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News Article | May 1, 2017
Site: www.chromatographytechniques.com

Scientists have modeled what happens to the brain of a football player when he collides forcefully with another player. The study, conducted by researchers at Imperial College London, was carried out to understand in more detail the link between traumatic brain injury (TBI) and chronic traumatic encephalopathy (CTE). The latter is a form of dementia and causes a long-term build-up of proteins called tau, associated with the degeneration of brain tissue and declining health. TBI occurs when an external force impacts on the brain. People who have been involved in one-off TBI incidents such as motorcycle accidents, and sportspeople like footballers who have repetitive TBIs from collisions on the field, are both vulnerable to CTE. Scientists believe there is a link between the initial impact in a TBI and where tau deposits build up in the brain. Now, Imperial researchers have modeled how brain tissue deforms during an impact between two American football players on the field. They have also modeled what happens to a person's brain when they have a ground-level fall and the initial impact to the brain in a motorcycle accident. They compared their 3-D high-fidelity models to MRI data on a cohort of 97 patients with TBI, and studies on post-mortem data of the brains of footballers from America's National Football Association (NFL) with CTE, previously donated to science institutes in America for analysis. They observed tau deposition in the brains, which was then diagnosed as CTE. "In TBI, the force of the blow shakes the brain, which is similar in texture to jelly. This shaking process deforms the brain tissue and can cause ruptured blood vessels and damaged nerve cells, and more severe complications later on. We've been able to replicate those initial moments when the 'jelly' brain is first deformed on impact, by combining engineering principles and medical knowledge. This is providing us with new insights," said Mazdak Ghajari, an engineer who co-led the study from the Dyson School of Design Engineering at Imperial College London. The Imperial team showed in all their 3-D models that the damage created from a TBI is greatest in the depths of the folds on the surface of the brain called sulci. Previous studies on CTE have shown that tau also accumulates in sulci. In addition, the team discovered that the location and severity of the blow to the head on impact can have a significant influence on the magnitude and pattern of the injury later on when CTE develops. The researchers say further clarification of these links in future studies will be the key to analyzing the long-term effects of head impacts. This could lead to new improvements in protective strategies, including new types of helmet designs. "Current technologies for assessing helmet safety are pretty crude. Our work is still in the early stages, but we believe that it shows promise for more accurately modeling how the brain deforms in different types of impacts. Using this knowledge we could refine the design of particular areas of helmets so that they could withstand collisions associated with particular types of sports. We could also design headgear that is more able to shield motorcyclists, who are so vulnerable on the road. Ultimately, we think better protective wear may prevent long-term diseases such as CTE," added Ghajari. The team carried out their modeling by gathering data from real incidents. In the case of the American football players, the Imperial team used data that was originally collected by Biokinetics and Associates Ltd (Canada). The data was collected from NFL games that occurred from 1996 to 2001. A total of 182 collisions were recorded in the study. The Imperial team chose a collision that they thought was reconstructed well in the lab and input this data into their model. The team reconstructed the second injury using medical records that detailed a patient's fall to a marble floor, from ground level. They reconstructed the fall using a dummy and recorded the head accelerations during impact. The accident involving a collision between a motorcyclist and a passenger car was reconstructed at the Transport Research Laboratory. Instruments were fitted inside a dummy head wearing a helmet, identical to the one worn in the accident, and the impacts were recorded. The location and velocity of the impact were adjusted to closely replicate the damage seen on the shell and lining of the helmet. The information recorded from the sensors during each reconstruction was fed into a 3-D model on a computer, created from MRI scans of a healthy 34-year-old male. The team's software enabled them to pixelate the head into one million hexahedral elements and a quarter of a million quadrilateral elements, which represented 11 types of tissues including the scalp, skull, brain and anatomical features such as the sulci. This gave them the high fidelity capacity to focus in detail on parts most damaged from the initial impact of a TBI. They then compared their models with the MRI data and post-mortem studies of American footballers with CTE, which showed mechanical forces at the time of collision are concentrated in locations of tau deposition seen in the footballers' brains with dementia. "We are very excited by the ability to link the early and late effects of head injuries. A large challenge is identifying patients at risk of dementia after head injury and our study provides a way to connect the critical events in this process. We will be working to understand how the way the brain deforms leads to brain degeneration, as this will be key to protecting against dementia," said David Sharp, co-author from the Department of Medicine at Imperial College London. The researchers plan to use the computer model to optimize the design of sporting headgears, with focus on two mainstream sports, American football and horse riding. The team will also be working with researchers from the Royal British Legion Centre for Blast Studies at Imperial, exploring the effects of blasts on brain tissue.


Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Halstead D.,University of Tennessee at Knoxville | Halstead D.,Southern Impact Research Center
Annals of Biomedical Engineering | Year: 2012

Linear impact tests were conducted on 17 modern football helmets. The helmets were placed on the Hybrid III head with the neck attached to a sliding table. The head was instrumented with an array of 3-2-2-2 accelerometers to determine translational acceleration, rotational acceleration, and HIC. Twenty-three (23) different impacts were conducted on four identical helmets of each model at eight sites on the shell and facemask, four speeds (5.5, 7.4, 9.3, and 11.2 m/s) and two temperatures (22.2 and 37.8 °C). There were 1,850 tests in total; 276 established the 1990s helmet performance (baseline) and 1,564 were on the 17 different helmet models. Differences from the 1990s baseline were evaluated using the Student t test (p < 0.05 as significant). Four of the helmets had significantly lower HICs and head accelerations than the 1990s baseline with average reductions of 14.6-21.9% in HIC, 7.3-14.0% in translational acceleration, and 8.4-15.9% in rotational acceleration. Four other helmets showed some improvements. Eight were not statistically different from the 1990s baseline and one had significantly poorer performance. Of the 17 helmet models, four provided a significant reduction in head responses compared to 1990s helmets. © 2011 Biomedical Engineering Society.


Bourget D.,Defense R and D Canada Valcartier | Anctil B.,Biokinetics and Associates Ltd.
2011 IRCOBI Conference Proceedings - International Research Council on the Biomechanics of Injury | Year: 2011

Non-lethal capability sets, which include Kinetic Energy Non Lethal Weapons (KENLW), have been acquired by the Canadian Forces during the last years but their effects on human targets are not fully understood. This paper presents various methods to evaluate their safety aspects with the goal to minimize the occurrence of lethal or serious injuries produced by KENLW. Test methods to assess the blunt impact effects of KENLW on the eyes, face, skull and thorax are discussed.


Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Wonnacott M.,Biokinetics and Associates Ltd.
Annals of Biomedical Engineering | Year: 2012

The potential for mouthguards to change the risk of concussion was studied in football helmet impacts. The Hybrid III head was modified with an articulating mandible, dentition, and compliant temporomandibular joints (TMJ). It was instrumented for triaxial head acceleration and triaxial force at the TMJs and upper dentition. Mandible force and displacement were validated against cadaver impacts to the chin. In phase 1, one of five mouthguards significantly lowered HIC in 6.7 m/s impacts (p = 0.025) from the no mouthguard condition but not in 9.5 m/s tests. In phase 2, eight mouthguards increased HIC from +1 to +17% in facemask impacts that loaded the chinstraps and mandible; one was statistically higher (p = 0.018). Peak head acceleration was +1 to +15% higher with six mouthguards and 2-3% lower with two others. The differences were not statistically significant. Five of eight mouthguards significantly reduced forces on the upper dentition by 40.8-63.9%. Mouthguards tested in this study with the Hybrid III articulating mandible lowered forces on the dentition and TMJ, but generally did not influence HIC or concussion risks. © 2011 Biomedical Engineering Society.


Viano D.C.,ProBiomechanics LLC | Withnall C.,Biokinetics and Associates Ltd. | Wonnacott M.,Biokinetics and Associates Ltd.
Annals of Biomedical Engineering | Year: 2012

An instrumented Hybrid III head was placed in a Schutt ION 4D football helmet and dropped on different turfs to study field types and temperature on head responses. The head was dropped 0.91 and 1.83 m giving impacts of 4.2 and 6.0 m/s on nine different football fields (natural, Astroplay, Fieldturf, or Gameday turfs) at turf temperatures of -2.7 to 23.9 °C. Six repeat tests were conducted for each surface at 0.3 m (1′) intervals. The Hybrid III was instrumented with triaxial accelerometers to determine head responses for the different playing surfaces. For the 0.91-m drops, peak head acceleration varied from 63.3 to 117.1 g and HIC 15 from 195 to 478 with the different playing surfaces. The lowest response was with Astroplay, followed by the engineered natural turf. Gameday and Fieldturf involved higher responses. The differences between surfaces decreased in the 1.83 m tests. The cold weather testing involved higher accelerations, HIC 15 and delta V for each surface. The helmet drop test used in this study provides a simple and convenient means of evaluating the compliance and energy absorption of football playing surfaces. The type and temperature of the playing surface influence head responses. © 2011 Biomedical Engineering Society.


Wonnacott M.,Biokinetics and Associates Ltd. | Withnall C.,Biokinetics and Associates Ltd.
SAE Technical Papers | Year: 2010

Current state of the art in Anthropometric Test Device (ATD) headform development does not include biofidelity of the mandible and the temporomandibular joint (TMJ). In order to investigate the protective aspects of mouth guards in relation to mild traumatic brain injury (mTBI) potential, a headform with an articulating mandible has been developed. The headform is based upon the 50% male Hybrid III and has a steel mandible with steel upper and lower dentition and a compliant TMJ structure. The headform may be instrumented with tri-axial C.G. accelerometers, and includes tri-axial force sensors at both left and right TMJ's as well as the upper dentition. Mandible force and displacement response under direct chin impact has been validated against cadaver corridors developed recently at Wayne State University. The headform was developed under sponsorship of the National Football League primarily to assess the capability of mouth guards to reduce concussion risk in helmeted American football impacts. However this headform may also have application to other fields, such as military and automotive towards mandible, TMJ and dentition injury prevention research. Copyright © 2010 SAE International.

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