Factors influencing mouthguard effect on head acceleration: a scoping review

Background: Sport-related concussion (SRC) is a form of mild traumatic brain injury, mainly affecting those in contact and collision sports. Head acceleration is an important biomechanical determinant of SRC risk. Although mouthguards have been proposed as a protective device capable of attenuating head acceleration, the evidence base is methodologically heterogeneous, spanning diverse study designs, populations, impact protocols, and measurement technologies, making quantitative synthesis premature. Objective: To explore the extent, range, and nature of evidence on the use of mouthguards in relation to head acceleration outcomes during sport-related impacts and laboratory simulations. This scoping review will address the following sub-questions: What evidence exists that informs of the influence of mouthguard use on quantitative head acceleration outcomes in sport and laboratory settings? What device- and individual-specific factors have been reported as modifiers in relation to head acceleration and how do they impact head acceleration outcomes? Inclusion: Human adults aged 18 years or older, of any sex, participating in sport, physical activity, or a laboratory impact or perturbation protocol. Simulation based studies will be included provided that the model is representative of adult human anatomy and biomechanics. Studies involving mixed age cohorts will be included if data for adults can be identified separately. All empirical study designs will be considered, including randomised controlled trials (parallel and crossover), non-randomised controlled studies, observational studies (cohort, cross-sectional, case series), descriptive and pilot studies, and mixed-methods studies. Grey literature sources including theses and dissertations, technical reports, and registered study protocols will also be eligible. For conference abstracts, authors will be contacted for complete study results. Narrative reviews, systematic reviews, qualitative studies, and opinion pieces will be excluded from the review but will be hand-searched for additional primary sources. Methods: Nine electronic databases will be searched from inception. Two independent reviewers will screen records and chart data using Covidence, in accordance with the Joanna Briggs Institute (JBI) scoping review framework. Results will be reported following PRISMA-ScR.