Sport-Related Concussion

see http://www.ncbi.nlm.nih.gov/pmc/articles/PMC522153/

A comprehensive understanding of concussion and its related risks is important in making return to play guidelines as well as health care and league policy ¹⁾.

Concussions are mild traumatic brain injuries. They occur in a wide range of sports and affect all athletes, from professional players to little leaguers.

Sports concussion has become a significant problem. In recent years, it has made headlines with reports about the consequences of returning to play too soon, as well as research findings into the long-term effects of the injury.

Sports-related concussions among youth athletes represent a significant public health concern, and neurocognitive testing is a method to evaluate the severity of cognitive impairment and recovery after a sports-related concussion.

10% of head and spinal injuries are a result of a sports-related event ²⁾ especially in contact sports such as hockey.

The Centers for Disease Control and Prevention estimate that approximately 1.6 million to 3.8 million sports-related concussions occur annually in the United States, although the true incidence is probably much higher. Under-reporting may be due to the fact that athletes, coaches, trainers, family and even some health care professionals are unaware of the symptoms and treatment options for concussion. And athletes who experience concussion sometimes fail to report their symptoms to avoid losing playing time.

Concussions that are unrecognized or are mismanaged put athletes at considerable risk of potentially catastrophic sequelae from re-injury. Repetitive head trauma from participation in contact sports such as boxing, football and ice hockey can lead to a permanent decrease in brain function.

Nearly half of all motocross competitors under the age of 18 reported concussion symptoms. Preventive measures are necessary to limit the negative impact from concussions. The risk of concussive injury can be decreased for pediatric motocross riders if they receive professional help with proper helmet fitting and through implementation of stricter guidelines regarding sponsorship ³⁾.

American football player

The symptoms of youth concussion are subtle and vary from athlete to athlete. The most common symptom is headache.

Each concussion presents in a unique manner, and it is well established that a concussion does not require a loss of consciousness. Furthermore, a brief loss of consciousness does not provide any information regarding concussion severity. What clinicians need to remember is that if an athlete sustains a blow to the body or head and post-concussive symptoms subsequently develop, by definition, that athlete has sustained a concussion.

see Concussion clinical features.

Neck pain in a concussion population is an emerging area of study that has been shown to have a negative influence on recovery. This effect has not yet been studied in collegiate athletes.

Hypothesis: New or worsened neck pain is common after a concussion (>30%), negatively influences recovery, and is associated with patient sex and level of contact in sport.

Study design: Cohort study; Level of evidence, 2.

Methods: Varsity-level athletes from 29 National Collegiate Athletic Association member institutions as well as nonvarsity sport athletes at military service academies were eligible for enrollment. Participants completed a preseason baseline assessment and follow-up assessments at 6 and 24 to 48 hours after a concussion, when they were symptom-free, and when they returned to unrestricted play. Data collection occurred between January 2014 and September 2018.

Results: A total of 2163 injuries were studied. New or worsened neck pain was reported with 47.0% of injuries. New or worsened neck pain was associated with patient sex (higher in female athletes), an altered mental status after the injury, the mechanism of injury, and what the athlete collided with. The presence of new/worsened neck pain was associated with delayed recovery. Those with new or worsened neck pain had 11.1 days of symptoms versus 8.8 days in those without (P < .001). They were also less likely to have a resolution of self-reported symptoms in ≤7 days (P < .001). However, the mean duration of the return-to-play protocol was not significantly different for those with new or worsened neck pain (7.5 ± 7.7 days) than those without (7.4 ± 8.3 days) (P = .592).

This novel study shows that neck pain was common in collegiate athletes sustaining a concussion, was influenced by many factors, and negatively affected recovery. ⁴⁾

see Sports related concussion diagnosis.

Sport-Related Concussion treatment.

Postconcussion syndrome

Permanent decrease in brain function, including:

Memory loss

Early Alzheimer's disease

Movement disorders such as parkinsonism

Emotional disturbances

The most notable complication of concussion is second impact syndrome.

Mayers, collected and analyzed data for all student-athletes diagnosed with concussion between 1998 and 2011. Outcome measurements were post-concussion symptom duration, time interval until return-to-play, and clinical outcomes self-reported by athletes and by athlete's parent/guardian 1 year post-injury. A total of 98 concussions occurred in 95 student athletes among a cohort averaging 350 athletes competing yearly. Athletes were managed according to expert-consensus guidelines. Forty-one (43%) of the athletes had experienced a previously-diagnosed concussion (range: 1-3). Eight athletes (10.4%), retired from their sport for concussion-related issues. Six athletes (6.3%) with completed follow-up experienced memory and/or concentration impairment(s) lasting more than 1 year ⁵⁾.

The research-based recommendations made for football between 1976 and 1980 resulted in a significant reduction in the incidence of fatalities and nonfatal catastrophic injuries. In 1968, 36 brain and cervical spine fatalities occurred in high school and collegiate football. The number had dropped to zero in 1990 and has averaged about 5 per year since then ⁶⁾.

In the 2014 World Cup, concussion assessment protocols were not followed in 63% of events when players involved in head collisions were not assessed by sideline health care personnel.

The 81 head collision events identified in this analysis are more than the 19 injuries to the head reported by team physicians to FIFA; however, the lack of formal assessments, identification of the players involved, and differences in methods preclude direct comparison between the studies. Team physicians may have only reported the most obvious and more severe events, and players may have underreported their symptoms to physicians to avoid losing playing time. The estimate from this study could also be underestimated because video footage follows the play and some injuries could have been missed.

Observation of players’ reactions to collision events does not necessarily mean injury or concussion occurred. Some may exaggerate or feign injury to draw a foul. However, 83% of observations noted players displaying more than 1 concussion sign.

Applying similar visible signs of concussion with support from video footage, the National Hockey League and the National Football League introduced trained spotters to identify potentially concussed athletes at games and remove players for assessment. Following the 2014 tournament, FIFA instituted a new rule that avoids disadvantaging teams with 1 less player during the assessment, which may improve the rate of appropriate assessments.

Soccer players presenting signs of concussion following a head collision event deserve assessment from independent health care personnel to avoid delay of care or further injury. Assessment and management of soccer players suspected of concussion should be improved ⁷⁾.

Merchant-Borna et al., conducted a prospective study to identify genome-wide changes in peripheral gene expression before and after sports-related concussion (SRC). A total of 253 collegiate contact athletes underwent collection of peripheral blood mononuclear cells (PBMCs) before the sport season (baseline). Sixteen athletes who subsequently developed an SRC, along with 16 non-concussed teammate controls, underwent repeat collection of PBMCs within 6 h of injury (acutely). Concussed athletes underwent additional sample collection at 7 days post-injury (sub-acutely). Messenger RNA (mRNA) expression at baseline was compared with mRNA expression acutely and sub-acutely post-SRC. To estimate the contribution of physical exertion to gene changes, baseline samples from athletes who subsequently developed an SRC were compared with samples from uninjured teammate controls collected at the acute time-point. Clinical outcome was determined by changes in post-concussive symptoms, postural stability, and cognition from baseline to the sub-acute time-point. SRC athletes had significant changes in mRNA expression at both the acute and sub-acute time-points. There were no significant expression changes among controls. Acute transcriptional changes centered on interleukins 6 and 12, toll-like receptor 4, and NF-κB. Sub-acute gene expression changes centered on NF-κB, follicle stimulating hormone, chorionic gonadotropin, and protein kinase catalytic subunit. All SRC athletes were clinically back to baseline by Day 7. In conclusion, acute post-SRC transcriptional changes reflect regulation of the innate immune response and the transition to adaptive immunity. By 7 days, transcriptional activity is centered on regulating the hypothalamic-pituitary-adrenal axis. Future efforts to compare expressional changes in fully recovered athletes with those who do not recover from SRC could suggest putative targets for therapeutic intervention ⁸⁾.

Concussion prevalence in Sport is well-recognized.

The cumulative effects of repetitive subclinical head impacts during sports may result in chronic white matter (WM) changes and possibly, neurodegenerative sequelae.

Sports related traumatic brain injury (TBI) is an important public health concern that is increasingly in the spotlight of both the lay press and the general public. Recent estimates suggest that 300,000 to 3.8 million sports-related TBIs occur in the United States annually.

Sports- and recreation-related traumatic brain injuries (SRR-TBIs) are a growing public health problem affecting persons of all ages in the United States.

OBJECTIVE:

To describe the trends of SRR-TBIs treated in US emergency departments (EDs) from 2001 to 2012 and to identify which sports and recreational activities and demographic groups are at higher risk for these injuries.

DESIGN:

Data on initial ED visits for an SRR-TBI from the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP) for 2001-2012 were analyzed.

SETTING:

NEISS-AIP data are drawn from a nationally representative sample of hospital-based EDs.

PARTICIPANTS:

Cases of TBI were identified from approximately 500,000 annual initial visits for all causes and types of injuries treated in EDs captured by NEISS-AIP.

MAIN OUTCOME MEASURE(S):

Numbers and rates by age group, sex, and year were estimated. Aggregated numbers and percentages by discharge disposition were produced.

RESULTS:

Approximately 3.42 million ED visits for an SRR-TBI occurred during 2001-2012. During this period, the rates of SRR-TBIs treated in US EDs significantly increased in both males and females regardless of age (all Ps < .001). For males, significant increases ranged from a low of 45.8% (ages 5-9) to a high of 139.8% (ages 10-14), and for females, from 25.1% (ages 0-4) to 211.5% (ages 15-19) (all Ps < .001). Every year males had about twice the rates of SRR-TBIs than females. Approximately 70% of all SRR-TBIs were reported among persons aged 0 to 19 years. The largest number of SRR-TBIs among males occurred during bicycling, football, and basketball. Among females, the largest number of SRR-TBIs occurred during bicycling, playground activities, and horseback riding. Approximately 89% of males and 91% of females with an SRR-TBI were treated and released from EDs.

CONCLUSION AND RELEVANCE:

The rates of ED-treated SRR-TBIs increased during 2001-2012, affecting mainly persons aged 0 to 19 years and males in all age groups. Increases began to appear in 2004 for females and 2006 for males. Activities associated with the largest number of TBIs varied by sex and age. Reasons for the reported increases in ED visits are unknown but may be associated with increased awareness of TBI through increased media exposure and from campaigns, such as the Centers for Disease Control and Prevention's Heads Up. Prevention efforts should be targeted by sports and recreational activity, age, and sex ⁹⁾.

Research into sport-related concussion (SRC) has grown substantially over the past decade, yet no authors to date have synthesized developments over this critical time period.

Eagle et al. from Pittsburgh published a network analysis approach in evaluating trends in the Sport-Related Concussion literature using a comprehensive search of original, peer-reviewed research articles involving human participants published between January 1, 2010, and December 15, 2019.

Design: Narrative review.

Main outcome measure(s): Bibliometric maps were derived from a comprehensive search of all published, peer-reviewed SRC articles in the Web of Science database. A clustering algorithm was used to evaluate associations among journals, organizations or institutions, authors, and keywords. The online search yielded 6130 articles, 528 journals, 7598 authors, 1966 organizations, and 3293 keywords.

The analysis supported 5 thematic clusters of journals: (1) biomechanics/sports medicine (n = 15), (2) pediatrics/rehabilitation (n = 15), (3) neurotrauma/neurology/neurosurgery (n = 11), (4) general sports medicine (n = 11), and (5) neuropsychology (n = 7). The analysis identified 4 organizational clusters of hub institutions: (1) University of North Carolina (n = 19), (2) University of Toronto (n = 19), (3) University of Michigan (n = 11), and (4) University of Pittsburgh (n = 10). Network analysis revealed 8 clusters for SRC key words, each with a central topic area: (1) epidemiology (n = 14), (2) rehabilitation (n = 12), (3) biomechanics (n = 11), (4) imaging (n = 10), (5) assessment (n = 9), (6) mental health/chronic traumatic encephalopathy (n = 9), (7) neurocognition (n = 8), and (8) symptoms/impairments (n = 5).

The findings suggest that during the past decade SRC research has (1) been published primarily in sports medicine, pediatric, and neuro-focused journals, (2) involved a select group of researchers from several key institutions, and (3) concentrated on new topical areas, including treatment or rehabilitation and mental health ¹⁰⁾.