Journal of neurotrauma
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Journal of neurotrauma · Oct 2019
Diffusion Tensor Imaging in Athletes Sustaining Repetitive Head Impacts: A Systematic Review of Prospective Studies.
Competitive sport participation, in contact and collision sports, exposes athletes to repetitive head impacts. Although these impacts do not always result in overt symptomology or a diagnosed "concussion," evidence indicates that cumulative repetitive impacts affect brain pathophysiology. The purpose of this study was to perform a systematic review of prospective, longitudinal trials evaluating repetitive head impact exposure on white matter (WM) microstructure in collision and contact sport athletes to inform clinical care and treatment strategies. ⋯ The majority of studies demonstrated significant longitudinal changes in anisotropy and/or diffusivity metrics that were associated with the quantity and/or the magnitude of head impact exposure, highlighting the utility of diffusion tensor imaging (DTI) for measuring changes in WM microstructure. Our review also comments on study methodology and describes how age, sex, sport, and time between sport cessation and DTI measures contribute to divergent findings within the literature. Suggestions for future research are also provided to overcome previous study limitations and maximize our understanding of the role of repetitive head impact exposure on WM integrity and long-term neurological sequela.
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Journal of neurotrauma · Oct 2019
Handling of missing outcome data in traumatic brain injury research - a systematic review.
Traumatic brain injury (TBI) research commonly measures long-term functional outcome, but studies often suffer from missing data as patients are lost to follow-up. This review assesses the extent and handling of missing outcome data in the TBI literature and provides a practical guide for future research. Relevant electronic databases were searched from January 1, 2012 to October 27, 2017 for TBI studies that used the Glasgow Outcome Scale or Glasgow Outcome Scale-Extended (GOS/GOSE) as an outcome measure. ⋯ Of 139 studies that did report missing outcome data, only 50% attempted to identify why data were missing, with just 4 reporting their assumption on the "missingness mechanism." The handling of missing data was heterogeneous, with the most common method being its exclusion from analysis. These results confirm substantial variability in the standard of reporting and handling of missing outcome data in TBI research. We conclude that practical guidance is needed to facilitate meaningful and accurate study interpretation, and therefore propose a framework for the handling of missing outcome data in future TBI research.