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Literature Summary

understanding The Problem 

Defining Sport Related Concussion (SRC) 

For the purposes of this investigation, we will adopt the definition of concussion as defined by the 2017 Concussion in Sport Group. Concussion is “… [a form of] traumatic brain injury induced by biomechanical forces” (1). The injury may result from “…a direct blow to the head, face, neck or elsewhere on the body with an impulsive force transmitted to the head”(1). SRC results in a short-lived neurological impairment with symptoms manifesting within four broad symptom categories: physical, cognitive, emotional and sleep-related disturbances (1). Symptoms may appear immediately following a suspected injury, with some individuals endorsing new symptoms hours or days later (2). In general, 80-90% of individuals will recover within 7 to 10 days. However, observed recovery trajectories are prolonged in both children and adolescent populations (3, 4); typical recovery timelines for these age groups fall around the 30-day mark (1). 



Persisting Post-Concussive Symptoms


Recent trends within SRC research have moved towards examining predictor variables associated with prolonged recovery or persistent post-concussion symptoms (PCS). A recent study conducted by Zemek et al. found that 39.9% of their concussed adolescent athlete sample met criteria for Post-Concussion Syndrome (i.e., presence of 3 or more symptoms persisting for more than 4 weeks following a suspected concussion)(5). Similar studies conducted using concussed pediatric and adolescent samples suggest incidence rates between 29% and 73% (6-8). Persistent PCS are associated with several negative outcomes. Although not exclusive to SRC or adolescents, persisting PCS have been associated with both disability and high health service use (9-12)as well as low levels of life satisfaction (13). Individuals who experience persisting symptoms may also be at risk for chronic headaches, vestibular dysfunction, aerobic deconditioning, mood disorders, social isolation as well as decreases in academic achievement (14-16). Symptoms persisting past the point of 3 months are thought to intensify the presence of any emotional or depressive symptoms (17). At this time, several modifiable (i.e., poor coping skills) and non-modifiable (i.e., age, sex) factors have been attributed to persistent PCS.



Predicting Recovery Following Injury


The use of multivariable prognostic models to predict recovery following head injury has become a prominent area of interest among SRC researchers (18); although a number of single variables have been isolated as significant predictors of outcome following head injury, multivariable models have been shown to provide more accurate estimates of clinical outcome (19). A systematic review conducted by Silverberg and colleagues in 2015 examined n=26 publications. Variables of interest were categorized as either pre-injury (i.e., age, sex, education, etc.), peri-injury (diagnosis, Glasgow Coma Scale score, amnesia at time of injury etc.), and early post-injury categories (symptom severity, performance on sensory motor tests, etc.). Results indicated that the predictive ability of the variables was inconsistent across the studies captured. However, the female sex, poor pre-injury mental health status, early post-injury cognitive impairment as well as acute psychological distress were associated with the poorest outcomes. Lifetime history of concussion has also been associated with protracted recovery from subsequent concussions, however the dose-response relationship has yet to be clearly established (20-23). With respect to youth, pre-injury factors were found to have the strongest effect on recovery (18). In conclusion, Silverberg et al. argued that the scientific community has yet to establish an adequate multivariable prognostic model for recovery following head injury (18). 

Mental Health & Recovery from SRC 

Psychiatric symptoms (i.e., depressive and anxiety symptoms) are among the most pervasive outcomes associated with SRC. However, incidence rates of depression following concussion among adolescent aged individuals has been inconsistent within the literature. One study (n=92; aged 7 to 18 years old) found that 22% of their sample self-reported significant depressive symptoms in the first six months following injury (24). Similar investigations pertaining to the same age group yielded rates of 11% (25)to 26% (26). On the contrary, a cohort of youth (aged 7 to 17 years old) whom was followed 1 to 3 years post-injury demonstrated a much lower incidence rate of depression (3%) (27). 


In respect to recovery, evidence suggests that SRC symptom resolution is further complicated by a pre- or co-morbid mood disorder diagnosis like depression, however most of these findings have been observed in adult samples (28-32). Few investigations have examined the impact of a mood disorder like depression prior to (i.e., pre-morbid) or simultaneous (i.e., co-morbid) to a SRC in adolescent athletes(6, 33). Of the investigations that did, findings indicated that individuals self-reporting pre-injury depression demonstrated longer recovery times, required lengthy school accommodations and demonstrated greater declines in school performance (6). Some literature has also indicated that post-concussion depressive symptoms are associated with an increase in suicide risk, poor functional outcomes, lower cognitive performance and reduced quality of life (34-38). Despite known implications of depressive symptoms for recovery from injury, concussion baseline or post-injury assessments do not typically assess or measure depressive or anxiety symptoms. Therefore, addressing excessive depressive or anxiety symptoms prior to or shortly after the occurrence of a SRC is of great advantage to an athlete at risk for SRC (i.e., individuals involved in high-speed contact and collision sports). 

Exploring Affective Solutions


Adopting a Biopsychosocial Approach


To achieve a better understanding of risk for delayed functional recovery (i.e., number of days from injury until return-to-play or school) and risk for developing a mood disorder following concussion, investigators should aim to understand concussed adolescent athletes from a biopsychosocial perspective; this perspective considers “biological, psychological and social factors and their complex interactions in understanding health and illness” (39). Use of a biopsychosocial framework encompasses a multi-systems, multi-method approach that extends beyond that of neurocognitive and psychiatric evaluations alone (40). In alignment with this perspective, investigators should strive to examine novel psychological (i.e., coping skills, identity, resilience, etc.) and social factors (i.e., socioeconomic status, presence of social support, etc.) as potential predictors of functional recovery following SRC. Investigations of this nature have been published extensively within the broader sport-injury literature; study findings have identified the importance of psychosocial factors such as motivation, self-esteem, optimism, life stress, anxiety and depression for both physical injury risk and rehabilitation outcomes (41). 

To better understand the relationship between proposed moderators (i.e., coping skills, and resilience, and motivation) in addition to other predictive factors (i.e., athletic identity, age, sex, history of concussion, etc.) in regard to functional recovery from concussion, we can refer to Wiese-Bjornstal and colleagues Integrated Model of Response to Sport Injury(42) (See Figure 1). This model illustrates the complex interplay that personal and situational factors have on the cognitive appraisal, emotional and behavioural response associated with sport injury. The program of research contained herein seeks to better understand how these relationships apply to recovery following concussion. 

Variable of Interest: Athletic Identity 


Athletic identity (AI) is defined as “the degree to which an individual identifies with an athlete role, and looks to others for acknowledgement of that role” (43). Seminal work conducted by Brewer et al. in this area of study has indicated that AI has been positively and consistently associated with depressive symptoms in adults following a sport-related injury (44). However, at least one study has indicated the contrary; mood disturbance persisted despite a high or low AI (45). Brewer concludes individuals whom hold a strong and exclusive AI are more likely to become depressed following injury as compared to their peers who identify less with an athlete role. Further “insult to injury” ensues among individuals who hold a higher AI (in conjunction with a higher gender role conflict) as they have also been found to hold negative views about seeking mental health help (46). It has also been postulated that individuals with a high AI are more likely to over adhere to prescribed rehabilitation programs and risk premature return to sport (47). 

In respect to SRC, injury is proposed to threaten a key aspect of the athlete’s defined self-schema (i.e., ability to participate in sport) (43, 48). They are unable to do, act, or fulfill the role they once did. One study of adolescent aged athletes (n=48, aged 15 to 18 years old) indicated that positive stress and AI were found to significantly predict depressive symptoms, irrespective of the individuals’ gender or injury severity(49). In this study, coping abilities did not significantly predict depressive symptoms. However, increased social support was significantly associated with decreased depressive symptom reporting (p<0.001). Conversely, identity confusion during adolescence has also been associated with reduced self-worth, anxiety, depression, and deviant behaviour (50). Overall, AI is thought to be a relatively stable trait thereby making it suitable to explore as a predictor of prognosis following SRC. However in the long-term, AI has been shown to decrease following an event that is perceived by the athlete as threatening, or to have impeded their ability to perform within that role. Threatening events may include a poor competitive season (51), deselection (i.e., being “cut” from the team) (52), or severe injury (48). Brewer further states that AI and identity foreclosure (i.e., low exploration of other identities and a high commitment to a given identity) within sport-based settings is most prominent during late adolescence (53). Sex differences have also been identified in AI during adolescence, with boys typically holding a higher AI than do girls of the same age (54). To that extent, it has also been proposed that the construction of AI may differ from one sex to the other (55). 

Within SRC literature, only one investigation has explored AI as a predictor of SRC symptom resolution (56). Using an adolescent athlete sample (n= 51), O’Rourke et al. identified a weak correlation between AI and PCS symptoms collected ~14-21 days post-injury (r= 0.29 ; p<0.05), and ~21-28 days post-injury (r=0.39; p<0.01). Within regression models (controlling for age, gender, number of days post-injury, and history of concussion within the last 12 months) AI remained a significant predictor of PCS severity at one month (r2=0.10,b= 0.32, F=5.10, p<0.05). Among a number of limitations present within this investigation (i.e., small sample size, undefined inclusion/exclusion criteria), authors did not assess or control for pre-injury mental health status (i.e., presence and severity of depressive or anxiety symptoms) or a lifetime history of concussion injury. The program of research presented within this application will address these short-comings and elaborate upon this work.

Contributing to the Literature

Findings from this investigation will be used to achieve a better understanding of the risk for delayed functional recovery and risk for persisting and problematic mental health symptoms (i.e., depressive and anxiety symptoms) following concussion among adolescent athletes.   



Findings from this investigation will be used to inform concussion management practices for injured adolescent athletes. For example, should pre- or co-morbid depressive or anxiety symptoms be found to contribute to delayed recovery of concussion symptoms, a proactive approach to addressing mental health concerns among adolescent athletes may be advantageous. Similarly, if a high AI is found to be deleterious to recovery following concussion, steps should be taken to help young athletes diversify their self-schema (i.e., shift their focus towards their role and impact as a student, sibling, volunteer, musician, etc.). One important assumption being made here is that bolstering/altering these constructs (i.e., an individual’s AI, coping skills, resilience and motivation) prior to injury will contribute to improvements in functional recovery following injury. Furthermore, adopting a holistic approach to establishing risk for prolonged functional recovery among adolescents will be useful for informing the athlete (and their families) of how their recovery may progress over time. The proposed mediators (i.e., psychological/cognitive appraisal) and moderators (i.e., resilience, coping skills, motivation, etc.) of SRC recovery have not been investigated to this extent within this population.