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. 2023 Mar;33(1):122-143.
doi: 10.1007/s11065-022-09566-z. Epub 2022 Dec 12.

Diffusion Imaging of Sport-related Repetitive Head Impacts-A Systematic Review

Inga K Koerte  1   2   3 , Tim L T Wiegand  4   5 , Elena M Bonke  4   5   6 , Janna Kochsiek  4   5 , Martha E Shenton  5   7
Affiliations

Diffusion Imaging of Sport-related Repetitive Head Impacts-A Systematic Review

Inga K Koerte et al. Neuropsychol Rev. 2023 Mar.

Abstract

Repetitive head impacts (RHI) are commonly observed in athletes participating in contact sports such as American football, ice hockey, and soccer. RHI usually do not result in acute symptoms and are therefore often referred to as subclinical or "subconcussive" head impacts. Epidemiological studies report an association between exposure to RHI and an increased risk for the development of neurodegenerative diseases. Diffusion magnetic resonance imaging (dMRI) has emerged as particularly promising for the detection of subtle alterations in brain microstructure following exposure to sport-related RHI. The purpose of this study was to perform a systematic review of studies investigating the effects of exposure to RHI on brain microstructure using dMRI. We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) to determine studies that met inclusion and exclusion criteria across three databases. Seventeen studies were identified and critically evaluated. Results from these studies suggest an association between white matter alterations and RHI exposure in youth and young adult athletes. The most consistent finding across studies was lower or decreased fractional anisotropy (FA), a measure of the directionality of the diffusion of water molecules, associated with greater exposure to sport-related RHI. Whether decreased FA is associated with functional outcome (e.g., cognition) in those exposed to RHI is yet to be determined. This review further identified areas of importance for future research to increase the diagnostic and prognostic value of dMRI in RHI and to improve our understanding of the effects of RHI on brain physiology and microstructure.

Keywords: Chronic traumatic encephalopathy; Concussion; Contact sport; Diffusion magnetic resonance imaging; Header; Repetitive head impacts; Soccer; Youth athletes.

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Conflict of interest statement

Three of the studies included in this systematic review were authored by I. K. Koerte and M. E. Shenton.

Figures

Fig. 1
Fig. 1
Left: Coronal view of a color-coded diffusion tensor map (FA) with red representing left–right, blue representing superior-inferior, and green representing anterior–posterior direction of diffusion; Middle: Example of a coronal view of a Tract-Based Spatial Statistics (TBSS) white matter skeleton (green) and statistically significant differences in red-yellow clusters; Right: Example of a coronal view of tractography of the corpus callosum using a two-tensor algorithm
Fig. 2
Fig. 2
Literature search process
Fig. 3
Fig. 3
Overview of types of contact sport, types of control groups, mean age of participants, sample size, study design, and dMRI analysis technique of 17 included articles. TBSS Tract-Based Spatial Statistics, FA Fractional Anisotropy, ROI Region of Interest
See this image and copyright information in PMC

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