Measurement Properties of the Activities-Specific Balance Confidence Scale in Adults From the General Population With Concussion: A Report From the Toronto Concussion Study.

OBJECTIVE: The aim of this study was to establish the internal consistency and construct validity of the Activities-specific Balance Confidence (ABC) Scale and ABC-6 in adults from the general population with concussion. DESIGN: Prospective analysis. SETTING: Outpatient concussion care clinic. PARTICIPANTS: Adults from the general population with concussion referred to a concussion care clinic within 7 days of injury (N=511). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Balance confidence was assessed with the Activities-specific Balance Confidence (ABC) Scale and the ABC-6. Concussion symptoms were characterized using the Sport Concussion Assessment Tool version 5 (SCAT5) symptom checklist. Instrumented measures of balance and gait included center of pressure velocity and double support time, respectively. Balance was also assessed using the mBESS. RESULTS: The ABC and ABC-6 were strongly correlated (ρ=0.980, P<.001). Cronbach α for ABC and ABC-6 was 0.966 and 0.940, respectively. Factor analysis verified the existence of 2 components of the ABC, 1 including all items of the ABC-6 as well as 3 additional items. ABC and ABC-6 were moderately significantly correlated with SCAT5 symptom number, severity, and symptom domain (ρ=-0.350 to -0.604). However, correlations between ABC and ABC-6 with instrumented measures of balance and gait were not statistically significant, except for double support time during dual-task gait with ABC-6 (ρ=-0.218). CONCLUSIONS: In community-dwelling adults with concussion, the ABC and ABC-6 have good internal consistency. Convergent validity is stronger for symptom endorsement measures within SCAT5 domains, which has a similar construct (subjectivity) to balance confidence. Both the ABC and ABC-6 are valid measures of balance self-efficacy in adults from the general population with concussion. The ABC-6 may be a useful tool for characterizing the effect of concussion on perceptions of the ability to perform functional tasks that challenge balance and mobility.

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.

The Toronto Concussion Study: a prospective investigation of characteristics in a cohort of adults from the general population seeking care following acute concussion, 2016-2020.

Purpose: There is limited research regarding the characteristics of those from the general population who seek care following acute concussion. Methods: To address this gap, a large cohort of 473 adults diagnosed with an acute concussion (female participants = 287; male participants = 186) was followed using objective measures prospectively over 16 weeks beginning at a mean of 5.1 days post-injury. Results: Falls were the most common mechanism of injury (MOI) (n = 137, 29.0%), followed by sports-related recreation (n = 119, 25.2%). Male participants were more likely to be injured playing recreational sports or in a violence-related incident; female participants were more likely to be injured by falling. Post-traumatic amnesia (PTA) was reported by 80 participants (16.9 %), and loss of consciousness (LOC) was reported by 110 (23.3%). In total, 54 participants (11.4%) reported both PTA and LOC. Male participants had significantly higher rates of PTA and LOC after their injury compared to their female counterparts. Higher initial symptom burden was associated with a longer duration of recovery for both male and female participants. Female participants had more symptoms and higher severity of symptoms at presentation compared to male participants. Female participants were identified to have a longer recovery duration, with a mean survival time of 6.50 weeks compared to 5.45 weeks in male participants (p < 0.0001). A relatively high proportion of female and male participants in this study reported premorbid diagnoses of depression and anxiety compared to general population characteristics. Conclusion: Although premorbid diagnoses of depression and/or anxiety were associated with higher symptom burden at the initial visit, the duration of symptoms was not directly associated with a pre-injury history of psychological/psychiatric disturbance. This cohort of adults, from the general population, seeking care for their acute concussion attained clinical and functional recovery over a period of 4-12 weeks.

Optimizing early education provided at the Hull-Ellis Concussion and Research Clinic: A multiple methods evaluation from the Toronto Concussion Study.

OBJECTIVES: The purpose of this study was to determine factors and characteristics associated with changes in knowledge among adults receiving education within the first 8 weeks post-concussion. The study also aimed to understand desired preferences (i.e. content, format) for education post-concussion from the perspective of patients and physicians. METHODS: Patient-participants (17-85 years) were prospectively recruited within one week of a concussion. Participants received education over visits from Weeks 1 to 8 post-injury. Primary outcome measures were participant responses on a concussion knowledge questionnaire at Weeks 1 (n = 334) and 8 (n = 195), and feedback regarding education through interviews. Other variables collected included preexisting medical history, physician assessed recovery and symptoms. RESULTS: There was a significant increase in average knowledge on the concussion knowledge questionnaire across time (71% vs 75% correct; p = 0.004). Participants with higher levels of education, female sex and preexisting diagnoses of depression or anxiety had more correct responses at Week 1. Healthcare providers had varying comfort levels addressing mood-related symptoms. CONCLUSIONS: There is a need to tailor education provided to concussion patients based on preinjury characteristics, i.e., mood disorders and demographic factors. Healthcare providers may need additional training in addressing mood symptoms and should modify the approach to fit patients' unique needs.

Characterizing Symptoms Before and Following Concussion in Professional Hockey.

OBJECTIVE: Examine SCAT5 baseline and acute symptom subscales in professional hockey players. DESIGN: Longitudinal case-control. SETTING: Preseason medical evaluations and suspected concussion evaluations. PARTICIPANTS: NHL/AHL players were given the NHL-modified SCAT5 before the 2018-2019 season (n = 1924). During the season, English-speaking players evaluated within 1 day of injury and diagnosed with concussion (n = 140) were compared with players evaluated for possible concussion, but not given a concussion diagnosis (n = 174). INDEPENDENT VARIABLES: Concussion diagnosis and demographic characteristics. MAIN OUTCOME MEASURES: Postconcussion Symptoms Scale (PCSS) items were subdivided into affective/emotional, cognitive, somatic/physical, sleep, and headache subscales. RESULTS: Cognitive (13%), somatic/physical (10%), sleep (26%), affective (18%), and headache (6%) symptoms were reported by players at baseline. Concussed players reported more acute symptoms than active controls on each of the subscales (all P's < 0.001). Players who underwent a suspected concussion evaluation were more likely to be diagnosed with concussion if they reported affective/emotional symptoms at baseline (P < 0.001). Postinjury cognitive (P < 0.001), somatic/physical (P < 0.001), and headache (P < 0.001) symptoms best differentiated concussed players and active controls. CONCLUSIONS: Player reports of increased cognitive difficulties, somatic/physical difficulties, and headache were most associated with concussion diagnosis at the acute evaluation. An abbreviated "acute" PCSS that includes only headache, cognitive, and/or physical symptoms may be useful for diagnostic purposes when evaluation time is limited. Approximately 2% of players reported significantly elevated affective/emotional symptoms at baseline and report of affective/emotional symptoms at baseline was associated with an increased likelihood of concussion diagnosis among players referred for a suspected concussion evaluation.

Revisiting the ICHD-3 criteria for headache attributed to mild traumatic injury to the head: Insights from the Toronto Concussion Study Analysis of Acute Headaches Following Concussion.

BACKGROUND: There is limited prospective data on the prevalence, timing of onset, and characteristics of acute headache following concussion/mild traumatic brain injury. METHODS: Adults diagnosed with concussion (arising from injuries not related to work or motor vehicle accidents) were recruited from emergency departments and seen within one week post injury wherein they completed questionnaires assessing demographic variables, pre-injury headache history, post-injury headache history, and the Sport Concussion Assessment Tool (SCAT-3) symptom checklist, the Sleep and Concussion Questionnaire (SCQ) and mood/anxiety on the Brief Symptom Inventory (BSI). RESULTS: A total of 302 participants (59% female) were enrolled (mean age 33.6 years) and almost all (92%) endorsed post-traumatic headache (PTH) with 94% endorsing headache onset within 24 hours of injury. Headache location was not correlated with site of injury. Most participants (84%) experienced daily headache. Headache quality was pressure/squeezing in 69% and throbbing/pulsing type in 22%. Associated symptoms included: photophobia (74%), phonophobia (72%) and nausea (55%). SCAT-3 symptom scores, Brief Symptom Inventory and Sleep and Concussion Questionnaire scores were significantly higher in those endorsing acute PTH. No significant differences were found in week 1 acute PTH by sex, history of migraine, pre-injury headache frequency, anxiety, or depression, nor presence/absence of post-traumatic amnesia and self-reported loss of consciousness. CONCLUSIONS: This study highlights the very high incidence of acute PTH following concussion, the timing of onset and characteristics of acute PTH, the associated psychological and sleep disturbances and notes that the current ICHD-3 criteria for headaches attributed to mild traumatic injury to the head are reasonable, the interval between injury and headache onset should not be extended beyond seven days and could, potentially, be shorted to allow for greater diagnostic precision.

The Toronto Concussion Study: Reference Data for Balance and Gait Measures in Community-Dwelling Adults With Concussion.

OBJECTIVE: Concussion can cause deficits in balance and gait. Much of what is known about how concussion affects balance and gait has been derived from studies involving youth, high school, and university athletes. However, investigation into the effects of concussion on balance and gait in community-dwelling young, middle-age, and older aged adults is limited. This study aimed to present descriptive reference values for common balance and gait measures in community-dwelling adults between the ages of 20 and 69 years with concussion. METHODS: In this observational study, 318 participants were enrolled from a concussion care clinic at a rehabilitation hospital in an urban center and were assessed within 7 days of injury. Balance measures included the Balance Error Scoring System (BESS), modified BESS, and center-of-pressure root mean square during quiet standing. Gait measures included velocity (absolute and height adjusted), cadence, and step length during self-paced gait. Data were binned by decade-long age range. RESULTS: Mean (SD) per-decade scores for the BESS ranged from 14.8 (5.1) to 21.8 (5.6) errors and 4.0 (3.0) to 9.4 (4.6) errors for the modified BESS. Mean values for center-of-pressure root mean square in the anteroposterior direction ranged from 0.42 (0.18) to 0.52 (0.26) with the eyes open, and from 0.49 (0.19) to 0.62 (0.39) with eyes closed. Mean absolute gait velocity ranged from 98.5 (9.1) to 119.3 (21.3) cm/s. The range of step length values was 58.2 (6.8) to 66.3 (7.3) cm and cadence ranged from 102.1 (9.8) to 108.6 (10.8) steps/min across age groups. CONCLUSION: These data provide insight into the impact of concussion on balance and mobility in community-dwelling adults across the lifespan. IMPACT: Community-dwelling adults can experience concussion across the lifespan. Availability of reference values for commonly used balance and gait measures can help to inform clinical strategies and progression of recovery of balance and mobility after injury.

Determining Sport Concussion Assessment Tool fifth Edition (SCAT5) reliable change in male professional hockey players.

OBJECTIVES: The purpose of this paper is to provide reliable change metrics and assess the test-retest psychometrics of the Sport Concussion Assessment Tool fifth Edition (SCAT5) in a multilingual sample of professional ice hockey players. METHODS: The SCAT5 was administered to National Hockey League and American Hockey League male professional ice hockey players as part of the 2018 and 2019 season medical evaluations. We extracted data from an existing clinical database of players who were administered two consecutive baseline evaluations and had no intervening concussions to assess psychometric properties (eg, test-retest reliability) and develop reliable change metrics. RESULTS: Overall, 1007 players met inclusion criteria. Players were reassessed on average 344.52 (±62.52) days following their first baseline. Test-retest reliability ranged from r=0.3 to r=0.5. Reliable change metrics for Immediate Memory varied considerably dependent on form order. Significant differences were found between English versus non-English language preference on Immediate Memory and Concentration but not Delayed Memory or the modified Balance Error Scoring System (mBESS). Reliable change indices at the 90% CI were: Symptom Severity (5), Total Symptoms (3), Immediate Memory (3-8), Concentration (2), mBESS (5) and Delayed Memory (2-4). CONCLUSIONS: Our findings highlight the importance of considering form differences and language preference when determining reliable change from baseline on the SCAT5 in male professional hockey players. The relatively modest test-retest reliability of the measures leaves room for improved psychometric properties and increased sensitivity to concussion in future iterations of the SCAT.

The Toronto Concussion Study: Sense of smell is not associated with concussion severity or recovery.

OBJECTIVE: To examine sense of smell as a biomarker for both severity and duration of post-concussion symptoms. METHODS: Participants were recruited prospectively from an outpatient concussion clinic. Sense of smell was assessed using the University of Pennsylvania Smell Identification Test (UPSIT) within 7 days, and 4, 8 - or 16-weeks post-injury. UPSIT normative data were used as normal controls. The main outcomes were: symptom severity on the Sport Concussion Assessment Tool 3 (SCAT3) symptom inventory and time to physician-declared recovery. RESULTS: A total of 167 participants (mean age 32.9 [SD, 12.2] years, 59% female [n = 99]) were classified at 1 week post injury as follows: severe hyposmia in 5 (3%), moderate hyposmia in 10 (6%), mild hyposmia in 48 (29%), and normosmia in 104 (62%) individuals. A convenience sample of 81 individuals with concussion were tested at follow-up. Acute impairment of sense of smell following concussion was not associated with symptom severity on the SCAT3 or time to recovery. Sense of smell was stable from baseline to follow-up in this population. CONCLUSION: This study provides evidence that routine testing of sense of smell in individuals with concussion is not warranted as a biomarker for severity of concussion and concussion recovery.

The Utility of the King-Devick Test in Evaluating Professional Ice Hockey Players With Suspected Concussion.

OBJECTIVE: The purpose of this study was to (1) examine the diagnostic utility of the King-Devick (KD) in professional ice hockey players and (2) determine whether the KD provides unique variance in predicting a diagnosis of concussion when given in combination with the SCAT-5. STUDY DESIGN: Cohort Study. SETTING: Primary care. PATIENTS/PARTICIPANTS: Professional ice hockey players. INDEPENDENT VARIABLES: Diagnosis versus no diagnosis of concussion. MAIN OUTCOME MEASURES: King-Devick and SCAT-5 component scores. METHODS: In part 1, players suspected of having a concussion were evaluated at baseline and acutely with the KD and either the SCAT-3 or the SCAT-5. Players evaluated and not diagnosed with concussion served as active controls. In part 2, a separate group of players suspected of having a concussion was evaluated acutely with both the KD and SCAT-5. RESULTS: In part 1 of this study, 53 concussed players declined in performance on the KD from baseline to acute evaluation, whereas the performance of 76 active controls improved significantly. In part 2 of the study, 75 players were diagnosed with concussion and compared with 80 active controls who were evaluated and not diagnosed with concussion. Concussed players revealed a decline in KD performance from baseline to acute evaluation when compared with controls. However, the KD did not account for significant unique variance in predicting a diagnosis of concussion after accounting for SCAT-5 data. CONCLUSIONS: The KD is useful in differentiating concussed and not concussed athletes acutely, but the KD does not seem to add additional diagnostic value over and above the SCAT-5.

Characterizing Sleep and Wakefulness in the Acute Phase of Concussion in the General Population: A Naturalistic Cohort from the Toronto Concussion Study.

Growing literature links concussion to changes in sleep and wakefulness in humans and in rodent models. Sleep has been linked with synaptic reorganization under other conditions; however, the characterization and role of sleep after acute concussion remains poorly understood. While much research has focused on insomnia among patients with chronic or persistent concussion symptoms, there is limited understanding of sleep and acute concussion, its potential role in recovery, and associated risk factors for the development of chronic sleep disturbance. Studies to date are limited by small sample sizes of primarily athlete or military populations. Additional studies among the general population are critical to inform best practice guidelines. We examined the sleep and daytime wakefulness of 472 adults from a naturalistic general population cohort (mean age, 33.3 years, females = 60.8%) within seven days of diagnosed concussion, using a validated, condition-specific measure, the Sleep and Concussion Questionnaire. Participants identified immediate changes in sleep characterized by hypersomnia and difficulty maintaining daytime wakefulness; 35% considered these changes as moderate to severe and 79% required monitoring or follow-up. Females experienced significantly greater severity of changes in sleep compared with males. Positive correlations between severity of sleep and pain and headache were identified. Differences by sex are an important consideration for early intervention and long-term monitoring. Because sleep was compromised by pain, pain management is also an integral part of early intervention. Our findings suggest that assessment of sleep beginning in the acute stage is a critical component of concussion management in the general population.

A Cross-Sectional Decision-Making Approach to Inform Neuropsychological Battery Development in Professional Hockey.

OBJECTIVE: Neuropsychologists commonly use a large battery of tests to inform clinical decisions. Decision analysis can be used to determine which individual tests play a role in the decision-making process. The objective of this project was to conduct quantitative and qualitative decision analysis of decisions by team neuropsychologists with professional hockey players being evaluated as part of the National Hockey League (NHL)/NHL Players Association Concussion Protocol. METHOD: We extracted neuropsychological data from an NHL clinical program database. Team neuropsychologists evaluated concussed players using a hybrid neuropsychological test battery. The neuropsychologists then determined whether players were experiencing concussion-related cognitive difficulties. Logistic regression was used to examine which tests accounted for unique variance in the decision-making process. We also conducted a survey of NHL neuropsychologists, asking them to rate the usefulness of each test in the battery. RESULTS: Five of the fifteen measures accounted for unique variance in team neuropsychologists' decisions, including the ImPACT Verbal Memory Composite, Visual Motor Composite, Reaction Time Composite, Symptom Score, and Brief Visuospatial Memory Test-Revised Delayed Recall. Notable discrepancies were uncovered between quantitative indications of usefulness and self-reported qualitative perceptions of test usefulness when making decisions. Qualitatively, clinicians reported that the Hopkins Verbal Learning Test-Revised, Symbol Digit Modalities Test, ImPACT Reaction Time, and Color Trails 2 were the most useful tests when making decisions. CONCLUSIONS: Along with validation studies, decision analysis can be used as part of a comprehensive evaluation process to inform the development of best-practice batteries for use among athletes with sports concussion.

Can Sport Concussion Assessment Tool (SCAT) Symptom Scores Be Converted to Rivermead Post-concussion Symptoms Questionnaire (RPQ) Scores and Vice Versa? Findings From the Toronto Concussion Study.

Background: The Rivermead Post-Concussion Symptoms Questionnaire (RPQ) and the Sports Concussion Assessment Tool (SCAT) are widely used self-report tools assessing the type, number, and severity of concussion symptoms. There are overlapping symptoms and domains, though they are scored differently. The SCAT consists of 22 questions with a 7-point Likert scale for a total possible score 132. The RPQ has 16 questions and a 5-point Likert scale for a total of 64 possible points. Being able to convert between the two scores would facilitate comparison of results in the concussion literature. Objectives: To develop equations to convert scores on the SCAT to the RPQ and vice versa. Methods: Adults (17-85 years) diagnosed with a concussion at a referring emergency department were seen in the Hull-Ellis Concussion and Research Clinic, a rapid access concussion clinic at Toronto Rehab-University Health Network (UHN) Toronto Canada, within 7 days of injury. The RPQ and SCAT symptom checklists as well as demographic questionnaires were administered to all participants at Weeks 1, 2, 3, 4, 5, 6, 7, 8, 12, 16. Results: 215 participants had 1,168 matched RPQ and SCAT assessments. Total scores of the RPQ and the SCAT had a rho = 0.91 (p < 0.001); correlations were lower for sub-scores of specific symptom domains (range 0.74-0.87, p < 0.001 for all domain comparisons). An equation was derived to calculate SCAT scores using the number and severity of symptoms on the RPQ. Estimated scores were within 3 points of the observed total score on the SCAT. A second equation was derived to calculate the RPQ from the proportion weighted total score of the SCAT. This equation estimated corresponding scores within 3 points of the observed score on the RPQ. Conclusions: The RPQ and SCAT symptom checklists total scores are highly correlated and can be used to estimate the total score on the corresponding assessment. The symptom subdomains are also strongly correlated between the 2 scales however not as strongly correlated as the total score. The equations will enable researchers and clinicians to quickly convert between the scales and to directly compare concussion research findings.

Prediction of risk of prolonged post-concussion symptoms: Derivation and validation of the TRICORDRR (Toronto Rehabilitation Institute Concussion Outcome Determination and Rehab Recommendations) score.

BACKGROUND: Approximately 10% to 20% of people with concussion experience prolonged post-concussion symptoms (PPCS). There is limited information identifying risk factors for PPCS in adult populations. This study aimed to derive a risk score for PPCS by determining which demographic factors, premorbid health conditions, and healthcare utilization patterns are associated with need for prolonged concussion care among a large cohort of adults with concussion. METHODS AND FINDINGS: Data from a cohort study (Ontario Concussion Cohort study, 2008 to 2016; n = 1,330,336) including all adults with a concussion diagnosis by either primary care physician (ICD-9 code 850) or in emergency department (ICD-10 code S06) and 2 years of healthcare tracking postinjury (2008 to 2014, n = 587,057) were used in a retrospective analysis. Approximately 42.4% of the cohort was female, and adults between 18 and 30 years was the largest age group (31.0%). PPCS was defined as 2 or more specialist visits for concussion-related symptoms more than 6 months after injury index date. Approximately 13% (73,122) of the cohort had PPCS. Total cohort was divided into Derivation (2009 to 2013, n = 417,335) and Validation cohorts (2009 and 2014, n = 169,722) based upon injury index year. Variables selected a priori such as psychiatric disorders, migraines, sleep disorders, demographic factors, and pre-injury healthcare patterns were entered into multivariable logistic regression and CART modeling in the Derivation Cohort to calculate PPCS estimates and forward selection logistic regression model in the Validation Cohort. Variables with the highest probability of PPCS derived in the Derivation Cohort were: Age >61 years ([Formula: see text] = 0.54), bipolar disorder ([Formula: see text] = 0.52), high pre-injury primary care visits per year ([Formula: see text] = 0.46), personality disorders ([Formula: see text] = 0.45), and anxiety and depression ([Formula: see text] = 0.33). The area under the curve (AUC) was 0.79 for the derivation model, 0.79 for bootstrap internal validation of the Derivation Cohort, and 0.64 for the Validation model. A limitation of this study was ability to track healthcare usage only to healthcare providers that submit to Ontario Health Insurance Plan (OHIP); thus, some patients seeking treatment for prolonged symptoms may not be captured in this analysis. CONCLUSIONS: In this study, we observed that premorbid psychiatric conditions, pre-injury health system usage, and older age were associated with increased risk of a prolonged recovery from concussion. This risk score allows clinicians to calculate an individual's risk of requiring treatment more than 6 months post-concussion.

The Toronto concussion study: a cross-sectional analysis of balance deficits following acute concussion in community-dwelling adults.

Objective: To characterize balance deficits in community-dwelling adults following acute concussion.Design: Cross-sectional observational study.Methods: Individuals with acute concussion (n=100) and healthy controls (n=20) completed the BESS (Balance Error Scoring System) and quiet standing trials on forceplates with the eyes open, closed, or during a cognitive dual task. BESS score and centre-of-pressure root mean square and high-frequency power (0.4-3Hz) were used to characterize group differences. In a secondary analysis, participants were subdivided based on self-reported symptoms of balance problems and dizziness using the SCAT-3 (Sport Concussion Assessment Tool - Third Edition) Symptom Checklist.Results: In comparing individuals with concussion and controls, BESS score (16.0 ± 6.0 vs 12.6 ± 3.8; F(1,116) = 5.814, p = .017) and anteroposterior [F(1.78, 204.2) = 11.93, p < .001] and mediolateral [F(1, 114) = 10.05, p = .002] high-frequency power revealed significant group differences. Dividing individuals based on self-reported symptoms revealed significant differences in mediolateral high frequency power, such that participants reporting balance and dizziness problems as well as those participants not reporting balance or dizziness symptoms following concussion were less stable than controls.Conclusions: Deficits in clinical and posturographic measures of balance occur in community-dwelling adults with concussion. These measures do not align with self-reported balance symptoms. Future research and clinical practice aimed at careful selection of optimized balance assessment is recommended.

Normative Data for the Fear Avoidance Behavior After Traumatic Brain Injury Questionnaire in a Clinical Sample of Adults With Mild TBI.

OBJECTIVE: Fear avoidance behavior after a concussion or mild traumatic brain injury (mTBI) is associated with a number of adverse outcomes, such as higher symptom burden, emotional distress, and disability. The Fear Avoidance Behavior after Traumatic Brain Injury Questionnaire (FAB-TBI) is a recently developed and validated self-report measure of fear avoidance after mTBI. The objective of this study was to derive clinical normative data for the FAB-TBI. To determine whether demographic stratification was necessary and to further support clinical interpretation, we also explored associations between fear avoidance behavior and demographic and injury variables. SETTING: Five concussion clinics in Canada. PARTICIPANTS: Adults who sustained an mTBI (N = 563). DESIGN: Cross-sectional. MAIN MEASURES: Participants completed the Fear Avoidance Behavior after Traumatic Brain Injury Questionnaire (FAB-TBI) and measures of postconcussion symptom burden (Rivermead Postconcussion Symptoms Questionnaire, Sport Concussion Assessment Tool-5) at clinic intake. RESULTS: Generalized linear modeling revealed that females reported more fear avoidance than males (95% CI = 0.66 to 2.75), indicating that FAB-TBI normative data should be stratified by sex. Differences between recruitment sites on FAB-TBI scores were reduced but not eliminated by controlling for potential confounds. Loss of consciousness (95% CI =0.61 to 2.76) and higher postconcussion symptom burden (95% CI = 0.79 to 1.03) were also associated with higher FAB-TBI scores, but time since injury was not (95% = CI -0.4 to 0.03). Tables to convert FAB-TBI raw scores to Rasch scores to percentiles are presented. CONCLUSION: These findings support clinical interpretation of the FAB-TBI and further study of fear avoidance after mTBI.

A Promising Subject-Level Classification Model for Acute Concussion Based on Cerebrovascular Reactivity Metrics.

Concussion imaging research has primarily focused on neuronal disruption with lesser emphasis directed toward vascular dysfunction. However, blood flow metrics may be more sensitive than measures of neuronal integrity. Vascular dysfunction can be assessed by measuring cerebrovascular reactivity (CVR)-the change in cerebral blood flow per unit change in vasodilatory stimulus. CVR metrics, including speed and magnitude of flow responses to a standardized well-controlled vasoactive stimulus, are potentially useful for assessing individual subjects following concussion given that blood flow dysregulation is known to occur with traumatic brain injury. We assessed changes in CVR metrics to a standardized vasodilatory stimulus during the acute phase of concussion. Using a case control design, 20 concussed participants and 20 healthy controls (HCs) underwent CVR assessment measuring blood oxygen-level dependent (BOLD) magnetic resonance imaging using precise changes in end-tidal partial pressure of CO2 (PETCO2). Metrics were calculated for the whole brain, gray matter (GM), and white matter (WM) using sex-stratification. A leave-one-out receiver operating characteristic (ROC) analysis classified concussed from HCs based on CVR metrics. CVR magnitude was greater and speed of response faster in concussed participants relative to HCs, with WM showing higher classification accuracy compared with GM. ROC analysis for WM-CVR metrics revealed an area under the curve of 0.94 in males and 0.90 in females for speed and magnitude of response respectively. These greater than normal responses to a vasodilatory stimulus warrant further investigation to compare the predictive ability of CVR metrics against structural injury metrics for diagnosis and prognosis in acute concussion.

Use of the Sport Concussion Assessment Tool 5 (SCAT5) in professional hockey, part 1: cross-cultural normative data.

OBJECTIVES: This paper provides comprehensive normative data stratified by language preference and age on the components of the National Hockey League (NHL) Sport Concussion Assessment Tool 5 (SCAT5) in a multilingual sample of professional ice hockey players and compares the findings from a paper form of the NHL SCAT5 with an electronic (App) version of the tool. METHODS: A total of 1924 male NHL and American Hockey League (AHL) players (ages 17-41) were assessed during preseason medical evaluations (baseline); 1881 were assessed with the NHL SCAT5 App via tablet and 43 received the paper version of the NHL Modified SCAT5. RESULTS: No significant differences between the App and paper modes of administration emerged in a subsample of English preference players. Significant SCAT5 differences among language preference groups emerged on measures of cognitive functioning (Immediate Memory,Concentration). No language preference differences emerged on the Delayed Recall component. Using age as a continuous variable, older participants outperformed younger players on Immediate Memory, Delayed Recall and Concentration. Players wearing skates demonstrated significantly more modified Balance Error Scoring System (mBESS) total errors than barefoot players. Normative data tables for language preference groups are presented. CONCLUSIONS: Significant differences were found between English and non-English language preference groups on the components of SCAT5, which suggest that language-specific normative data, rather than aggregated normative data, are preferable when interpreting test scores. Similarly, age-specific normative data tables may provide greater precision in data interpretation. Due to clear ceiling effects on the mBESS single leg and tandem stances, players should not be tested while wearing skates.

Use of the Sport Concussion Assessment Tool 5 (SCAT5) in professional hockey, part 2: which components differentiate concussed and non-concussed players?

OBJECTIVES: To examine the utility of Sport Concussion Assessment Tool (SCAT5) subcomponents in differentiating physician diagnosed concussed players from controls. METHODS: We evaluated 1924 professional hockey players at training camp using the National Hockey League (NHL) Modified SCAT5 prior to the 2018-2019 season. Over the course of the season, 314 English-speaking players received SCAT5 evaluations within 1 day of a suspected concussive event. Of these players, 140 (45%) were subsequently diagnosed with concussion by their team physicians. RESULTS: Concussed players reported more symptoms (Concussed M=8.52, SD=4.78; Control M=3.32, SD=3.97), and recalled fewer words than Controls on both the Immediate Memory (Concussed M=19.34, SD=4.06; Control M=21.53, SD=2.94) and Delayed Recall (Concussed z=-0.91; Control z=-0.09) tasks during the acute evaluation. Concussed players also made more errors than Controls on the mBESS and were more likely to report double vision and exhibit clinician-observed balance problems than controls. There were no between-group differences on the Concentration component of the SCAT5. Stepwise regression revealed that symptom report and list learning tasks both accounted for independent variance in identifying players diagnosed with concussion. CONCLUSIONS: These findings provide support for use of the SCAT5 to assist in identifying concussed professional hockey players. When examining SCAT5 subtests, both symptom report and the 10-item word list accounted for independent variance in identifying concussion status in this sample of professional hockey players. The mBESS also differentiated Concussed players and Controls. The Concentration component of the SCAT5 did not significantly differentiate Concussed players and Controls.