The Role of Pre-Season Health Characteristics as Injury Risk Factors in Female Adolescent Soccer Players

[Purpose] Determine if female adolescent soccer players with a history of concussion, impaired K-D scores, and pre-season subjective complaints of neck pain, dizziness, and headache were predisposed to additional risk of musculoskeletal or concussive injury during 10-weeks of competitive play. [Participants and Methods] Twenty-three female high school soccer athletes provided concussion history and reported pre-season subjective complaints. K-D testing was performed pre and postseason. During the 10-week season, all injuries, preventing participation in practice or game, were recorded. [Results] Six reported a history of concussion. Of those six, three injuries were reported, including two concussions and a hamstring strain. Baseline K-D scores were worse in athletes that had two or more pre-season subjective factors compared to those that did not have any. Moderate positive correlations were found between a history of concussion and the number of injuries and a history of concussion and K-D post-test scores. [Conclusion] Findings indicate that pre-season subjective factors of neck pain, dizziness and headache, history of concussion, and K-D potentially increased injury risk. Combining pre-season metrics both at baseline and during the course of the season may assist in better injury risk screening in-season or indicate suboptimal function due to cumulative effects

A Dose Relationship Between Brain Functional Connectivity and Cumulative Head Impact Exposure in Collegiate Water Polo Players.

A growing body of evidence suggests that chronic, sport-related head impact exposure can impair brain functional integration and brain structure and function. Evidence of a robust inverse relationship between the frequency and magnitude of repeated head impacts and disturbed brain network function is needed to strengthen an argument for causality. In pursuing such a relationship, we used cap-worn inertial sensors to measure the frequency and magnitude of head impacts sustained by eighteen intercollegiate water polo athletes monitored over a single season of play. Participants were evaluated before and after the season using computerized cognitive tests of inhibitory control and resting electroencephalography. Greater head impact exposure was associated with increased phase synchrony [r (16) > 0.626, p < 0.03 corrected], global efficiency [r (16) > 0.601, p < 0.04 corrected], and mean clustering coefficient [r (16) > 0.625, p < 0.03 corrected] in the functional networks formed by slow-wave (delta, theta) oscillations. Head impact exposure was not associated with changes in performance on the inhibitory control tasks. However, those with the greatest impact exposure showed an association between changes in resting-state connectivity and a dissociation between performance on the tasks after the season [r (16) = 0.481, p = 0.043] that could also be attributed to increased slow-wave synchrony [F (4, 135) = 113.546, p < 0.001]. Collectively, our results suggest that athletes sustaining the greatest head impact exposure exhibited changes in whole-brain functional connectivity that were associated with altered information processing and inhibitory control

Long-term health outcomes after exposure to repeated concussion in elite level: rugby union players

Background: There is continuing concern about effects of concussion in athletes, including risk of the neurodegenerative disease chronic traumatic encephalopathy. However, information on long-term health and wellbeing in former athletes is limited. Method: Outcome after exposure to repeated brain injury was investigated in 52 retired male Scottish international rugby players (RIRP) and 29 male controls who were similar in age and social deprivation. Assessment included history of playing rugby and traumatic brain injury, general and mental health, life stress, concussion symptoms, cognitive function, disability and markers of chronic stress (allostatic load). Results: The estimated number of concussions in RIRP averaged 14 (median=7; IQR 5-40). Performance was poorer in RIRP than controls on a test of verbal learning (p=0.022) and of fine co-ordination of the dominant hand (p=0.038) and not significantly different on other cognitive tests (p>0.05). There were no significant associations between number of concussions and performance on cognitive tests. Other than a higher incidence of cardiovascular disease in controls, no group differences were detected in general or mental health or estimates of allostatic load. In RIRP, persisting symptoms attributed to concussion were more common if reporting more than nine concussions (p=0.028), although these symptoms were not perceived to affect social or work functioning. Conclusions: Despite a high number of concussions in RIRP, differences in mental health, social or work functioning were not found late after injury. Subtle group differences were detected on two cognitive tests, the cause of which is uncertain. Prospective group comparison studies on representative cohorts are required

Disrupted White Matter Microstructure of the Cerebellar Peduncles in Scholastic Athletes After Concussion.

Concussion, or mild traumatic brain injury (mTBI), is a major public health concern, linked with persistent post-concussive syndrome, and chronic traumatic encephalopathy. At present, standard clinical imaging fails to reliably detect traumatic axonal injury associated with concussion and post-concussive symptoms. Diffusion tensor imaging (DTI) is an MR imaging technique that is sensitive to changes in white matter microstructure. Prior studies using DTI did not jointly investigate white matter microstructure in athletes, a population at high risk for concussive and subconcussive head traumas, with those in typical emergency room (ER) patients. In this study, we determine DTI scalar metrics in both ER patients and scholastic athletes who suffered concussions and compared them to those in age-matched healthy controls. In the early subacute post-concussion period, athletes demonstrated an elevated rate of regional decreases in axial diffusivity (AD) compared to controls. These regional decreases of AD were especially pronounced in the cerebellar peduncles, and were more frequent in athletes compared to the ER patient sample. The group differences may indicate differences in the mechanisms of the concussive impacts as well as possible compound effects of cumulative subconcussive impacts in athletes. The prevalence of white matter abnormality in cerebellar tracts lends credence to the hypothesis that post-concussive symptoms are caused by shearing of axons within an attention network mediated by the cerebellum, and warrant further study of the correlation between cerebellar DTI findings and clinical, neurocognitive, oculomotor, and vestibular outcomes in mTBI patients

Task-dependent Modulation of Cortical Excitability and Balance Control in Individuals with Post-concussion Syndrome

In most cases, symptoms resolve between 7-10 days post-concussion. However, in 10-15% of the concussed population, symptoms can remain unresolved for months to years following the head injury. The purpose of this thesis was two-fold, and was broken up into two studies, where the same individuals participated in both studies. The purpose of the first study was to quantify the differences in balance control between individuals with PCS (i.e., had been experiencing symptoms for \u3c30 days) and non-concussed individuals during a lower-limb reaching task. Participants completed a static balance assessment before and after a lower-limb reaching task, which incorporated a Go/No-Go paradigm. Results from this study revealed no differences in the static stability assessments, however, individuals with PCS demonstrated increased medial-lateral COP displacement as well as greater trunk pitch during the reaching task. Overall, the findings reveal persistent balance impairments in individuals with PCS, which may put this population at an increased risk of further injury. The purpose of the second study was to assess task-dependent modulation of cortical excitability prior to planned index finger abduction contractions comparing a non-concussed population to a population with PCS. The protocol in this study consisted of both single and paired-pulse transcranial magnetic stimulation (TMS) which was applied prior to the beginning of 3 different tasks (i.e., a rest condition with no plan to contract, a precision contraction, and a powerful contraction). In addition to the three tasks, participants also had to respond to a Go/No-Go cue. The results of this study revealed an increase in excitability prior to a precision contraction in both non-concussed and PCS groups. No differences in task-dependent modulation were found between the two groups with respect to intracortical facilitation and inhibition, however a negative correlation between number of symptoms reported (SCAT3 symptom evaluation) and intracortical facilitation was revealed. The increase in corticospinal excitability prior to a precision contraction was not explained by the two cortical mechanisms we assessed and may therefore be due to spinal modulation or a different cortical mechanism. Overall, based on the results from this thesis, it appears that individuals with PCS have balance impairments, which may be a result of an inability to maximally activate their postural muscles. Furthermore, it appears that those individuals who reported a higher number of symptoms had greater reductions in intracortical facilitation, likely reflecting the heterogeneity of this clinical group

Neurocognitive findings in adults who played youth football

Chronic Traumatic Encephalopathy (CTE) has been linked to contact sports, most notably boxing and American football, due to their propensity for repetitive head impacts. Concerns in the community for the safety of athletes in all contact sports has driven a significant amount of research into concussions, their long term effects, and strategies for treatment and prevention. Knowledge of long term brain health in response to neurotrauma is limited, a gap especially noticeable in the literature on non-catastrophic brain injuries sustained as a child. Concussion is a common injury that is often self-resolving with no lasting neurologic or cognitive deficits. Although repetitive brain trauma is hypothesized to be necessary and sufficient to lead to CTE, no human or animal models have definitively demonstrated the pathophysiologic connection or confirmed the mechanism of symptoms. The research to date has been case based, lacking prospective cohorts, with data complicated by convenience sampling. These factors limit the generalizability of conclusions. CTE is neuropathologically defined with variable symptoms; however, it is only diagnosable at postmortem autopsy making the etiology and prevalence difficult to understand. As more research is published to understand if there is an association between a neurocognitive degenerative disease and contact sports, the concentration is on professional athletes. Yet professional athletes do not represent the overwhelming majority of all contact sport participants. The proposed study will compare adults who participated in youth football, but not beyond the high school level, to a control group of adults who did not play contact sports. Evaluating their cognitive function with an online assessment, the Behavior Rating Inventory of Executive Function – Adult Version (BRIEF-A), data will be analyzed for signs of clinical cognitive impairment. The objective is to measure adults who represent the high percentage of youth football players who do not continue to the advanced levels. Data obtained from this study will help communities make informed decisions, and create the foundation for future studies on long term benefits and risks of contact sports for children

Quantifying cognitive function in concussed athletes before and after acute exercise using a choice reaction time task

Following a concussion, cognitive deficits have been shown to last longer than symptom resolution. Currently clinicians rely heavily on symptom emergence following the fundamental exercises of the return to play (RTP) protocol, which may leave athletes at risk of returning to play too early if cognitive deficits have not been detected. The purpose of this study was to assess the effects of exercise on choice reaction time (CRT) both at rest and following an acute exercise in 3 populations: non-concussed (NC), recently concussed (RC), and post-concussion syndrome (PCS) individuals. A CRT task in the form of an iPad application measured each individual’s decision-making capabilities at four blocks: (1) 10 minutes prior to exercise, (2) Immediately prior to exercise, (3) immediately post exercise, and (4) 5 minutes post exercise. Participants were also fitted with an eye-tracking system during CRT task performance at rest in order to assess higher levels of cognitive processing. Results demonstrated a facilitative effect of learning and exercise arousal on CRT task performance in both NC and PCS but not in RC. Average RT in RC was not significantly different from NC while average RT in PCS was found to be significantly higher than NC. Gaze behaviour was significantly worse in PCS compared to NC while RC and NC were not significantly different. The absence of symptoms does not inherently mean that cognitive performance under acute physical stress has completely recovered in recently concussed individuals. On the other hand, PCS individuals continue to experience concussion-related symptoms, but appear to display partially recovered cognitive performance. Findings from the current study encourage the use of cognitive assessments following acute exercise during the RTP protocol in order to detect possibly lingering cognitive deficits

The effects of level and duration of play on cognition, mood and behavior among former football players

Thesis (M.A.)--Boston UniversityInterest in the short and long-term effects of concussions has drastically increased due to the recent high-profile deaths of former National Football League (NFL) players. However, research on this subject, especially at the youth level, has moved at a much slower rate. Second Impact Syndrome (SIS), Postconcussive Syndrome (PCS) and Chronic Traumatic Encephalopathy (CTE) are three major consequences that have the potential to negatively affect athletes participating in contact sports immediately or years after their athletic careers are over. The goal of this study is to examine whether the level of first exposure and/or duration of exposure has an effect on a player’s cognition, mood and behavior years after his football career is complete. I hypothesized that the age of onset of exposure to football would have a significant effect on cognition, mood and behavior later in life, and that those who started playing football prior to high school would self-report more problems in all three domains compared to those who started playing in high school when matched for the total number of years played. In order to test my hypotheses, analysis was completed on n=154 cases, all of whom played football at some level. Results showed that age of onset of exposure to football did have a significant effect on the Behavior Rating Inventory of Executive Function-Adult Version (BRIEF-A) assessment, specifically the Global Executive Composite (GEC) (p = .018), Behavioral Regulation Index (BRI) (p = .014) scores and three of the nine clinical subscales (Inhibit [p = .025], Shift [p = .015] and Self-Monitor [p = .048]). Age of onset of exposure to football was also found significant for the mood and behavior assessment scores, the Apathy Evaluation Scale (AES) (p = .024) and Center for Epidemiological Studies Depression Scale CES-D (p = .011). No significant difference in assessment scores was found for level of onset of exposure when matched by number of years of football played. BRIEF-A GEC, BRI and MI raw scores were significantly different than published normative data for each age group, except the 70-79 and 80-90 year olds, both of which had very small sample sizes. Significant differences in all BRIEF-A index scores and all nine clinical subscores were found for the 40-49, 50-59 and 60-69 age groups. Finding significant differences in these age groups is somewhat unsurprising, given that CTE symptoms tend to begin decades after the end of exposure. Also consistent with this idea, the 30-39 years old age group showed a significant difference with the normative data in six of the nine clinical subscales, while the 18-29 years old age group showed a significant difference in three of the nine subscales. Longitudinal studies will need to be conducted to validate these findings and further understand the relationship between level of onset of play and long-term deleterious effects as a result of repetitive brain trauma (RBT)

Descriptive Analysis of a Baseline Concussion Battery Among U.S. Service Academy Members: Results from the Concussion Assessment, Research, and Education (CARE) Consortium

Introduction The prevalence and possible long-term consequences of concussion remain an increasing concern to the U.S. military, particularly as it pertains to maintaining a medically ready force. Baseline testing is being used both in the civilian and military domains to assess concussion injury and recovery. Accurate interpretation of these baseline assessments requires one to consider other influencing factors not related to concussion. To date, there is limited understanding, especially within the military, of what factors influence normative test performance. Given the significant physical and mental demands placed on service academy members (SAM), and their relatively high risk for concussion, it is important to describe demographics and normative profile of SAMs. Furthermore, the absence of available baseline normative data on female and non-varsity SAMs makes interpretation of post-injury assessments challenging. Understanding how individuals perform at baseline, given their unique individual characteristics (e.g., concussion history, sex, competition level), will inform post-concussion assessment and management. Thus, the primary aim of this manuscript is to characterize the SAM population and determine normative values on a concussion baseline testing battery. Materials and Methods All data were collected as part of the Concussion Assessment, Research and Education (CARE) Consortium. The baseline test battery included a post-concussion symptom checklist (Sport Concussion Assessment Tool (SCAT), psychological health screening inventory (Brief Symptom Inventory (BSI-18) and neurocognitive evaluation (ImPACT), Balance Error Scoring System (BESS), and Standardized Assessment of Concussion (SAC). Linear regression models were used to examine differences across sexes, competition levels, and varsity contact levels while controlling for academy, freshman status, race, and previous concussion. Zero inflated negative binomial models estimated symptom scores due to the high frequency of zero scores. Results Significant, but small, sex effects were observed on the ImPACT visual memory task. While, females performed worse than males (p < 0.0001, pη2 = 0.01), these differences were small and not larger than the effects of the covariates. A similar pattern was observed for competition level on the SAC. There was a small, but significant difference across competition level. SAMs participating in varsity athletics did significantly worse on the SAC compared to SAMs participating in club or intramural athletics (all p’s < 0.001, η2 = 0.01). When examining symptom reporting, males were more than two times as likely to report zero symptoms on the SCAT or BSI-18. Intramural SAMs had the highest number of symptoms and severity compared to varsity SAMs (p < 0.0001, Cohen’s d < 0.2). Contact level was not associated with SCAT or BSI-18 symptoms among varsity SAMs. Notably, the significant differences across competition level on SCAT and BSI-18 were sub-clinical and had small effect sizes. Conclusion The current analyses provide the first baseline concussion battery normative data among SAMs. While statistically significant differences may be observed on baseline tests, the effect sizes for competition and contact levels are very small, indicating that differences are likely not clinically meaningful at baseline. Identifying baseline differences and significant covariates is important for future concussion-related analyses to inform concussion evaluations for all athlete levels