Human Head Injury Research Articles

Head and neck injury risk resulting from impact with small unmanned aerial vehicles: effect of impact speed, angle, and location

It is necessary to analyse the injury risk caused by UAV to establish management standards. A lightweight quadrotor UAV was used to assess the risk of human head and neck injury, taking the impact speed, UAV position, and impact angle into account. First, the MAVIC2 UAV- Hybrid III dummy impacting FE model was developed and verified against the UAV impact tests. Second, lots of simulations were conducted under different impact scenarios to analyse the head and neck injury. Under vertical impact condition, HIC and Nij grew exponentially as the impact speed increased. While under the horizontal impact condition, HIC increased in the form of the power function and Nij increased exponentially. Under vertical impact condition at 20 m/s (maximum flight speed, corresponding to the impact energy of 181.4 J), the HIC was 54% of the threshold, while the Nij was 88% of the threshold, which illustrated that the injury risk of the neck was high, while that of the head was low. Under horizontal impact condition at 20 m/s (181.4 J), the HIC was 51% of the threshold, and the Nij was 24% of the threshold, which illustrated that the injury risk of both the head and neck was low. HIC declined exponentially as the impact angle increased, whereas Nij increased in the form of the power function. Among all the impact positions, the UAV’s arm caused the least injury risk, while the transverse falling attitude between the two arms and the reverse vertical falling attitude generated higher injury risks.

Investigation on the Modeling and Reconstruction of Head Injury Accident Using ABAQUS/Explicit.

A process of modeling and reconstructing human head injuries involved in traffic crashes based on ABAQUS/Explicit is presented in this paper. A high-fidelity finite element (FE) model previously developed by the authors is employed to simulate a real accident case that led to head injury. The most probable head impact position informed by CT images is used for the FE modeling and simulation since the head impact position is critical for accident reconstruction and future analysis of accidents that involve human head injuries. Critical von Mises stress on the skull surface of the head model is chosen as the evaluation criterion for the head injury and FE simulations on 60 cases with various human head-concrete ground impact conditions (impact speeds and angles) were run to obtain those stress values. The FE simulation results are compared with the CT images to determine the minimum speed that will cause skull fracture and the corresponding contact angle at that speed. Our study shows that the minimum speed that would cause skull fracture is 3.5 m/s when the contact angle between the occipital position of the injured head and the ground is about 30°. Effects of the impact speed and the contact angle on the maximum von Mises stress of the head model are revealed from the simulations. The method presented in this paper will help forensic pathologists to examine the head impact injuries and find out the real reasons that lead to those injuries.

A Research on Accident Reconstruction of Bus-Two-Wheeled Vehicle Based on Vehicle Damage and Human Head Injury.

The problem of large calculation models in bus-two-wheeled vehicle traffic accidents (TA) leads to the difficulty of balancing the calculation efficiency and accuracy, as well as difficulties in accident reconstruction. Herein, two typical accidents were reconstructed, based on the rigid-flexible coupled human model (HM) and the Facet vehicle model, and the vehicle damage conditions and the human head biomechanical injury were analyzed. The simulation results showed that the physical process of the human-vehicle collision was basically consistent with the accident video, the windshield fracture was consistent with the actual vehicle report, and the human biomechanical injury characteristics were also consistent with the autopsy report, which verified the feasibility of the simulation model, and provides a basis and reference for forensic identification and for traffic police to deal with accident disputes.

Six-month buprenorphine-naloxone treatment is associated with neurocognitive function improvement in opioid dependence.

Background and Aim:The number of longitudinal studies on cognitive functions in patients on buprenorphine-based agonist treatment is limited. Our objective was to assess the change in neurocognitive functions over the first 6 months of buprenorphine-naloxone (BNX) treatment for opioid dependence (OD) and compare cognitive functions on BNX and controls.Methods:We selected 60 patients with OD aged 18 to 55 years and 20 sex-matched controls; and excluded patients with other substance dependence, human immunodeficiency virus (HIV), head injury, epilepsy, and severe mental illness. We assessed patients thrice: at baseline, 3, and 6 months and Controls once. Cognitive tests included Wisconsin card sorting test (WCST), Iowa gambling task (IGT), trail making tests A and B (TMT-A and B), verbal and visual N-back test (NBT), and standard progressive matrices (SPM). We measured with-in group effect size with Cohen’s D (d).Results:A total of 24 participants completed at least one follow-up; 17 completed both follow-up assessments. All participants were men. At baseline, the patients performed worse than healthy controls in IGT, TMT-A, and B, and visual and verbal NBT. At 3 months, the performance of visual NBT improved significantly (d = 1.2 for NBT1; 1.3 for NBT2). At 6 months, additional performance improvements were seen in WCST (“perseverative error” d = 1.2), IGT (“net total score” d = 1.2), TMT-A (d = 1.1), and verbal NBT (“omission error” d = 1.7). Except for visual-NBT, results did not differ between patients and controls at both follow-ups.Conclusion:Cognitive flexibility, decision making, attention, working memory, and psychomotor speed showed improvements over 6 months of a stable dose of BNX.

Therapeutic Effects of Time-Limited Treatment with Brivaracetam on Posttraumatic Epilepsy after Fluid Percussion Injury in the Rat.

Mounting evidence suggests the synaptic vesicle glycoprotein 2A (SV2A) targeted by levetiracetam may contribute to epileptogenesis. Levetiracetam has shown anti-inflammatory, antioxidant, neuroprotective, and possible antiepileptogenic effects in brain injury and seizure/epilepsy models, and a phase 2 study has signaled a possible clinical antiepileptogenic effect. Brivaracetam shows greater affinity and specificity for SV2A than levetiracetam and broader preclinical antiseizure effects. Thus, we assessed the antiepileptogenic/disease-modifying potential of brivaracetam in an etiologically realistic rat posttraumatic epilepsy model optimized for efficient drug testing. Brivaracetam delivery protocols were designed to maintain clinical moderate-to-high plasma levels in young (5-week-old) male Sprague-Dawley rats for 4 weeks. Treatment protocols were rapidly screened in 4-week experiments using small groups of animals to ensure against rigorous testing of futile treatment protocols. The antiepileptogenic effects of brivaracetam treatment initiated 30 minutes, 4 hours, and 8 hours after rostral parasagittal fluid percussion injury (rpFPI) were then compared with vehicle-treated controls in a fully powered blind and randomized 16-week validation. Seizures were evaluated by video-electrocorticography using a 5-electrode epidural montage. Endpoint measures included incidence, frequency, duration, and spread of seizures. Group sizes and recording durations were supported by published power analyses. Three months after treatment ended, rats treated with brivaracetam starting at 4 hours post-FPI (the best-performing protocol) experienced a 38% decrease in overall incidence of seizures, 59% decrease in seizure frequency, 67% decrease in time spent seizing, and a 45% decrease in the proportion of spreading seizures that was independent of duration-based seizure definition. Thus, brivaracetam shows both antiepileptogenic and disease-modifying properties after rpFPI. SIGNIFICANCE STATEMENT: The rpFPI model, which likely incorporates epileptogenic mechanisms operating after human head injury, can be used to efficiently screen investigational treatment protocols and assess antiepileptogenic/disease-modifying effects. Our studies 1) support a role for SV2A in epileptogenesis, 2) suggest that brivaracetam and other drugs targeting SV2A should be considered for human clinical trials of prevention of post-traumatic epilepsy after head injury, and 3) provide data to inform the design of treatment protocols for clinical trials.

Mechanical Properties of the Cranial Meninges: A Systematic Review.

The meninges are membranous tissues that are pivotal in maintaining homeostasis of the central nervous system. Despite the importance of the cranial meninges in nervous system physiology and in head injury mechanics, our knowledge of the tissues' mechanical behavior and structural composition is limited. This systematic review analyzes the existing literature on the mechanical properties of the meningeal tissues. Publications were identified from a search of Scopus, Academic Search Complete, and Web of Science and screened for eligibility according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The review details the wide range of testing techniques employed to date and the significant variability in the observed experimental findings. Our findings identify many gaps in the current literature that can serve as a guide for future work for meningeal mechanics investigators. The review identifies no peer-reviewed mechanical data on the falx and tentorium tissues, both of which have been identified as key structures in influencing brain injury mechanics. A dearth of mechanical data for the pia-arachnoid complex also was identified (no experimental mechanics studies on the human pia-arachnoid complex were identified), which is desirable for biofidelic modeling of human head injuries. Finally, this review provides recommendations on how experiments can be conducted to allow for standardization of test methodologies, enabling simplified comparisons and conclusions on meningeal mechanics.

An experimental study on advanced lane changing signal assist technology with smart helmet

Nowadays accidents are an increasing concern all over the world. In present scenario accidents are happening due to the factors of improper implementation and usage of helmets while driving Un-Prediction of other vehicle motions, utilizing of low quality helmets. All this carelessness and irresponsible activities plays a dominant role in accidents that are leading to cause of death and disability. Helmets plays a major role for protecting a human head injury in case of accidents. The purpose of this research is to create a smart and secure electronic helmet that plays a vital role in protecting human lives from accidents and this helmet help to send and monitor the information about the vehicle and also the person driving the vehicle. This research mainly focuses on giving indication of alerts to the driver about the surrounding vehicle movements while “changing the lane” and also helps to navigate the driver in correct way for travelling. The effect of a high-speed motorcyclist without wearing a helmet is highly dangerous and can lead to a fatality. Wearing a helmet can reduce damage and save a life. This project is specifically designed to improve the safety of motorcycle riders. Motorcyclists will be alerted if their speed limits are crossed and vehicles that enter the vehicle nearby hit. The helmet system emerging message using cloud-based service will send message to receiving contents in which the database has been stored. There are many countries enforcing a regulations requiring that the motorcycle driver wears a helmet while riding on his motorcycle. Most accidents are caused by reckless driving, drunk or mobile phone use, while traffic laws and rules are violated. Many People lose their lives due to late notification of accident due to that the people are not able to monitor the accident area's precise GPS coordinates. The significant reason that people get injured in head due to not wearing helmet while driving the bike. For the tracking of the rider's head and the acceleration of motorcycle, a Force Sensing resistor (FSR) are used. The motorcycle engine will only be started when the driver buckled the helmet. A LED will flash in helmet while some obstacles or a critical risk. Thus this research helps the researches for implementing and adopting the helmets in various aspects of security and protection of humans in future studies.

Sustained neuronal and microglial alterations are associated with diverse neurobehavioral dysfunction long after experimental brain injury

Traumatic brain injury (TBI) can cause progressive neurodegeneration, sustained neuroinflammation and chronic neurological dysfunction. Few experimental studies have explored the long-term neurobehavioral and functional cellular changes beyond several months. The present study examined the effects of a single moderate-level TBI on functional outcome 8 months after injury. Male C57BL/6 mice were subjected to controlled cortical impact injury and followed for changes in motor performance, learning and memory, as well as depressive-like and social behavior. We also used a novel flow cytometry approach to assess cellular functions in freshly isolated neurons and microglia from the injured tissue. There were marked and diverse, sustained neurobehavioral changes in injured mice. Compared to sham controls, chronic TBI mice showed long-term deficits in gait dynamics, nest building, spatial working memory and recognition memory. The tail suspension, forced swim, and sucrose consumption tests showed a marked depressive-like phenotype that was associated with impaired sociability. At the cellular level, there were lower numbers of Thy1+Tuj1+ neurons and higher numbers of activated CD45loCD11b+ microglia. Functionally, both neurons and microglia exhibited significantly higher levels of oxidative stress after injury. Microglia exhibited chronic deficits in phagocytosis of E. coli bacteria, and increased uptake of myelin and dying neurons. Living neurons showed decreased expression of synaptophysin and postsynaptic density (PSD)-95, along with greater numbers of microtubule-associated protein light chain 3 (LC3)-positive autophagosomes and increased mitochondrial mass that suggest dysregulation of autophagy. In summary, the late neurobehavioral changes found after murine TBI are similar to those found chronically after moderate-severe human head injury. Importantly, such changes are associated with microglial dysfunction and changes in neuronal activity.

Mesh Convergence Behavior and the Effect of Element Integration of a HumanHead Injury Model.

Numerous head injury models exist that vary in mesh density by orders of magnitude. A careful study of the mesh convergence behavior is necessary, especially in terms of strain most relevant to brain injury. To this end, as well as to investigate the effect of element integration scheme on simulated strains, we re-meshed the Worcester Head Injury Model at five mesh densities (~ 7.2-1000k high-quality hexahedral elements of the brain). Results from explicit dynamic simulations of three cadaveric impacts and an in vivo head rotation were compared. First, scalar metrics of the whole brain only considering magnitude were used, including peak maximum principal strain and population-based median strain. They were further extended to deep white matter regions and the entire brain elements, respectively, to form two "response vectors" to account for both magnitude and distribution. Using benchmark enhanced full-integration elements (C3D8I), a minimum of 202.8k brain elements werenecessary to converge for response vectors of the deep white matterregions. This model was further used to simulate with reduced integration (C3D8R). We found that hourglass energy higher than the commonrule of thumb (e.g., up to 44.38% vs. < 10% of internal energy) was necessary to maintain comparable strain relative to C3D8I. Based on these results, it is recommended that a humanhead injury model should have a minimum number of 202.8 k elements, oran average element size of no larger than 1.8mm, for the brain. C3D8R formulation with relax stiffness hourglass control using a high scaling factor is also recommended to achieve sufficient accuracy without substantial computational cost.

A Systematic Review of the Usefulness of Glial Fibrillary Acidic Protein for Predicting Acute Intracranial Lesions following Head Trauma.

The extensive use of computed tomography (CT) after acute head injury is costly and carries potential iatrogenic risk. This systematic review examined the usefulness of blood-based glial fibrillary acidic protein (GFAP) for predicting acute trauma-related CT-positive intracranial lesions following head trauma. The main objective was to summarize the current evidence on blood-based GFAP as a potential screening test for acute CT-positive intracranial lesions following head trauma. We screened MEDLINE, EMBASE, PsychInfo, CINAHL, Web of Science, the Cochrane Database, Scopus, Clinical Trials, OpenGrey, ResearchGate, and the reference lists of eligible publications for original contributions published between January 1980 and January 2017. Eligibility criteria included: (i) population: human head and brain injuries of all severities and ages; (ii) intervention: blood-based GFAP measurement ≤24 h post-injury; and (iii) outcome: acute traumatic lesion on non-contrast head CT ≤24 h post-injury. Three authors completed the publication screening, data extraction, and quality assessment of eligible articles. The initial search identified 4,706 articles, with 51 eligible for subsequent full-text assessment. Twenty-seven articles were ultimately included. Twenty-four (89%) studies reported a positive association between GFAP level and acute trauma-related intracranial lesions on head CT. The area under the receiver operating characteristic curve for GFAP prediction of intracranial pathology ranged from 0.74 to 0.98 indicating good to excellent discrimination. GFAP seemed to discriminate mass lesions and diffuse injury, with mass lesions having significantly higher GFAP levels. There was considerable variability between the measured GFAP averages between studies and assays. No well-designed diagnostic studies with specific GFAP cutoff values predictive of acute traumatic intracranial lesions have been published. Intracranial CT-positive trauma lesions were associated with elevated GFAP levels in the majority of studies. Methodological heterogeneity in GFAP assessments and the lack of well-designed diagnostic studies with commercially validated GFAP platforms hinder the level of evidence, and variability in levels of GFAP with no clearly established cutoff for abnormality limit the clinical usefulness of the biomarker. However, blood-based GFAP holds promise as a means of screening for acute traumatic CT-positive lesion following head trauma.

Development and Validation of Newborn Child Head Numerical Model Dummy for Impact Simulations

Computer simulation using Finite Element Model (FEM) are often used as a substitute for human experimental head injury studies, especially in predicting car accident injuries, enhance understanding of injury mechanism and develop prevention strategies. The use of FEM in crash test dummies is advantageous over physical dummies because of the lower cost and repeatability. Numerous adult FEM of the head have been developed, but there are relatively few paediatric FEM due to scarcity of material property data for children. Consequently, there are not enough models representing newborn child. Child head injury is a costly problem, both in terms of morbidity and direct medical costs. In fact, it is the leading cause of death and disability for children under the age 18-years-old. Despite its importance and effect on the population, the study of paediatric head injury is obstructed by the lack of available paediatric Post-Mortem Human Specimen (PMHS) data. As a substitute for PMHS testing, Anthropometric Test Devices (ATDs) and FEM have been developed to model the head. However, there is a scarcity of data for the design and validation of these models. This paper presents the development and validation of a newborn (NB) FEM for head dummy and simulated results compared with the child cadaver experimental data under drop test conditions. Itis intended for automotive crashworthiness assessment. The model was developed by using both deformable and rigid body materials. The newborn head anthropometric data were obtained from published journal articles. Using recent published material property data, the infant skull, skin and scalp FEM of the newborn ATD head was developed to study the response in head drop tests. The head assembly was validated by using three different head drop tests set-ups. The three impact locations are one frontal/forehead, and two lateral (right and left parietal) drop tests. All tests with drop height of 130 mm are the certification procedure. The benchmark model used in this study was a modified version of the 6-year-old numerical model developed by Livermore Software Technology Corporation and National Crash Analysis Center. A morphing method within LS-Prepost software was used.

1G31 限られた情報での頭部外傷症例解析における神経損傷予測のための再現シミュレーション

Traumatic Brain injury (TBI) is one of the most common causes of death or disability and remains an important public health issue. Diffuse Axonal Injury (DAI) is one of the most frequent closed head injuries. This paper presents a reconstruction simulation and evaluation method for prediction of nerve damage by using computational modeling to simulate a realistic falling accident scenario. The motion of the injured people was reconstructed by MADYMO and kinetic data and hit part were generated. In this case the stress of the brain tissue were calculated in detail by the FE human head model and injury risk was predicted.

Measurement of Force Impact Taekwondo Athletes, Assessing the Possibility of Injury of Human Head

The article presents the results of measurements impact taekwondo athletes to the board which opens after hitting stroke. Measured values are compared with the results of scientific studies that dealt with human head injuries due to the impacts of various kinds. Most often, these results were determined using cadavers bodies. Force action of the athletes on board was realized by direct punches which are combat sport led to facial parts of opponent. In their own measurement was determined time course of forces impinging on the dynamometer plate including size and direction of the force. Dynamometer measured forces to 10000 N. The frequency was set to 1000Hz. Estimate of accuracy was 0.5% of measured value. A composite plate was attached to a dynamometer using special steel structures. When comparing the results was found that the combat sport of taekwondo strikes, including other power effects (eg. others combat sports, falls, blows to the head in accidents, etc.) can cause fractures of the facial bones and even other human head trauma or cervical vertebrae.

Temporal MRI characterization, neurobiochemical and neurobehavioral changes in a mouse repetitive concussive head injury model

Single and repeated sports-related mild traumatic brain injury (mTBI), also referred to as concussion, can result in chronic post-concussive syndrome (PCS), neuropsychological and cognitive deficits, or chronic traumatic encephalopathy (CTE). However PCS is often difficult to diagnose using routine clinical, neuroimaging or laboratory evaluations, while CTE currently only can be definitively diagnosed postmortem. We sought to develop an animal model to simulate human repetitive concussive head injury for systematic study. In this study, mice received single or multiple head impacts by a stereotaxic impact device with a custom-made rubber tip-fitted impactor. Dynamic changes in MRI, neurobiochemical markers (Tau hyperphosphorylation and glia activation in brain tissues) and neurobehavioral functions such as anxiety, depression, motor function and cognitive function at various acute/subacute (1-7 day post-injury) and chronic (14-60 days post-injury) time points were examined. To explore the potential biomarkers of rCHI, serum levels of total Tau (T-Tau) and phosphorylated Tau (P-Tau) were also monitored at various time points. Our results show temporal dynamics of MRI consistent with structural perturbation in the acute phase and neurobiochemical changes (P-Tau and GFAP induction) in the subacute and chronic phase as well as development of chronic neurobehavioral changes, which resemble those observed in mTBI patients.

FINITE ELEMENT ANALYSIS OF THE HUMAN HEAD UNDER SIDE CAR CRASH IMPACTS AT DIFFERENT SPEEDS

Mechanical response of the human head under a side car crash impact is crucial for modeling traumatic brain injuries (TBI) or concussions. The current advances in computational methods and the finite element models of the human head provide a significant opportunity for biomechanical study of brain injuries; however, limited experimental data is available for delineating the injury relationship between the head injury criteria (HIC) and the tensile pressure or von Mises stress. In this research, we assess human head injuries in a side impact car crash using finite element (FE) simulations that quantify the tensile pressures and maximum strain profiles. In doing so, five FE analyses for the human head have been carried out to investigate the correlations between the HIC measured in the dummy model at different moving deformable barrier (MDB) velocities increasing from 10 mph to 30 mph in 5 mph increments and the pressure and von Mises stress of the skull, the skin, the cerebral spinal fluid (CSF) and the brain. The computational simulation results for the tensile pressures and von Mises stresses correlated well with the HIC15 and peak accelerations. Also a second-order polynomial seemed to fit the stress levels to the impact speeds and as such the presented method for using FE human head analysis could be used for reconstruction of head impacts in different side car crash conditions; furthermore, the head model would provide a tool for investigation of the cause and mechanisms of head injuries once the type and locations of injuries are quantified.

Influence of vehicle secondary impact following an emergency braking on an unbelted occupant's neck, head and thorax injuries

Passive safety has for many years reduced the number of fatalities on the roads. However, its effect on occupants’ safety has now stabilised, meaning that new active safety features are needed to reduce further the number of casualties. These active safety features, like autonomous emergency braking (AEB), aim to prevent vehicle collisions and reduce the vehicle kinetic energy on impact. A previous study has shown that unbelted occupants kinematics are affected by the pre-braking phase, suggesting that the occupant's hand positions on the steering wheel, combined with a bracing behaviour, could cause the occupant to miss the deploying airbag in the case of a secondary rigid wall impact. This paper will investigate the variations of the secondary vehicle impact crash patterns by calculating crash pulses based on typical vehicle frontal accident scenarios and conclude on these effects on the human occupant's neck, head and thorax injuries.

The p38α MAPK Regulates Microglial Responsiveness to Diffuse Traumatic Brain Injury

Neuropathology after traumatic brain injury (TBI) is the result of both the immediate impact injury and secondary injury mechanisms. Unresolved post-traumatic glial activation is a secondary injury mechanism that contributes to a chronic state of neuroinflammation in both animal models of TBI and human head injury patients. We recently demonstrated, using in vitro models, that p38α MAPK signaling in microglia is a key event in promoting cytokine production in response to diverse disease-relevant stressors and subsequent inflammatory neuronal dysfunction. From these findings, we hypothesized that the p38α signaling pathway in microglia could be contributing to the secondary neuropathologic sequelae after a diffuse TBI. Mice where microglia were p38α-deficient (p38α KO) were protected against TBI-induced motor deficits and synaptic protein loss. In wild-type (WT) mice, diffuse TBI produced microglia morphological activation that lasted for at least 7 d; however, p38α KO mice failed to activate this response. Unexpectedly, we found that the peak of the early, acute phase cytokine and chemokine levels was increased in injured p38α KO mice compared with injured WT mice. The increased cytokine levels in the p38α KO mice could not be accounted for by more infiltration of macrophages or neutrophils, or increased astrogliosis. By 7 d after injury, the cytokine and chemokine levels remained elevated in injured WT mice but not in p38α KO mice. Together, these data suggest that p38α balances the inflammatory response by acutely attenuating the early proinflammatory cytokine surge while perpetuating the chronic microglia activation after TBI.

The validation and application of a finite element human head model for frontal skull fracture analysis

Traumatic head injuries can result from vehicular accidents, sports, falls or assaults. The current advances in computational methods and the detailed finite element models of the human head provide a significant opportunity for biomechanical study of human head injuries. The biomechanical characteristics of the human head through head impact scenarios can be studied in detail by using the finite element models. Skull fracture is one of the most frequent occurring types of head injuries. The purpose of this study is to analyse the experimental head impacts on cadavers by means of the Strasbourg University Finite Element Head Model (SUFEHM). The results of the numerical model and experimental data are compared for validation purpose. The finite element model has also been applied to predict the skull bone fracture in frontal impacts. The head model includes the scalp, the facial bone, the skull, the cerebral spinal fluid, the meninges, the cerebrum and the cerebellum. The model is used to simulate the experimental frontal head impact tests using a cylindrical padded impactor. Results of the computational simulation shows that the model correlated well with a number of experimental data and a global fracture pattern has been predicted well by the model. Therefore the presented numerical model could be used for reconstruction of head impacts in different impact conditions also the forensic application of the head model would provide a tool for investigation of the causes and mechanism of head injuries.

Why Do Woodpeckers Resist Head Impact Injury: A Biomechanical Investigation

Head injury is a leading cause of morbidity and death in both industrialized and developing countries. It is estimated that brain injuries account for 15% of the burden of fatalities and disabilities, and represent the leading cause of death in young adults. Brain injury may be caused by an impact or a sudden change in the linear and/or angular velocity of the head. However, the woodpecker does not experience any head injury at the high speed of 6–7 m/s with a deceleration of 1000 g when it drums a tree trunk. It is still not known how woodpeckers protect their brain from impact injury. In order to investigate this, two synchronous high-speed video systems were used to observe the pecking process, and the force sensor was used to measure the peck force. The mechanical properties and macro/micro morphological structure in woodpecker's head were investigated using a mechanical testing system and micro-CT scanning. Finite element (FE) models of the woodpecker's head were established to study the dynamic intracranial responses. The result showed that macro/micro morphology of cranial bone and beak can be recognized as a major contributor to non-impact-injuries. This biomechanical analysis makes it possible to visualize events during woodpecker pecking and may inspire new approaches to prevention and treatment of human head injury.

Pathophysiological Response to Experimental Diffuse Brain Trauma Differs as a Function of Developmental Age

The purpose of experimental models of traumatic brain injury (TBI) is to reproduce selected aspects of human head injury such as brain edema, contusion or concussion, and functional deficits, among others. As the immature brain may be particularly vulnerable to injury during critical periods of development, and pediatric TBI may cause neurobehavioral deficits, our aim was to develop and characterize as a function of developmental age a model of diffuse TBI (DTBI) with quantifiable functional deficits. We modified a DTBI rat model initially developed by us in adult animals to study the graded response to injury as a function of developmental age – 7-, 14- and 21-day-old rats compared to young adult (3-month-old) animals. Our model caused motor deficits that persisted even after the pups reached adulthood, as well as reduced cognitive performance 2 weeks after injury. Moreover, our model induced prominent edema often seen in pediatric TBI, particularly evident in 7- and 14-day-old animals, as measured by both the wet weight/dry weight method and diffusion-weighted MRI. Blood-brain barrier permeability, as measured by the Evans blue dye technique, peaked at 20 min after trauma in all age groups, with a second peak found only in adult animals at 24 h after injury. Phosphorus MR spectroscopy showed no significant changes in the brain energy metabolism of immature rats with moderate DTBI, in contrast to significant decreases previously identified in adult animals.