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An examination of American football helmets using brain deformation metrics associated with concussion

2013-03, Post, Andrew, Oeur, Anna, Hoshizaki, Thomas Blaine, et al.

The sport of American football is associated with a high incidence of concussion, which research has identified may lead to long term neurological damage. As a result, it is important that protective technologies be developed to help mitigate the incidence of this type of brain trauma. This research examines how the design characteristics between different American football helmet models affect the linear and rotational acceleration responses as well as brain deformation metrics using a centric/non-centric impacting protocol. The protocol involved impacting the helmets at nine centric/non-centric sites. Brain deformation metrics were calculated using the University College Dublin Brain Trauma Model. The results revealed that design characteristics do influence the brain deformation metrics associated with incidence of concussion. Further analysis revealed that rotational acceleration was more related to brain deformation metrics than linear acceleration. These results show that when attempting to reduce brain deformation metrics, the development of rotational acceleration diminishing technologies may be beneficial. This research indicates that helmet design may be able to reduce the risk of concussive injury.

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The Influence of Impact Angle on the Dynamic Response of a Hybrid III Headform and Brain Tissue Deformation

2014-03-12, Oeur, Anna, Hoshizaki, Thomas Blaine, Gilchrist, M. D.

The objective of this study was to investigate the influence of impact angle on the dynamic response of a Hybrid III headform and brain tissue deformation by impacting the front and side of the headform with four angle conditions (0° at the impact site and 5°, 10° and 15° counter-clockwise rotations from 0°) as well as three additional angles of -5°, -10° and -15° (clockwise rotations from 0°) at the side location to examine the effect of direction. The acceleration-time curves were used as input into a finite element model of the brain where maximum principal strain was calculated. The results from this study show that impact angle has an asymmetrical influence on headform dynamic responses and strain. An increase in impact angle tends to result in a growth of headform linear and rotational acceleration and maximum principal strain for the front location as well as the negative angles (0 to -15°) at the side, however varying trends were observed for the positive angles (from 0° to 15°) at the side. When developing sophisticated impact protocols and undertaking head injury reconstruction research, it is important to be aware of impact angle.

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The influence of impact angle on the dynamic response of a Hybrid III headform and brain tissue deformation

2012, Oeur, Anna, Hoshizaki, Thomas Blaine, Gilchrist, M. D.

The objective of this study was to investigate the influence of impact angle on the dynamic response of a Hybrid III headform and brain tissue deformation by impacting the front and side of the headform using four angle conditions (0°, at the impact site and 5, 10 and 15° rightward rotations of the headform from 0°) as well as three additional angle conditions of -5, - 10 and -15° (leftward rotations from 0°) at the side location to examine the effects of the neckform. The acceleration-time curves were used as input into a finite element model of the brain where maximum principal strain was calculated. The study found that an impact angle of 15° significantly influencesthe results when measured using linear and rotational acceleration and maximum principal strain. When developing sophisticated impact protocols and undertaking head injury reconstruction research, it is important to be aware of impact angle.

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The influence of centric and non-centric impacts to American football helmets on the correlation between commonly metrics in brain injury research

2012, Post, Andrew, Oeur, Anna, Hoshizaki, Thomas Blaine, et al.

Concussion has become recognized as an injury which can be a source of long term neurological damage. This has led to research into which metrics may be more appropriate to define risk of injury. Some researchers support the use of linear acceleration as a metric for concussion, while others suggest the use of linear and rotational acceleration as well as brain deformation metrics. The purpose of this study was to examine the relationships between these metrics using a centric and non‐centric impact protocol. A linear impactor was used to impact a Hybrid III headform fitted with different models of American football helmet using a centric and non‐centric protocol. The dynamic response was then used as input to the FE model for analysis of brain deformations. The results showed that linear acceleration was correlated to rotational acceleration and brain deformation for centric conditions, but under non‐centric conditions it was not. These results indicate that the type of methodology used will influence the relationship between the variables used to assign risk of concussion. These results also support the use of a centric/non‐centric protocol and measurement of rotational acceleration and brain deformation when it comes to the development of helmet technologies.

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Examination of the relationship between peak linear and angular accelerations to brain deformation metrics in hockey helmet impacts

2013-05, Post, Andrew, Oeur, Anna, Hoshizaki, Thomas Blaine, et al.

Ice hockey is a contact sport which has a high incidence of brain injury. The current methods of evaluating protective devices use peak resultant linear acceleration as their pass/fail criteria, which are not fully representative of brain injuries as a whole. The purpose of this study was to examine how the linear and angular acceleration loading curves from a helmeted impact influence currently used brain deformation injury metrics. A helmeted Hybrid III headform was impacted in five centric and non-centric impact sites to elicit linear and angular acceleration responses. These responses were examined through the use of a brain model. The results indicated that when the helmet is examined using peak resultant linear acceleration alone, they are similar and protective, but when a 3D brain deformation response is used to examine the helmets, there are risks of brain injury with lower linear accelerations which would pass standard certifications for safety.