.2% of riders reported riding with a broken helmet. CONCLUSIONS: The yearly prevalence of diagnosed concussions in mountain bikers is 6.9%. More than one-third of mountain bikers do not recognize when they have had a concussion and continue riding after experiencing concussion symptoms or with a broken helmet. These behaviors increase their risk of worsening concussion symptoms and acquiring a second injury.

A New In-Skates Balance Error Scoring System for Ice Hockey Players.

OBJECTIVE: Evaluate a new in-skates balance error scoring system (SBESS) for ice hockey players wearing their equipment. DESIGN: Prospective, randomized, single blinded study. SETTING: Sport Medicine Clinic. PARTICIPANTS: Eighty university hockey players. INTERVENTION: A control group performed the SBESS assessment at rest on 2 separate occasions and an experimental group performed the assessment at rest and after exertion. The SBESS consists of maintaining different stances on ice skates for 20 seconds each, while wearing full equipment (no stick, gloves and helmet) and standing on a hard rubber surface. Three independent reviewers scored the video recorded assessments. MAIN OUTCOMES MEASURES: Primary outcome was the number of balance errors and the secondary outcome was the number of falls. RESULTS: The control group's median SBESS scores were 2 and 3 on the first and second attempts at rest, respectively. The experimental group's median SBESS scores were 2 at rest and 2 after exertion. There was no fatigue effect and no athletes fell while performing the test. Of the 4 stances tested, the tandem stance had the highest variability in error scores between athletes and when repeated by the same athlete. The intraclass correlation coefficient (ICC) for interrater reliability was above 0.82, and the intrarater reliability ICC was above 0.86 for all SBESS scores. There was no concordance between the SBESS and the modified BESS. CONCLUSIONS: The SBESS, omitting the tandem stance, is a safe and reproducible sideline balance assessment of ice hockey players wearing full equipment.

An unusual cause of chest pain: Exercise induced sternal fracture in a young man.

This case report describes a 26-year-old male who presented with anterior chest pain after weightlifting at the gym. Point-of-care ultrasound was used to diagnose a sternal fracture, which was then confirmed on CT scan. This rare mechanism of sports related sternal fracture is discussed, as well as a review of the literature. The use of ultrasound for this application is also explored.

Frailty and adverse outcomes in older adults being discharged from the emergency department: A prospective cohort study.

BACKGROUND: A growing number of frail older adults are treated in the emergency department (ED) and discharged home. There is an unmet need to identify older adults that are predisposed to functional decline and repeat ED visits so as to target them with proactive interventions. METHODS: A prospective cohort study was conducted in patients 75 years or older who were being discharged from the ED. The objective was to test the value of frailty screening tests, namely 5-meter gait speed and handgrip strength, to predict repeat ED visits at 1 and 6 months and functional decline at 1 month using multivariable logistic regression. RESULTS: After excluding 7 patients lost to follow-up, 150 patients were available for analysis. The mean age was 81.1 ± 4.9 years with 51% females, 13% arriving by ambulance, and 67% having at least two comorbid conditions. At ED discharge, 41% of patients were found to have slow gait speed, whereas 23% had weak handgrip strength. After adjustment, only slow gait speed was independently associated with functional decline at 1 month (odds ratio [OR] 1.39 per 0.1 meters/second decrement, 95% confidence interval [CI], 1.12 to 1.72) and repeat ED visits at 6 months (OR 1.20 per 0.1 meters/second decrement, 95% CI, 1.01 to 1.42). CONCLUSIONS: Gait speed can be feasibly measured at the time of ED discharge to identify frail older adults at risk for early functional decline and subsequent return to the ED. Conversely, grip strength was not found to be associated with functional decline or ED visits.

Development, implementation and assessment of a concussion education programme for high school student-athletes.

Although experts have noted that adolescent athletes should be educated about concussions to improve their safety, there is no agreement on the most effective strategy to disseminate concussion education. The purpose of this study was to develop, implement and assess a concussion education programme. More precisely, four interactive oral presentations were delivered to high school student-athletes (N = 35, Mage = 15.94, SD = 0.34) in a large urban centre. Participants completed a questionnaire at three time-points during the season to measure changes in their knowledge (CK) and attitudes (CA) of concussions, and focus group interviews were conducted following the concussion education programme. Questionnaire data revealed participants' post-intervention CK scores were higher than their pre-intervention scores. During the focus groups, the student-athletes said they acquired CK about the role of protective equipment and symptom variability, and in terms of CA, they intended to avoid dangerous in-game collisions in the future. Our study was the first to create and deliver a concussion education intervention across multiple time-points, and to use mixed-methods in its assessment. These findings may be of interest to researchers, practitioners and stakeholders in sport who are invested in making the sport environment safer through concussion education and awareness.

Cocaine Cue-Induced Dopamine Release in Recreational Cocaine Users.

It has been proposed that the acquisition of drug seeking is related to the development of conditioned dopamine responses in the ventral striatum. As drug use continues and becomes habit-like, conditioned responses have been shown to shift to the dorsal striatum. Here, using the PET [11C]raclopride method and highly personalized cocaine cues, we report the first evidence in humans of the dorsal dopamine response prior to the onset of addiction.

Modified Balance Error Scoring System (M-BESS) test scores in athletes wearing protective equipment and cleats.

BACKGROUND: Balance testing is an important part of the initial concussion assessment. There is no research on the differences in Modified Balance Error Scoring System (M-BESS) scores when tested in real world as compared to control conditions. OBJECTIVE: To assess the difference in M-BESS scores in athletes wearing their protective equipment and cleats on different surfaces as compared to control conditions. METHODS: This cross-sectional study examined university North American football and soccer athletes. Three observers independently rated athletes performing the M-BESS test in three different conditions: (1) wearing shorts and T-shirt in bare feet on firm surface (control); (2) wearing athletic equipment with cleats on FieldTurf; and (3) wearing athletic equipment with cleats on firm surface. Mean M-BESS scores were compared between conditions. RESULTS: 60 participants were recruited: 39 from football (all males) and 21 from soccer (11 males and 10 females). Average age was 21.1 years (SD=1.8). Mean M-BESS scores were significantly lower (p<0.001) for cleats on FieldTurf (mean=26.3; SD=2.0) and for cleats on firm surface (mean=26.6; SD=2.1) as compared to the control condition (mean=28.4; SD=1.5). Females had lower scores than males for cleats on FieldTurf condition (24.9 (SD=1.9) vs 27.3 (SD=1.6), p=0.005). Players who had taping or bracing on their ankles/feet had lower scores when tested with cleats on firm surface condition (24.6 (SD=1.7) vs 26.9 (SD=2.0), p=0.002). CONCLUSIONS: Total M-BESS scores for athletes wearing protective equipment and cleats standing on FieldTurf or a firm surface are around two points lower than M-BESS scores performed on the same athletes under control conditions.

Why university athletes choose not to reveal their concussion symptoms during a practice or game.

OBJECTIVE: To determine why athletes decide not to seek medical attention during a game or practice when they believe they have suffered a concussion. DESIGN: A retrospective survey. SETTING: University Sport Medicine Clinic. PARTICIPANTS: A total of 469 male and female university athletes from several varsity team sports were participated in the study. MAIN OUTCOME MEASURES: Athletes were surveyed about the previous 12 months to identify specific reasons why those athletes who believed they had suffered a concussion during a game or practice decided not to seek attention at that time, how often these reasons occurred, and how important these reasons were in the decision process. RESULTS: Ninety-two of the 469 athletes (19.6%) believed they had suffered a concussion within the previous 12 months while playing their respective sport, and 72 of these 92 athletes (78.3%) did not seek medical attention during the game or practice at least once during that time. Sports in which athletes were more likely to not reveal their concussion symptoms were football and ice hockey. The reason "Did not feel the concussion was serious/severe and felt you could still continue to play with little danger to yourself," was listed most commonly (55/92) as a cause for not seeking medical attention for a presumed concussion. CONCLUSIONS: A significant percentage of university athletes who believed they had suffered a concussion chose not to seek medical attention at the time of injury. Improved education of players, parents, and coaches about the dangers of continuing to play with concussion symptoms may help improve reporting. CLINICAL RELEVANCE: Medical staff should be aware that university athletes who believe they have suffered a concussion may choose not to volunteer their symptoms during a game or practice for a variety of personal and athletic reasons.

Cervical Spine Motion during Transfer and Stabilization Techniques.

Abstract Objectives. To compare paramedics' ability to minimize cervical spine motion during patient transfer onto a vacuum mattress with two stabilization techniques (head squeeze vs. trap squeeze) and two transfer methods (log roll with one assistant (LR2) vs. 3 assistants (LR4)). Methods. We used a crossover design to minimize bias. Each lead paramedic performed 10 LR2 transfers and 10 LR4 transfers. For each of the 10 LR2 and 10 LR4 transfers, the lead paramedic stabilized the cervical spine using the head squeeze technique five times and the trap squeeze technique five times. We randomized the order of the stabilization techniques and LR2/LR4 across lead paramedics to avoid a practice or fatigue effect with repeated trials. We measured relative cervical spine motion between the head and trunk using inertial measurement units placed on the forehead and sternum. Results. On average, total motion was 3.9° less with three assistants compared to one assistant (p = 0.0002), and 2.8° less with the trap squeeze compared to the head squeeze (p = 0.002). There was no interaction between the transfer method and stabilization technique. When examining specific motions in the six directions, the trap squeeze generally produced less lateral flexion and rotation motion but allowed more extension. Examining within paramedic differences, some paramedics were clearly more proficient with the trap squeeze technique and others were clearly more proficient with the head squeeze technique. Conclusion. Paramedics performing a log roll with three assistants created less motion compared to a log roll with only one assistant, and using the trap squeeze stabilization technique resulted in less motion than the head squeeze technique but the clinical relevance of the magnitude remains unclear. However, large individual differences suggest future paramedic training should incorporate both best evidence practice as well as recognition that there may be individual differences between paramedics.

Should family members witness cardiopulmonary resuscitation?

CLINICAL QUESTION: What is the effect of family presence during cardiopulmonary resuscitation on family members and the medical team? ARTICLE CHOSEN: Jabre P, Belpomme V, Azoulay E, et al. Family presence during cardiopulmonary resuscitation. N Engl J Med 2013;368:1008-18. OBJECTIVE: The authors sought to determine whether systematically offering relatives the option to be present during cardiopulmonary resuscitation increases the proportion of relatives with posttraumatic stress disorder-related symptoms after 90 days. Secondary outcomes included the presence of anxiety and depression symptoms in relatives, the effect of family presence on medical efforts at resuscitation, the well-being of the medical team, and the occurrence of medicolegal claims.

Rate, triggers, severity and management of anaphylaxis in adults treated in a Canadian emergency department.

BACKGROUND: The Cross-Canada Anaphylaxis Registry (C-CARE) assesses the triggers and management of anaphylaxis and identifies predictors of the development of severe allergic reactions and of epinephrine use. Here, we present data from an urban adult tertiary care emergency department (ED) in Montreal, Canada. METHODS: Potential anaphylaxis cases were identified using ICD-10 codes related to anaphylaxis or allergic reactions. Putative cases underwent chart review to ensure they met anaphylaxis diagnostic criteria. Demographic, clinical and management data were collected. Multivariate logistic regressions were conducted to assess the effect of demographic characteristics, triggers, and comorbidities on severity and management of reactions. RESULTS: Among 37,730 ED visits, 0.26% (95% CI 0.21, 0.32) fulfilled the definition of anaphylaxis. Food was the suspected trigger in almost 60% of cases. Epinephrine was not administered in almost half of moderate-to-severe cases, and similar numbers of individuals with moderate-to-severe reactions were not prescribed an epinephrine autoinjector. Reaction to shellfish was associated with more severe reactions (OR 13.9; 95% CI 2.2, 89.4). Older individuals and those not receiving steroids were more likely managed without epinephrine (OR 1.04; 95% CI 1.01, 1.07 and OR 2.97; 95% CI 1.05, 8.39, respectively). CONCLUSIONS: Anaphylaxis accounted for a substantial number of ED visits in adults, and the most common trigger was food. There is non-adherence to guidelines recommending epinephrine use for all cases of anaphylaxis. We postulate that this may be related to concerns regarding the side effects of epinephrine in adults.

Mechanisms of injury for concussions in university football, ice hockey, and soccer.

OBJECTIVE: To examine the mechanisms of injury for concussions in university football, ice hockey, and soccer. DESIGN: Prospective cohort design. SETTING: McGill University Sport Medicine Clinic. PARTICIPANTS: Male and female athletes participating in varsity football, ice hockey, and soccer. MAIN OUTCOME MEASURES: Athletes were followed prospectively over a 10-year period to determine the mechanisms of injury for concussions and whether contact with certain areas of the body or individual variables predisposed to longer recovery from concussions. For soccer, data were collected on whether concussions occurred while attempting to head the ball. RESULTS: There were 226 concussions in 170 athletes over the study period. The side/temporal area of the head or helmet was the most common area to be struck resulting in concussion in all 3 sports. Contact from another player's head or helmet was the most probable mechanism in football and soccer. In hockey, concussion impacts were more likely to occur from contact with another body part or object rather than another head/helmet. Differences in mechanisms of injuries were found between males and females in soccer and ice hockey. Athletes with multiple concussions took longer to return to play with each subsequent concussion. Half of the concussions in soccer were related to attempting to head the soccer ball. CONCLUSIONS: The side of the head or helmet was the most common area to be struck resulting in concussion in all 3 sports. In ice hockey and soccer, there are differences in the mechanisms of injury for males and females within the same sport.

The effect of laryngoscope handle size on possible endotracheal intubation success in university football, ice hockey, and soccer players.

OBJECTIVE: To assess the effectiveness of a standard long-handle laryngoscope and a short-handle laryngoscope on ease of possible intubation in football, ice hockey, and soccer players. DESIGN: Prospective crossover study. SETTING: University Sport Medicine Clinic. PARTICIPANTS: Sixty-two university varsity football (62 males), 45 ice hockey (26 males and 19 females), and 39 soccer players (20 males, 19 females). INTERVENTIONS: Athletes were assessed for different airway and physical characteristics. Three different physicians then assessed the use of laryngoscopes of different handle sizes in supine athletes who were wearing protective equipment while in-line cervical spine immobilization was maintained. MAIN OUTCOME MEASURES: The ease of passage of a laryngoscope blade into the posterior oropharynx of a supine athlete was assessed using both a standard long-handle and a short-handle laryngoscope. RESULTS: Use of a short-handle laryngoscope was easier for all physicians in all sports as compared with a standard-sized laryngoscope. Passage of a laryngoscope blade into the posterior oropharynx of a supine athlete was easiest in soccer players and most difficult in football and ice hockey players for both sizes of laryngoscope. Interference from chest or shoulder pads was a common cause for difficulty in passing the laryngoscope blade into the posterior oropharynx for football and ice hockey players. CONCLUSIONS: In the rare instances that an endotracheal intubation is to be attempted on an unconscious athlete, a short-handle laryngoscope may provide the best chance for successful intubation.

Residents-as-teachers: a survey of Canadian specialty programs.

INTRODUCTION: The ability to teach is a critical component of residency and future practice. This is recognized by the Royal College of Physicians and Surgeons of Canada, which incorporates teaching functions into the CanMEDS competencies. The aim of our study was to identify how emergency medicine specialty programs across Canada prepare their residents for roles as teachers and to compare these results to those of other Royal College specialty programs. METHODS: A 40-item English questionnaire was developed and translated into French. It was e-mailed to the program directors of all Royal College Emergency Medicine (EM), Anesthesia, Diagnostic Radiology, General Surgery, Internal Medicine, Obstetrics and Gynecology, Pediatrics, and Psychiatry residency programs. The survey asked what modalities were in use to teach residents how to teach and allowed respondents to comment on recent changes. RESULTS: Twelve of 13 (92%) EM programs and 78 of 113 (69%) other specialty programs responded. All responding programs incorporated some kind of mandatory teaching responsibilities. Four of 12 (33%) EM programs reserved formal teaching functions for postgraduate year 3 and above, whereas only 7 of 78 (9%) other specialty programs did so. The remaining 71 of 78 (91%) non-EM specialty programs incorporated formal teaching functions in all years of residency. Six of 12 (50%) EM programs offered rotations in clinical medical education compared to only 11 of 78 (14%) other specialty programs. CONCLUSIONS: Canadian EM programs appear to differ from other specialty programs in the way that they develop residents-as-teachers. Half of EM programs offer rotations in clinical medical education, and many introduce formal teaching functions later in residency.

Effects of lowered serotonin transmission on cocaine-induced striatal dopamine response: PET [¹¹C]raclopride study in humans.

BACKGROUND: Low serotonin transmission is thought to increase susceptibility to a wide range of substance use disorders and impulsive traits. AIMS: To investigate the effects of lowered serotonin on cocaine-induced (1.0 mg/kg cocaine, self-administered intranasally) dopamine responses and drug craving. METHOD: In non-dependent cocaine users, serotonin transmission was reduced using the acute tryptophan depletion method. Striatal dopamine responses were measured using positron emission tomography with [(11)C]raclopride. RESULTS: Acute tryptophan depletion increased drug craving and striatal dopamine responses to cocaine. These acute tryptophan depletion-induced increases did not occur in the absence of cocaine. CONCLUSIONS: The results suggest that low serotonin transmission can increase dopaminergic and appetitive responses to cocaine. These findings might identify a mechanism by which individuals with low serotonin are at elevated risk for both substance use disorders and comorbid conditions.