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Traumatic Brain Injury (TBI) is a significant public health and financial concern that is affecting tens of thousands of people in the United States annually. There were over a million hospital visits related to TBI in 2017. Along with immediate and short-term morbidity from TBI, chronic traumatic encephalopathy (CTE) can have life-altering, chronic morbidity, yet the direct linkage of how head impacts lead to this pathology remains unknown. A possible clue is that chronic traumatic encephalopathy appears to initiate in the depths of the sulci. The purpose of this study was to isolate the injury mechanism/s associated with blunt force impact events. To this end, drop tower experiments were performed on a human head phantom. Our phantom was fabricated into a three-dimensional extruded ellipsoid geometry made out of Polyacrylamide gelatin that incorporated gyri-sulci interaction. The phantom was assembled into a polylactic acid 3D-printed skull, surrounded with deionized water, and enclosed between two optical windows. The phantom received repetitive low-force impacts on the order of magnitude of an average boxing punch. Intracranial pressure profiles were recorded in conjunction with high-speed imaging, 25 k frames-per-second. Cavitation was observed in all trials. Cavitation is the spontaneous formation of vapor bubbles in the liquid phase resulting from a pressure drop that reaches the vapor pressure of the liquid. The observed cavitation was predominately located in the contrecoup during negative pressure phases of local intracranial pressure. To further investigate the cavitation interaction with the brain tissue phantom, a 2D plane strain computational model was built to simulate the deformation of gyrated tissue as a result from the initiation of cavitation bubbles seen in the phantom experiments. These computational experiments demonstrated a focusing of strain at the depths of the sulci from bubble expansion. Our results add further evidence that mechanical interactions could contribute to the development of chronic traumatic encephalopathy and also that fluid cavitation may play a role in this interaction., Competing Interests: JK, AW, MT, and RM-A are listed as inventors in a patent application for the Biofidelic Model of the Human Brain. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Kerwin, Yücesoy, Vidhate, Dávila-Montero, Van Orman, Pence, Tartis, Mejía-Alvarez and Willis.)

Comparing results across studies in traumatic brain injury (TBI) has been difficult because of the variability in data coding, definitions, and collection procedures. The global aim of the Working Group on Demographics and Clinical Assessment was to develop recommendations on the coding of clinical and demographic variables for TBI studies applicable across the broad spectrum of TBI, and to classify these as core, supplemental, or emerging. The process was consensus driven, with input from experts over a broad range of disciplines. Special consideration was given to military and pediatric TBI. Categorizing clinical elements as core versus supplemental proved difficult, given the great variation in types of studies and their interests. The data elements are contained in modules, which are grouped together in categories. Three levels of detail for coding data elements were developed: basic, intermediate, and advanced, with the greatest level of detail in the advanced version. In every case, the more detailed coding can be collapsed into the basic version. Templates were produced to summarize coding formats, motivation of choices, and recommendations for procedures. Work is ongoing to include more international participation and to provide an electronic data entry format with pull-down menus and automated data checks. This proposed standardization will facilitate comparison of research findings across studies and encourage high-quality meta-analysis of individual patient data., (Copyright © 2010 American Congress of Rehabilitation Medicine. Published by Elsevier Inc. All rights reserved.)