Salivary Biomarkers for Concussion

Concussion (CC) (also called mild head trauma), which accounts for 85% of all head injuries, is very common in professional and amateur athletes. CC is an injury to the brain resulting from the direct or indirect impact of external mechanical forces, momentarily disrupting its function on a cellular level. Unlike more serious head injury (moderate and severe), which can be diagnosed using neuroimaging techniques (CT, MRI, etc.), patients suffering from CC do not necessarily show visible signs of structural abnormalities. As a result, diagnosis of CC is offen difficult. It is essentially based on subjective observational criteria and on the determination of the Glasgow Coma Scale (GCS) score, a score of 13 to 15 indicating potential CC. In approximately 15% of cases, symptoms such as momentary loss of consciousness (less than 30 minutes), amnesia lasting less than 24 hours, neurological deficit, or convulsions can be used to make a diagnosis. In the majority of cases, concussion goes undetected and no specific treatment or rehabilitation is put in place. Recently, certain molecular biomarkers (BMs) of CC in elite athletes have been identified (Di Pietro et al. 2021; McCrea et al. 2020). However, the reference values of these BMs are not determined with sufficient robustness to enable the best use for concussion diagnostic tests. To detect these biomarkers, it is first necessary to determine their physiological profiles as well as the changes in intensity associated with intense physical efforts during training session and/or matches.