Albert King - Academia.edu (original) (raw)

Papers by Albert King

The Biomechanics of Impact Injury, 2017

In retrospect, the experimental research carried out in head injury had the biomechanical objecti... more In retrospect, the experimental research carried out in head injury had the biomechanical objectives that were outlined in Chap. 1 (Sect. 1.6) although they were not clearly explained until much later. The research began with the work of Gurdjian and associates in the mid-1950s followed by the work of Ommaya and associates. The purpose of their work was to try to understand the mechanisms of brain injury. Suffering from the lack of what we now call modern technology, the researchers used head acceleration and intracranial pressure as possible parameters that might be able to explain how the brain is injured. These were the only measurable parameters available at the time, and they were used to try to explain how brain injury occurs. Out of that research came the two competing theories of brain injury-the linear and angular acceleration mechanisms. Brain motion within the skull during an impact was not measurable for most of the twentieth century. As a result, impact response was limited to the study of skull response to impact. The response data did not add any insight into brain response but did provide important data for the design of a humanlike dummy head-the head of the Hybrid III dummy. Accurate data on brain response became available in 2001. The search for measures that can accurately predict the tolerance of the brain to impact began with the work done at Wayne State University which published the so-called Wayne State Tolerance Curve (WSTC). This led to a couple of injury criteria which are still in use to this day. The history behind the development of these criteria is discussed in this chapter. The evaluation of vehicular safety features utilizes crash dummies and computer models. The research and development of crash dummies are beyond the scope of this book, and models of the brain are discussed in the next chapter.

SAE Technical Paper Series, 2006

Journal of Biomechanical Engineering, 2004

Traumatic brain injuries constitute a significant portion of injury resulting from automotive col... more Traumatic brain injuries constitute a significant portion of injury resulting from automotive collisions, motorcycle crashes, and sports collisions. Brain injuries not only represent a serious trauma for those involved but also place an enormous burden on society, often exacting a heavy economical, social, and emotional price. Development of intervention strategies to prevent or minimize these injuries requires a complete understanding of injury mechanisms, response and tolerance level. In this study, an attempt is made to delineate actual injury causation and establish a meaningful injury criterion through the use of the actual field accident data. Twenty-four head-to-head field collisions that occurred in professional football games were duplicated using a validated finite element human head model. The injury predictors and injury levels were analyzed based on resulting brain tissue responses and were correlated with the site and occurrence of mild traumatic brain injury (MTBI). P...

Journal of Neurosurgery, 2012

Journal of Biomechanics, 2008

SAE Technical Paper Series, 2007

High-speed biplane x-ray and neutral density targets were used to examine brain displacement and ... more High-speed biplane x-ray and neutral density targets were used to examine brain displacement and deformation during impact. Relative motion, maximum principal strain, maximum shear strain, and intracranial pressure were measured in thirty-five impacts using eight human cadaver head and neck specimens. The effect of a helmet was evaluated. During impact, local brain tissue tends to keep its position and shape with respect to the inertial frame, resulting in relative motion between the brain and skull and deformation of the brain. The local brain motions tend to follow looping patterns. Similar patterns are observed for impact in different planes, with some degree of posterior-anterior and right-left symmetry. Peak coup pressure and pressure rate increase with increasing linear acceleration, but coup pressure pulse duration decreases. Peak average maximum principal strain and maximum shear are on the order of 0.09 for CFC 60 Hz data for these tests. Peak average maximum principal strain and maximum shear increase with increasing linear acceleration, coup pressure, and coup pressure rate. Linear and angular acceleration of the head are reduced with use of a helmet, but strain increases. These results can be used for the validation of finite element models of the human head.

PloS one, 2017

With the rapid increase in the number of blast induced traumatic brain injuries and associated ne... more With the rapid increase in the number of blast induced traumatic brain injuries and associated neuropsychological consequences in veterans returning from the operations in Iraq and Afghanistan, the need to better understand the neuropathological sequelae following exposure to an open field blast exposure is still critical. Although a large body of experimental studies have attempted to address these pathological changes using shock tube models of blast injury, studies directed at understanding changes in a gyrencephalic brain exposed to a true open field blast are limited and thus forms the focus of this study. Anesthetized, male Yucatan swine were subjected to forward facing medium blast overpressure (peak side on overpressure 224-332 kPa; n = 7) or high blast overpressure (peak side on overpressure 350-403 kPa; n = 5) by detonating 3.6 kg of composition-4 charge. Sham animals (n = 5) were subjected to all the conditions without blast exposure. After a 3-day survival period, the br...

Frontiers in Neurology, 2016

Blast-induced traumatic brain injury (bTBI) is a signature wound of modern warfare. The current i... more Blast-induced traumatic brain injury (bTBI) is a signature wound of modern warfare. The current incomplete understanding of its injury mechanism impedes the development of strategies for effective protection of bTBI. Despite a considerable amount of experimental animal studies focused on the evaluation of brain neurotrauma caused by blast exposure, there is very limited knowledge on the biomechanical responses of the gyrenecephalic brain subjected to primary free-field blast waves imposed in vivo. This study aims to evaluate the external and internal mechanical responses of the brain against different levels of blast loading with Yucatan swine in free field. The incident overpressure (IOP) was generated using 3.6 kg of C4 charge placed at three standoff distances from the swine. Five swine were exposed to a total of 19 blasts. The three average peak IOP pressure levels in this study were 148.8, 278.9, and 409.2 kPa as measured by a pencil probe. The duration of the first positive wave was in the range of 2.1-3 ms. Pressure changes in the brain and head kinematics were recorded with intracranial pressure (ICP) sensors, linear accelerometers, and angular rate sensors. The corresponding average peak ICPs were in the range of 79-143, 210-281, and 311-414 kPa designated as low, medium, and high blast level, respectively. Peak head linear accelerations were in the range of 120-412 g. A positive correlation between IOP and its corresponding biomechanical responses of the brain was also observed. These experimental data can be used to validate computer models of bTBI.

Journal of biomechanical engineering, 2016

Most studies on football helmet performance focus on lowering head acceleration-related parameter... more Most studies on football helmet performance focus on lowering head acceleration-related parameters to reduce concussions. This has resulted in an increase in helmet size and mass. The objective of this paper was to study the effect of helmet mass on head and upper neck responses. Two independent test series were conducted. In test series one, 90 pendulum impact tests were conducted with four different headform and helmet conditions: unhelmeted Hybrid III headform, Hybrid III headform with a football helmet shell, Hybrid III headform with helmet shell and facemask, and Hybrid III headform with the helmet and facemask with mass added to the shell (n = 90). The Hybrid III neck was used for all the conditions. For all the configurations combined, the shell only, shell and facemask, and weighted helmet conditions resulted in 36%, 43%, and 44% lower resultant head accelerations (p < 0.0001), respectively, when compared to the unhelmeted condition. Head delta-V reductions were 1.1%, 4.5...

Pain Research and Management, 2003

The purpose of this study was to document the kinematics of the neck during low-speed rear-end im... more The purpose of this study was to document the kinematics of the neck during low-speed rear-end impacts. In a series of experiments reported by Deng et al (2000), a pneumatically driven mini-sled was used to study cervical spine motion using six cadavers instrumented with metallic markers at each cervical level, a 9-accelerometer mount on the head, and a tri-axial accelerometers on the thorax. A 250-Hz x-ray system was used to record marker motion while acceleration data were digitized at 10,000 Hz. Results show that, in the global coordinate system, the head and all cervical vertebrae were primarily in extension during the entire period of x-ray data collection. In local coordinate systems, upper cervical segments were initially in relative flexion while lower segments were in extension. Facet joint capsular stretch ranged from 17 to 97%. In the vertical direction, the head and T1 accelerated upward almost instantaneously after impact initiation while there was delay for the head in...

Annual proceedings / Association for the Advancement of Automotive Medicine. Association for the Advancement of Automotive Medicine, 2005

The objective of this study was to investigate the main injury patterns and sources of non-ejecte... more The objective of this study was to investigate the main injury patterns and sources of non-ejected occupants (i.e. no full/partial ejection) during trip-over crashes, using the NASS-CDS database. Specific injury types and sources of the head, chest, and neck were identified. Results from this study suggest that cerebrum injuries, especially subarachnoid hemorrhage, rib fractures, lung injuries, and cervical spine fractures need to be emphasized if cadaveric tests or numerical simulations are designed to study rollover injury mechanisms. The roof has been identified as the major source for head and neck injuries. However, changing the roof design alone is not likely to improve rollover safety. Instead, the belt restraint systems, passive airbags, roof structure, and new innovations need to be considered in a systematic manner to provide enhanced rollover occupant protection.

Annual proceedings / Association for the Advancement of Automotive Medicine. Association for the Advancement of Automotive Medicine, 2007

A weighted logistic regression with careful selection of crash, vehicle, occupant and injury data... more A weighted logistic regression with careful selection of crash, vehicle, occupant and injury data and sequentially adjusting the covariants, was used to investigate the predictors of the odds of head/face and neck (HFN) injuries during rollovers. The results show that unbelted occupants have statistically significant higher HFN injury risks than belted occupants. Age, number of quarter-turns, rollover initiation type, maximum lateral deformation adjacent to the occupant, A-pillar and B-pillar deformation are significant predictors of HFN injury odds for belted occupants. Age, rollover leading side and windshield header deformation are significant predictors of HFN injury odds for unbelted occupants. The results also show that the significant predictors are different between head/face (HF) and neck injury odds, indicating the injury mechanisms of HF and neck injuries are different.

Theoretical Biomechanics, 2011

SAE Technical Paper Series, 1985

Revue des recherches recentes en ce qui concerne les mecanismes de dommages corporels et la toler... more Revue des recherches recentes en ce qui concerne les mecanismes de dommages corporels et la tolerance a ces derniers. Les recherches essaient de resoudre les problemes dans les systemes de securite des automobiles

Traffic Injury Prevention, 2005

The purpose of this study was to determine a mechanism of injury of the forefoot observed in some... more The purpose of this study was to determine a mechanism of injury of the forefoot observed in some frontal offset car crashes. To verify an injury mechanism, research was conducted in an effort to reproduce Lisfranc type injuries in the cadaver. Impact tests conducted at speeds of up to 16 m/s simulated knee-leg-foot entrapment, floor pan intrusions, whole-body deceleration, muscle tension and foot/pedal interaction. Two possible mechanisms of injury were investigated the Plantar Nominal Configuration and the Plantar Flexed Configuration. The configuration of the foot made a difference in the frequency and severity of the injuries. KEYWORDS-Forefoot injuries, Lisfranc type injuries, Metatarsal injuries, Tarsometatarsal injuries, Ligamentous injury.

Journal of Neurotrauma, 2010

The controlled cortical impact (CCI) model has been extensively used to study region-specific pat... more The controlled cortical impact (CCI) model has been extensively used to study region-specific patterns of neuronal injury and cell death after a focal traumatic brain injury. Although external parameters such as impact velocity and depth of penetration have been defined in this injury model, little is known about the intracranial mechanical responses within cortical and subcortical brain regions where neuronal loss is prevalent. At present, one of the best methods to determine the internal responses of the brain is finite element (FE) modeling. A previously developed and biomechanically validated detailed three-dimensional FE rat brain model, consisting of 255,700 hexahedral elements and representing all essential anatomical features of a rat brain, was used to study intracranial responses in a series of CCI experiments in which injury severity ranged from mild to severe. A linear relationship was found between the percentage of the neuronal loss observed in vivo and the FE model-predicted maximum principal strain (R 2 ¼ 0.602). Interestingly, the FE model also predicted some risk of injury in the cerebellum, located remote from the point of impact, with a 25% neuronal loss for the ''severe'' impact condition. More research is needed to examine other regions that do not have histological data for comparison with FE model predictions before this injury mechanism and the associated injury threshold can be fully established.

Journal of Neurosurgery, 2007

Object The aims of this study were to develop a three-dimensional patient-specific finite element... more Object The aims of this study were to develop a three-dimensional patient-specific finite element (FE) brain model with detailed anatomical structures and appropriate material properties to predict intraoperative brain shift during neurosurgery and to update preoperative magnetic resonance (MR) images using FE modeling for presurgical planning. Methods A template-based algorithm was developed to build a 3D patient-specific FE brain model. The template model is a 50th percentile male FE brain model with gray and white matter, ventricles, pia mater, dura mater, falx, tentorium, brainstem, and cerebellum. Gravity-induced brain shift after opening of the dura was simulated based on one clinical case of computer-assisted neurosurgery for model validation. Preoperative MR images were updated using an FE model and displayed as intraoperative MR images easily recognizable by surgeons. To demonstrate the potential of FE modeling in presurgical planning, intraoperative brain shift was predict...

Journal of Neuroscience Methods, 2011

Computer models of the head can be used to simulate the events associated with traumatic brain in... more Computer models of the head can be used to simulate the events associated with traumatic brain injury (TBI) and quantify biomechanical response within the brain. Marmarou's impact acceleration rodent model is a widely used experimental model of TBI mirroring axonal pathology in humans. The mechanical properties of the low density polyurethane (PU) foam, an essential piece of energy management used in Marmarou's impact device, has not been fully characterized. The foam used in Marmarou's device was tested at seven strain rates ranging from quasi-static to dynamic (0.014 ~ 42.86 s −1) to quantify the stress-strain relationships in compression. Recovery rate of the foam after cyclic compression was also determined through the periods of recovery up to three weeks. The experimentally determined stress-strain curves were incorporated into a material model in an explicit Finite Element (FE) solver to validate the strain rate dependency of the FE foam model. Compression test results have shown that the foam used in the rodent impact acceleration model is strain rate dependent. The foam has been found to be reusable for multiple impacts. However the stress resistance of used foam is reduced to 70% of the new foam. The FU_CHANG_FOAM material model in an FE solver has been found to be adequate to simulate this rate sensitive foam.

Journal of Biomechanics, 2013

On-field measurement of head impacts has relied on the Head Impact Telemetry (HIT) System, which ... more On-field measurement of head impacts has relied on the Head Impact Telemetry (HIT) System, which uses helmet mounted accelerometers to determine linear and angular head accelerations. HIT is used in youth and collegiate football to assess the frequency and severity of helmet impacts. This paper evaluates the accuracy of HIT for individual head impacts. Most HIT validations used a medium helmet on a Hybrid III head. However, the appropriate helmet is large based on the Hybrid III head circumference (58 cm) and manufacturer&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;#39;s fitting instructions. An instrumented skull cap was used to measure the pressure between the head of football players (n=63) and their helmet. The average pressure with a large helmet on the Hybrid III was comparable to the average pressure from helmets used by players. A medium helmet on the Hybrid III produced average pressures greater than the 99th percentile volunteer pressure level. Linear impactor tests were conducted using a large and medium helmet on the Hybrid III. Testing was conducted by two independent laboratories. HIT data were compared to data from the Hybrid III equipped with a 3-2-2-2 accelerometer array. The absolute and root mean square error (RMSE) for HIT were computed for each impact (n=90). Fifty-five percent (n=49) had an absolute error greater than 15% while the RMSE was 59.1% for peak linear acceleration.