Doug Richards

Emotional response to sport concussion compared to ACL injury

Primary objectives: To ascertain and compare the nature of emotional response of athletes to concussion and to anterior cruciate ligament (ACL) injury. Research design: Pre-injury, post-injury and longitudinal emotional functioning of athletes with concussion (n = 16), athletes with ACL injuries (n = 7) and uninjured athletes (n = 28) were compared in a prospective repeated-measures design. Methods and procedures: Participants completed the short version of the Profile of Mood States (POMS). ANOVAs and trend analysis were used to examine between and within group differences across time on two sub-scales, Total Mood Disturbance and Depression. Main outcomes and results: Athletes with ACL injury reported higher levels of depression for a longer duration than athletes with concussion. Relative to un-injured controls, athletes with concussion reported significant changes in Total Mood Disturbance and Depression post-injury, whereas athletes with ACL injuries reported significant changes in Depression scores only. Different patterns of post-injury emotional disturbance for the injured groups were observed by trend analyses. Conclusions: Concussed athletes do not report as much emotional disturbance as athletes with ACL injuries. Differential patterns of emotional disturbance were detected between injured groups. The authors recommended that clinical protocols and educational programmes address emotional sequelae associated with sport concussion and ACL injury.

Differential emotional responses of varsity athletes to concussion and musculoskeletal injuries.

Objective: To determine if athletes with concussion and those with minor musculoskeletal injuries experienced differential emotional response to injury. Design: A prospective longitudinal cohort study. Setting: University of Toronto, Ontario, Canada. Participants: Thirty-four injured athletes from Canadian Interuniversity Sport (CIS) and 19 healthy, physically active undergraduate students participated in the study. Intervention: All participants completed the Profile of Mood States (POMS; short version) on 3 nonconsecutive days during a 2-week period after a baseline test. Main Outcome Measures: Emotional responses were assessed using the POMS. The 7 main outcome measures assessed by POMS were tension, depression, anger, vigor, fatigue, confusion, and total mood disturbance. Results: After injury, concussion produced an emotional profile characterized by significantly elevated fatigue and decreased vigor. In contrast, athletes with musculoskeletal injuries displayed a significant increase in anger that resolved to a pre-injury level within 2 weeks. Conclusions: The results revealed that both injured groups experienced emotional disturbance after injury. More importantly, the findings strongly suggest that the emotional reaction after concussion is different from that of musculoskeletal injury. Therefore, we concluded that assessing emotional reactions to concussion is particularly important and recommend that sports medicine professionals assess and monitor emotional functioning as well as somatic complaints and neurocognitive changes during recovery.

Does the Apolipoprotein e4 Allele Predispose Varsity Athletes to Concussion? A Prospective Cohort Study

Objective:To determine the association between the apolipoprotein ϵ4 allele and concussion. We hypothesized that apolipoprotein ϵ4 carriers may be more likely to sustain a concussion. Design:Prospective cohort study. Setting:University of Toronto varsity athletics. Participants:Included 318 of 822 collegiate student athletes who participated in University of Toronto varsity sports from September 2002 to April 2006. Assessment of Risk Factors:The presence of apolipoprotein ϵ4 was described dichotomously after genotyping blood samples collected from participants. Main Outcome Measurements:Concussions were identified by sport-medicine professionals present on the sidelines using on-field assessment forms. All concussion diagnoses were verified by a sports medicine physician. Survival analysis was used to determine the association between apolipoprotein ϵ4 and first concussion. Results:The unadjusted hazard ratio for concussion in the apolipoprotein ϵ4 carriers was 1.18 (95% CI: 0.52, 2.69) compared to noncarriers. Adjustment for sex, weight, height, and team type resulted in a hazard ratio of 1.06 (95% CI: 0.41, 2.72), indicating little effect from confounding factors. Conclusions:There is no important association between carrying the apolipoprotein ϵ4 allele and sustaining a concussion. At this time, we do not recommend preseason genetic testing for varsity athletes as a mechanism for targeting prevention strategies.

The Influence of Musculoskeletal Injury on Cognition: Implications for Concussion Research

Background: Safe return-to-play decisions after concussion can be challenging for sports medicine specialists. Neuropsychological testing is recommended to objectively measure concussion-related cognitive impairments. Purpose: The objective of this study was to measure cognitive functioning among 3 specific athletic groups: (1) athletes with no injuries (n = 36), (2) athletes with musculoskeletal injuries (n = 18), and (3) athletes with concussion (n = 18). Study Design: Case-control study; Level of evidence, 3. Methods: Seventy-two intercollegiate athletes completed preseason baseline cognitive testing and follow-up assessment using the Automated Neuropsychological Assessment Metrics (ANAM) test battery. Injured athletes were tested within 72 hours of injury. A 1-way analysis of covariance adjusted for baseline scores was performed to determine if differences existed in cognitive test scores among the 3 groups. Results: A group of athletes with concussion performed significantly worse than a group of athletes with no injuries on the following subtests of the ANAM at follow-up: Code Substitution Learning, Match to Sample, and Simple Reaction. Athletes with musculoskeletal injuries performed significantly worse than those with no injury on the Match to Sample subtest. No significant differences between athletes with concussion and athletes with musculoskeletal injuries were found on all ANAM subtests. Conclusion: Concussion produces cognitive impairment in the acute recovery period. Interestingly, athletes with musculoskeletal injuries also display a degree of cognitive impairment as measured by computerized tests. Clinical Relevance: Although these findings support previous research that neuropsychological tests can effectively measure concussion-related cognitive impairment, this study provides evidence that athletic injury, in general, also may produce a degree of cognitive disruption. Therefore, a narrow interpretation of scores of neuropsychological tests in a sports concussion context should be avoided.

Brain Structure and Function Associated with a History of Sport Concussion: A Multi-Modal Magnetic Resonance Imaging Study.

There is growing concern about the potential long-term consequences of sport concussion for young, currently active athletes. However, there remains limited information about brain abnormalities associated with a history of concussion and how they relate to clinical factors. In this study, advanced MRI was used to comprehensively describe abnormalities in brain structure and function associated with a history of sport concussion. Forty-three athletes (21 male, 22 female) were recruited from interuniversity teams at the beginning of the season, including 21 with a history of concussion and 22 without prior concussion; both groups also contained a balanced sample of contact and noncontact sports. Multi-modal MRI was used to evaluate abnormalities in brain structure and function. Athletes with a history of concussion showed frontal decreases in brain volume and blood flow. However, they also demonstrated increased posterior cortical volume and elevated markers of white matter microstructure. A greater number of prior concussions was associated with more extensive decreases in cerebral blood flow and insular volume, whereas recovery time from most recent concussion was correlated with reduced frontotemporal volume. White matter showed limited correlations with clinical factors, predominantly in the anterior corona radiata. This study provides the first evidence of the long-term effects of concussion on gray matter volume, blood flow, and white matter microstructure within a single athlete cohort. This was examined for a mixture of male and female athletes in both contact and noncontact sports, demonstrating the relevance of these findings for the overall sporting community.

Psychological and Physiological Markers of Stress in Concussed Athletes Across Recovery Milestones.

Background: Sport-related concussions are associated with a range of physical, cognitive, and behavioral disturbances that are highly variable across individuals. Much remains unknown about the effects of sport concussion, and changes in markers of psychological and physiological stress over the recovery timeline. Objective: To examine psychological (mood, stress, sleep quality, and symptoms) and physiological (heart rate variability and salivary cortisol) measures in concussed athletes over clinical recovery milestones. Setting: University athletic program, sport medicine clinic, Canada. Participants: A sample of 52 interuniversity athletes (32 male and 20 female), 26 with concussion and 26 healthy controls. Design: Case-control repeated measures study at 3 time points of the clinical recovery process. Measures were administered to a matched control sample of uninjured athletes as well. Main Measures: Physiological measures were heart rate variability and salivary cortisol; psychological measures were mood, perceived stress, and quality of sleep. Results: Psychological measures were significantly worse for concussed athletes relative to controls at the symptomatic phase (acute injury), but significantly better at return-to-play (RTP). Multivariate analysis of heart rate variability identified main effects of sex and concussion, with reduced high-frequency heart rate variability for females and concussed athletes extending into the post-RTP phase. An interaction effect was also observed, showing the cardiac response of female athletes was more sensitive to concussion compared with males. Conversely, male athletes showed greater suppression of low-frequency heart rate variability associated with mood disturbances. Conclusion: This integrated study of psychological and physiological markers in concussed athletes confirmed the resolution of mood disturbances, symptoms, and sleep quality by RTP, but identified autonomic nervous system disturbances, as measured by depressed heart rate variability beyond RTP.

The first week after concussion: Blood flow, brain function and white matter microstructure

Concussion is a major health concern, associated with short-term deficits in physical function, emotion and cognition, along with negative long-term health outcomes. However, we remain in the early stages of characterizing MRI markers of concussion, particularly during the first week post-injury when symptoms are most severe. In this study, 52 varsity athletes were scanned using Magnetic Resonance Imaging (MRI), including 26 athletes with acute concussion (scanned 1–7 days post-injury) and 26 matched control athletes. A comprehensive set of functional and structural MRI measures were analyzed, including cerebral blood flow (CBF) and global functional connectivity (Gconn) of grey matter, along with fractional anisotropy (FA) and mean diffusivity (MD) of white matter. An analysis comparing acutely concussed athletes and controls showed limited evidence for reliable mean effects of acute concussion, with only MD showing spatially extensive differences between groups. We subsequently demonstrated that the number of days post-injury explained a significant proportion of inter-subject variability in MRI markers of acutely concussed athletes. Athletes scanned at early acute injury (1–3 days) had elevated CBF and Gconn and reduced FA, but those scanned at late acute injury (5–7 days) had the opposite response. In contrast, MD showed a more complex, spatially-dependent relationship with days post-injury. These novel findings highlight the variability of MRI markers during the acute phase of concussion and the critical importance of considering the acute injury time interval, which has significant implications for studies relating acute MRI data to concussion outcomes.

Neuroimaging of sport concussion: persistent alterations in brain structure and function at medical clearance

The medical decision of return to play (RTP) after a sport concussion is largely based on symptom status following a graded exercise protocol. However, it is currently unknown how objective markers of brain structure and function relate to clinical recovery. The goal of this study was to determine whether differences in brain structure and function at acute injury remain present at RTP. In this longitudinal study, 54 active varsity athletes were scanned using magnetic resonance imaging (MRI), including 27 with recent concussion, imaged at both acute injury and medical clearance, along with 27 matched controls. Diffusion tensor imaging was used to measure fractional anisotropy (FA) and mean diffusivity (MD) of white matter and resting-state functional MRI was used to measure global functional connectivity (Gconn). At acute injury, concussed athletes had reduced FA and increased MD, along with elevated Gconn; these effects remained present at RTP. Athletes who took longer to reach RTP also showed elevated Gconn in dorsal brain regions, but no significant white matter effects. This study presents the first evidence of altered brain structure and function at the time of medical clearance to RTP, with greater changes in brain function for athletes with a longer recovery time.

An investigation of neuroinjury biomarkers after sport-related concussion: from the subacute phase to clinical recovery

ABSTRACT Objectives: To characterise a panel of neuroinjury-related blood biomarkers after sport-related concussion (SRC). We hypothesised significant differences in biomarker profiles between athletes with SRC and healthy controls at both subacute and medical clearance time points. Methods: Thirty-eight interuniversity athletes were recruited over two athletic seasons (n = 19 SRC; n = 19 healthy matched-control). High-sensitivity immunoassay was used to evaluate 11 blood analytes at both the subacute phase after SRC and at medical clearance. Results: Univariate analysis identified elevated circulating peroxiredoxin-6 (PRDX-6) in athletes with SRC compared to healthy controls at the subacute time point. Multivariate analyses yielded similar results in the subacute phase, but identified both PRDX-6 and T-tau as significant contributors to class separation between athletes with SRC and controls at medical clearance. Conclusions: Our results are consistent with the increasing recognition that physiological recovery after SRC extends beyond clinical recovery. Blood biomarkers appear to be useful in elucidating the biology of brain restitution after SRC. However, their implementation requires mindfulness of factors such as academic stress, exercise, and injury heterogeneity.

Earlier time to aerobic exercise is associated with faster recovery following acute sport concussion

Objective To determine whether earlier time to initiation of aerobic exercise following acute concussion is associated with time to full return to (1) sport and (2) school or work. Methods A retrospective stratified propensity score survival analysis of acute (≤14 days) concussion was used to determine whether time (days) to initiation of aerobic exercise post-concussion was associated with, both, time (days) to full return to (1) sport and (2) school or work. Results A total of 253 acute concussions [median (IQR) age, 17.0 (15.0–20.0) years; 148 (58.5%) males] were included in this study. Multivariate Cox regression models identified that earlier time to aerobic exercise was associated with faster return to sport and school/work adjusting for other covariates, including quintile propensity strata. For each successive day in delay to initiation of aerobic exercise, individuals had a less favourable recovery trajectory. Initiating aerobic exercise at 3 and 7 days following injury was associated with a respective 36.5% (HR, 0.63; 95% CI, 0.53–0.76) and 73.2% (HR, 0.27; 95% CI, 0.16–0.45) reduced probability of faster full return to sport compared to within 1 day; and a respective 45.9% (HR, 0.54; 95% CI, 0.44–0.66) and 83.1% (HR, 0.17; 95% CI, 0.10–0.30) reduced probability of faster full return to school/work. Additionally, concussion history, symptom severity, LOC deleteriously influenced concussion recovery. Conclusion Earlier initiation of aerobic exercise was associated with faster full return to sport and school or work. This study provides greater insight into the benefits and safety of aerobic exercise within the first week of the injury.