Head trauma in sports – clinical characteristics, epidemiology and biomarkers

Abstract

Traumatic brain injury (TBI) is clinically divided into a spectrum of severities, with mild TBI being the least severe form and a frequent occurrence in contact sports, such as ice hockey, American football, rugby, horse riding and boxing. Mild TBI is caused by blunt nonpenetrating head trauma that causes movement of the brain and stretching and tearing of axons, with diffuse axonal injury being a central pathogenic mechanism. Mild TBI is in principle synonymous with concussion; both have similar criteria in which the most important elements are acute alteration or loss of consciousness and/or post‐traumatic amnesia following head trauma and no apparent brain changes on standard neuroimaging. Symptoms in mild TBI are highly variable and there are no validated imaging or fluid biomarkers to determine whether or not a patient with a normal computerized tomography scan of the brain has neuronal damage. Mild TBI typically resolves within a few weeks but 10–15% of concussion patients develop postconcussive syndrome. Repetitive mild TBI, which is frequent in contact sports, is a risk factor for a complicated recovery process. This overview paper discusses the relationships between repetitive head impacts in contact sports, mild TBI and chronic neurological symptoms. What are these conditions, how common are they, how are they linked and can they be objectified using imaging or fluid‐based biomarkers? It gives an update on the current state of research on these questions with a specific focus on clinical characteristics, epidemiology and biomarkers.

Pupillary changes after clinically asymptomatic high-acceleration head impacts in high school football athletes

“…Numerous studies have recently shown that changes in biomarkers that occur with SRC may be useful for both diagnosis determination and return-to-play decisions. 1,31,32 However, biomarker analysis typically requires invasive methods of collection, advanced laboratory processing, or advanced imaging, which limits its utility in most athletic settings (e.g., high schools). Furthermore, there is now evidence of brain injury in athletes who are asymptomatic or do not otherwise seek immediate clinical attention.…”

Development and Validation of a High Sensitivity Assay for Measuring p217 + tau in Cerebrospinal Fluid

“…The higher levels of p217 + tau seen in amyloid positive dementia subjects versus amyloid negative dementia subjects suggests the p217 + tau assays may be selective for AD, in contrast to total tau assays that detect high signal in many neurodegenerative conditions (e.g., after acute brain injury [20,21]). To further evaluate the potential of the p217 + tau assays to identify amyloid positive subjects, a second clinical cohort was examined, this time of presymptomatic subjects in order to observe a different range of A␤ 42 and A␤ 40 levels (n = 184 subjects, 79% amyloid positive).…”

Chronic Traumatic Encephalopathy and the Built Environment

“…Chronic Traumatic Encephalopathy (CTE) was formally known as Dementia Pugilistica or punch drunk because the condition was rst identi ed in boxers, and the symptoms resembled intoxication (Zetterberg et al, 2019). Dementia Pugilistica suggests a relationship between CTE and other dementias such as Alzheimer's disease.…”