REPIMPACT - a prospective longitudinal multisite study on the effects of repetitive head impacts in youth soccer

Abstract

Repetitive head impacts (RHI) are common in youth athletes participating in contact sports. RHI differ from concussions; they are considered hits to the head that usually do not result in acute symptoms and are therefore also referred to as "subconcussive" head impacts. RHI occur e.g., when heading the ball or during contact with another player. Evidence suggests that exposure to RHI may have cumulative effects on brain structure and function. However, little is known about brain alterations associated with RHI, or about the risk factors that may lead to clinical or behavioral sequelae. REPIMPACT is a prospective longitudinal study of competitive youth soccer players and non-contact sport controls aged 14 to 16 years. The study aims to characterize consequences of exposure to RHI with regard to behavior (i.e., cognition, and motor function), clinical sequelae (i.e., psychiatric and neurological symptoms), brain structure, function, diffusion and biochemistry, as well as blood- and saliva-derived measures of molecular processes associated with exposure to RHI (e.g., circulating microRNAs, neuroproteins and cytokines). Here we present the structure of the REPIMPACT Consortium which consists of six teams of clinicians and scientists in six countries. We further provide detailed information on the specific aims and the design of the REPIMPACT study. The manuscript also describes the progress made in the study thus far. Finally, we discuss important challenges and approaches taken to overcome these challenges.

Keywords: Repetitive head impacts; Soccer; Sport-related brain injury; Youth athletes.

Fig. 1

REPIMPACT aims to characterize between-group differences in behavior, clinical sequelae, molecular processes, as well as neuroimaging measures of brain biochemistry, brain connectivity, and brain structure

Fig. 2

Overview of tested and included participants at the three timepoints at all data acquisition sites. Abbreviations. SOC = soccer players, CON = control athletes, GER = Germany, BEL = Belgium, NOR = Norway, TP1 = first assessment, TP2 = second assessment, TP3 = third assessment

Fig. 3

The REPIMPACT imaging protocol includes sequences for the acquisition of structural, diffusion and function MRI data. Sequences were designed to be as similar as possible across sites and scanners. Imaging analyses include segmentation and parcellation of structural data, diffusion measures, structural and functional connectivity analyses as well as MR spectroscopy