| 1. |
- Antona, Jacobo, 1981, et al.
(författare)
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Belted Female Occupants in Frontal Car Crashes are More Likely to Sustain Moderate Concussions than Male Occupants
- 2017
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Ingår i: The Stapp Car Crash Conference 2017.
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Konferensbidrag (refereegranskat)abstract
- NASS-CDS data from years 2005-2015 was analyzed to estimate the frequency and risk of moderate and serious concussion injuries sustained by belted occupants in car crashes in the US. The concussion data was compared to all other brain injuries of higher severity and analyzed considering crash severity, crash year, car model year, and the victim’s age and sex. The results showed that an annual average estimation of 18,359 ±4,721 belted occupants sustained a concussion in the US, which comprises 84.7% of all occupants with MAISbrain2+ injury. After controlling for crash severity, female occupants in frontal crashes were estimated to be 1.4 times more likely to sustain a concussion than male occupants. As new strategies for the prevention of brain injuries are developed, this study suggests the need to incorporate moderate concussion injuries, with particular attention to female occupants.
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| 2. |
- Antona, Jacobo, 1981, et al.
(författare)
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Correlation of Global Head and Brain Tissue Injury Criteria to Experimental Concussion derived from Monkey Head Trauma Experiments
- 2013
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Ingår i: IRCOBI Conference. - 2235-3151. ; :IRC-13-55, s. 509-522
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Konferensbidrag (refereegranskat)abstract
- A series of 24 frontal head traumatic impacts on macaques carried out in the past were simulatedwith a validated finite element model of the specimens. From these simulations, brain tissue response and headaccelerations were extracted. Based on the accelerations, global head injury criteria were calculated.Correlation between the brain tissue mechanical parameters, the global head injury criteria and the concussionscored in the experiments were analyzed. Based on this analysis, global head injury criteria that best correlatewith concussion score for frontal impacts were identified and injury risk functions for brain tissue that can beused for human FE models are proposed. In addition, the new results were compared to a previous study basedon simulations of 19 occipital head impacts from the same data source.
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| 3. |
- Antona, Jacobo, 1981, et al.
(författare)
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Development of a comprehensive injury criterion for moderate and mild traumatic brain injuries
- 2016
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Ingår i: International Journal of Automotive Engineering. - : Society of Automotive Engineers of Japan, Inc.. - 2185-0992 .- 2185-0984. ; 7:2, s. 69-75
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injuries are commonly caused by blows that produce sudden accelerations of the head. A methodology to define a new global brain injury criterion and thresholds that account for time-dependent and combined translational-rotational kinematics of the head is described in this paper. In total 43 head impact tests with monkeys conducted in the past were reproduced, using a finite element model of the monkey head and neck. The study found that the new criterion predicted concussions and brain tissue strains more precisely than past criteria. A scheme that scales the proposed injury threshold to be applicable for humans is proposed. The new criterion and threshold may then be used in the design of superior protective systems.
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| 4. |
- Antona, Jacobo, 1981, et al.
(författare)
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Effect of Aging on Brain Injury Prediction in Rotational Head Trauma - A Parameter Study with a Rat Finite Element Model
- 2015
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 16, s. S91-S99
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Tidskriftsartikel (refereegranskat)abstract
- Objective: The aim of this study was to investigate the possible effects of age-related intracranial changes on the potential outcome of diffuse axonal injuries and acute subdural hematoma under rotational head loading.Methods: A simulation-based parametric study was conducted using an updated and validated finite element model of a rat head. The validation included a comparison of predicted brain cortex sliding with respect to the skull. Further, model material properties were modified to account for aging; predicted tissue strains were compared with experimental data in which groups of rats in 2 different lifecycle stages, young adult and mature adult, were subjected to rotational trauma. For the parameter study, 2 age-dependent factors-brain volume and region-specific brain material properties-were implemented into the model. The models young adult and old age were subjected to several injurious and subinjurious sagittal plane rotational acceleration levels. Results: Sequential analysis of the simulated trauma progression indicates that an increase in acute subdural hematoma injury risk indicator occurs at an early stage of the trauma, whereas an increase in diffuse axonal injury risk indicators occurs at a later stage. Tissue stiffening from young adult to mature adult rats produced an increase in strain-based thresholds accompanied by a wider spread of strain distribution toward the rear part of the brain, consistent with rotational trauma experiments with young adult and mature adult rats. Young adult to old age brain tissue softening and brain atrophy resulted in an increase in diffuse axonal injuries and acute subdural hematoma injury risk indicators, respectively. Conclusions: The findings presented in this study suggest that age-specific injury thresholds should be developed to enable the development of superior restraint systems for the elderly. The findings also motivate other further studies on age-dependency of head trauma.
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| 5. |
- Antona, Jacobo, 1981, et al.
(författare)
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Rat brain kinematics and tissue strains associated to Diffuse Axonal Injuries induced by head rotational acceleration
- 2013
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Ingår i: Proceedings of Computational Engineering Conference JSCES. ; 18
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- An anatomically detailed finite element model of a rat head-neck complex has been developed from medical images. The model incorporates material properties from tissue indentation test data captured in the coronal plane from seven brain regions to account for non-homogeneity. The local brain-skull relative displacement has been validated against local brain-slip experimental data in which a thin pin was entered the cortex and rigidly attached to the skull prior to impact. The model is being used to improve the understanding of brain rotational kinematics and to develop brain tissue injury thresholds for Diffuse Axonal Injuries as detected through immuno-histology.
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| 6. |
- Antona, Jacobo, 1981, et al.
(författare)
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Reanalysis of Monkey Head Concussion Experiment Data Using a Novel Monkey Finite Element Model to Develop Brain Tissue Injury Reference Values
- 2012
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Ingår i: Proceeding of the 2012 International IRCOBI Conference on the Biomechanics of Impact. - 2235-3151. ; 2012, s. 441-454
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Konferensbidrag (refereegranskat)abstract
- A new method has been applied to develop a Finite Element (FE) model of the head‐ neck complexof Macaque monkey from medical images. The skull, brain and flesh have been validated based on tissue andcomponent experimental data from literature. The kinematics of the head during occipital impacts have beenvalidated against a sub‐set of head impact experiments carried out in the past at the Japan AutomobileResearch Institute (JARI). The validated model has been used to simulate 19 occipital impacts case‐by‐case. Thecorrelation between obtained peak values for a number of mechanical parameters of the different brain regionsand the occurrence of concussion in the experiments was analysed. Maximum principal strain in the brainstemshowed significant correlation to concussion; 21% strain was associated with a probability of 50% risk forconcussion. The developed model and the presented results constitute the first step towards the developmentof a tissue level injury criterion for humans that is based on experimental animal data.
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| 7. |
- Antona, Jacobo, 1981
(författare)
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Reanalysis of primate head impact experiments to clarify mild traumatic brain injury kinematics and thresholds
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Fatalities and severe injuries due to road traffic accidents still represent a serious health and economic issue intoday’s society. Brain injuries are the most common severe injuries and these injuries account for more than half ofthe 1.3 million traffic related deaths annually worldwide. However, improved accident avoidance systems arepredicted to mitigate and reduce future accident severity. Thus, the number of traffic related deaths and severeinjuries would be reduced and therefore a focus shift towards long-term disabling injuries is expected. One of themost common of such injuries is mild traumatic brain injury.To develop effective countermeasures aimed at reducing traumatic brain injuries, it is essential to understandhead-neck and brain kinematics at impacts to be taken into account in the development of injury criteria and theestablishment of thresholds. With this purpose, experiments comprising animals, used as human surrogates, aredeemed essential and historically, head impact experiments on non-human primates have been carried out. Some ofthese experimental results have been scaled to suit humans and were used in the development of the head injurycriterion, currently in use in the FMVSS 208 US regulation for motor vehicles.This head injury criterion has been used for decades, but is still criticised for not considering many factors thatare important to brain injury. Such factors include the impact direction and area of contact, stiffness of theimpacting surface, and rotational accelerations induced by oblique impacts or when the torso is restrained.Therefore, alternative or complementary criteria that consider rotational acceleration of the head have beenproposed in combination with brain tissue injury criteria, for human head finite element models. The finite elementmodels are currently undergoing validation with reconstructions of real-life sports and traffic accidents, as well asscaled animal injury data. Unfortunately, the accuracy of the methods used to capture head kinematics and detailedbrain injury location and severity from real-life events has limitations. The existing criteria also fail to capture thehead-neck kinematics that causes the brain injuries. Moreover, the methods used to scale animal data to humansare not reliable.The ultimate goal of this study is to generate knowledge that contributes to the development of MTBI criteriaand associated limits that will, when properly applied, reduce the number of moderate brain injuries due to closedhead impacts. This thesis aims at proposing improved criteria that account for the head-neck and brain kinematicsthat occur during brain trauma and to provide thresholds for concussions. This will be facilitated by numericalreconstruction of past head trauma experiments using primates.By re-analysing the existing primate trauma experiments, using a finite element model of these specimens, thereliability of global head injury criteria available in literature was evaluated. This was done by simulating andanalysing sub-sets of frontal and occipital primate head impacts; selected from large series of trauma experimentspreviously conducted at the Japan Automobile Research Institute. Based on the simulation results, the brain injurykinematics hypothesised when the former experiments were analysed is supported: concussions occur due tophysical stress to the brainstem. Based on these findings, brain tissue injury thresholds were also proposed.Assuming that tissue thresholds are the same for non-human primates and humans, these results can be used tointerpret results obtained with human finite element models without scaling.In the future, these results are expected to be used as references for virtual safety assessment and to provide the basis for further development of protective strategies for humans.
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| 8. |
- Antona, Jacobo, 1981
(författare)
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Traumatic Brain Injuries: Animal Experiments and Numerical Simulations to Support the Development of a Brain Injury Criterion
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Traumatic Brain Injuries (TBIs) account for about half of the 1 300 000 annual traffic related deaths and the 50 000 000 injuries worldwide. The burden of TBI is ethically unacceptable and economically unsustainable. Recognising the efforts and achievements in reducing TBI conducted by the vehicle industry, research institutions and academy worldwide, the problem still call for additional research that lead to prevention of TBI. The main aim of this thesis is to develop a brain injury criterion and associated injury thresholds that can be used with crash test dummies in the design of safer cars.The craniocervical motion that produces diffuse brain injuries in experimental settings with animals was investigated by introducing finite element (FE) models of the animals. One rat and one monkey brain FE model were developed from medical images of the animals and validated using experimental data. The validated rat model was applied to simulate sagittal head rotational acceleration experiments with rats. Sequential analysis of the trauma progression indicated that acute subdural haematoma occurred at an early stage of the trauma, while diffuse axonal injury likely occurred at a later stage. The validated monkey model was applied to simulate past head impact experiments with primates that typically produced concussion symptoms. The analysis revealed large brainstem strains supporting the hypothesis that concussions are produced due to mechanical loading of the brainstem. These results also indicate the need to incorporate the craniocervical motion in human FE models and physical test devices in the development of countermeasures for concussive injury prevention.A method to make primate brain injury experimental data applicable for humans was also investigated. The monkey FE model was used to simulate 43 primate head impact experiments. Brain tissue injury risk curves that relate probability of injury, obtained in the experiments, with brain strains estimated in the simulations were developed. By assuming comparable mechanical properties of the brain tissues in monkeys and humans, these risk curves were applied to estimate injury risk in 76 impacts simulated with a human head-neck FE model which was also developed and validated for the purpose of this investigation. Overall, the investigated method proved to be technically feasible and to provide biomechanically justifiable means to related craniocervical kinematics and brain strains. This method accounts for contact phenomena typical from vehicle crash like head impacts, which past scaling techniques did not.Finally, new conceptual global brain injury criterion and injury risk functions that have the potential to predict the risk of diffuse brain injuries, were developed. The concept, denoted as Brain Injury Threshold Surface (BITS), establishes equal brain injury risk surfaces as a function of time-dependent and combined translational and rotational head kinematics typical in head impacts in car crashes. BITS appeared to explain the variance seen in both concussion from the monkey experiments and brain strains levels from the simulations with the monkey and the human brain FE models. Although evaluations of the new criteria and associated risk surfaces are pending, these have the potential to guide the development of superior restraints which would reduce the number and severity of brain injuries in future traffic accidents.
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| 9. |
- Antona, Jacobo, 1981, et al.
(författare)
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Traumatic Brain Injuries in Motor Vehicles Crashes
- 2017
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Ingår i: JSAE Annual Congress, Yokohama, Japan, May 24 to 26, 2017. ; 20175258
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- This study estimates, by means of an analysis of accident data from the US, the incidence and risk of car crash related traumatic brain injuries for occupants in Japanese brand cars. The study incorporated crash type, crash severity, belt use and the victim's age and sex. Concussion risk was the highest among all traumatic brain injuries categories for all crash types and severities; females were at higher risks than males. When concussions were excluded, Subdural Haemorrhages, Intracranial Haemorrhages and Sub-Arachnoid Haemorrhages comprised the most frequent injury categories. Elderly occupants were at considerably higher risks than non-elderly for these bleeding injuries.
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| 10. |
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| 11. |
- Antona, Jacobo, 1981, et al.
(författare)
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Validation of local brain kinematics of a novel rat brain finite element model under rotational acceleration and its application towards the clarification of Diffuse Axonal Injury mechanisms
- 2013
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Ingår i: Proceeding of JSAE Annual Congress, Yokohama, Japan.
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Relative brain-skull displacement under head rotational acceleration in rats was evaluated experimentally. For this, a thin pin was entered the cortex and rigidly attached to the skull prior to impact. For peak rotational accelerations of 1.7 Mrad/s2, the pin scarred the brain cortex; 1.2 mm superficially and less centrally. These measurements were used to validate the brain kinematics of a new anatomically detailed FE model of the head-neck complex of a rat. This model is intended to be used to clarify brain loading mechanisms and to develop brain tissue injury threshold for Diffuse Axonal Injuries as detected through immune-histology.
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| 12. |
- Davidsson, Johan, 1967, et al.
(författare)
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Experiments and Mathematical Modeling for Evaluation of Non-Lethal Weapons
- 2015
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Ingår i: 8th European Symposium on Non-lethal Weapons, May 18-20, Ettlingen, Germany. ; , s. V21-
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The biomechanical response of new and existing non-lethal weapons (NLWs) are to be determined to assess their effectiveness and safety, i.e. the type of injury produced and the risk of such injuries, for the target population and bystanders. The effect and risk of injury varies widely for most NLWs (from no effect to lethality) depending on how the weapon is used, the body region hit and variability in biomechanical response between humans. Commonly the effectiveness and safety provided by a particular NLW are assessed using real-life data from situations in which the NLW have been employed. However, for new NLWs it is necessary to conduct experimental studies using modelsof the human such as anthropometric tests devises (ATDs) and Human Body Models (HBM), post mortem human subjects (PMHSs), animals and cell cultures.While the assessment of possible NLW related injuries in ATDs and PMHSs are crude, animals and cell cultures are excellent for studies of injury mechanisms and injury criteria. For some injuries these mechanisms and criteria can be scaled to humans. The obtained data can also be used in the development of injury risk functions for humans but commonly require scaling. Several of the scaling techniques used in the past are crude. Computer simulation with finite element technique can be used to improve the understanding of experimental studies and to construct injury risk functions at tissue level using data from animal or cell culture experiments. The tissue risk functions can then be used in finite element models of humans to support the development of global injury criteria; to enable theevaluation of new NLWs using ATDs. In this paper we will describe animal models used to study mild and moderate brain injuries and associated finite element models. The paper aims at illustrating the benefit of combining models in biomechanics research and proving guidelines for such studies.
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| 13. |
- Sato Sakayachi, Fusako, 1979, et al.
(författare)
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Investigation of Whole Spine Alignment Patterns in Automotive Seated Posture Using Upright Open MRI Systems
- 2016
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Ingår i: 2016 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury. ; , s. 113-130
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Konferensbidrag (refereegranskat)abstract
- The purpose of this study is to investigate whole spinal alignment patterns in an automotive seated posture. Image data sets of eight female and seven male seated volunteers were acquired using upright open Magnetic Resonance Imaging systems. The images were processed to extract the whole spine alignment defined with the centres of the vertebral bodies. Patterns of the whole spine alignment were investigated through Multi‐Dimensional Scaling analyses. The analysis revealed that variations in the whole spine alignment due to individual differences were seen most remarkably in the combination of curvature of the cervical spinal alignment and degree of the thoracic kyphosis with its peak vertebra level. Subjects with cervical lordosis tended to have a pronounced thoracic kyphosis, with the peak of this kyphosis located at a lower vertebra level. Subjects with cervical kyphosis tended to have a less pronounced thoracic kyphosis, with the peak of this kyphosis at a higher vertebra level. These trends were also observed in the differences of average spinal alignments between males and females.
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