Salivary MicroRNA as a Concussion Biomarker and the Implications for Athletic Trainers\u27 Practices

Many concussions are sustained globally each year; however, research suggests that a large number may go undiagnosed due to a reliance on subjective information from patients and limitations of current objective measures. Recently, efforts have been focused on identifying clinical biomarkers of concussions, including salivary microRNA (miRNA), to improve healthcare professionals’ concussion management practices. Even if salivary miRNA were shown to be a valid and reliable measure for managing concussions, healthcare professionals, such as athletic trainers (ATs), must be familiar with the tool and have positive attitudes toward the implementation into clinical practice. Therefore, the purpose of this dissertation was to better understand salivary miRNA as a concussion biomarker through three studies. In our first study, we performed a scoping review to identify specific salivary miRNA that have demonstrate potential in acting as a diagnostic or prognostic indicator of concussions. Overall, we found forty-nine salivary miRNA across nine studies throughout the literature. Of those forty-nine, thirty-four show potential for being a concussion diagnostic marker and twenty-one correlated to multiple concussions or symptom trends. Of those identified, five were identified in multiple studies. As previously stated, even if identified as a valid and reliable tool for concussion management, healthcare professionals such as ATs should demonstrate familiarity with these tools and show positive attitudes toward the implementation into clinical practice. Therefore, the second study of this dissertation aimed to evaluate ATs familiarity with biomarkers of concussion and their attitudes toward the future implementation into clinical practice. Overall, the results of this study indicated that ATs self-reported a lack of familiarity with current literature surrounding the use of biomarkers for concussion management but a large majority self-reported positive attitudes towards the future implementation of such a tool into clinical practice. Lastly, to address a limitation for the application of salivary miRNA as a concussion biomarker, we aimed to evaluate the effects of one NCAA Division I football season. In this study, we found that although simple inferential statistics revealed no significant differences between pre- and post-season expression of salivary miRNA, further analysis through intraclass correlation coefficient statistics revealed a lack of reliability in each of the six target salivary miRNA. Although these target miRNA did not demonstrate reliability from pre- to post-season, sub-analyses revealed a ratio of two miRNA that showed high sensitivity when identifying concussed individuals. Overall, research should continue to evaluate the potential for salivary miRNA to act as a concussion biomarker by evaluating other target miRNA