scholarly journals Brain injury in sports

2016 ◽  
Vol 124 (3) ◽  
pp. 667-674 ◽  
Author(s):  
John Lloyd ◽  
Frank Conidi
Keyword(s):  
Brain Injuries ◽  
Scientific Evidence ◽  
Head Injuries ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Impact Testing ◽  
Common Belief ◽  
Percentage Reduction ◽  
Football Helmets

OBJECT Helmets are used for sports, military, and transportation to protect against impact forces and associated injuries. The common belief among end users is that the helmet protects the whole head, including the brain. However, current consensus among biomechanists and sports neurologists indicates that helmets do not provide significant protection against concussion and brain injuries. In this paper the authors present existing scientific evidence on the mechanisms underlying traumatic head and brain injuries, along with a biomechanical evaluation of 21 current and retired football helmets. METHODS The National Operating Committee on Standards for Athletic Equipment (NOCSAE) standard test apparatus was modified and validated for impact testing of protective headwear to include the measurement of both linear and angular kinematics. From a drop height of 2.0 m onto a flat steel anvil, each football helmet was impacted 5 times in the occipital area. RESULTS Skull fracture risk was determined for each of the current varsity football helmets by calculating the percentage reduction in linear acceleration relative to a 140-g skull fracture threshold. Risk of subdural hematoma was determined by calculating the percentage reduction in angular acceleration relative to the bridging vein failure threshold, computed as a function of impact duration. Ranking the helmets according to their performance under these criteria, the authors determined that the Schutt Vengeance performed the best overall. CONCLUSIONS The study findings demonstrated that not all football helmets provide equal or adequate protection against either focal head injuries or traumatic brain injuries. In fact, some of the most popular helmets on the field ranked among the worst. While protection is improving, none of the current or retired varsity football helmets can provide absolute protection against brain injuries, including concussions and subdural hematomas. To maximize protection against head and brain injuries for football players of all ages, the authors propose thresholds for all sports helmets based on a peak linear acceleration no greater than 90 g and a peak angular acceleration not exceeding 1700 rad/sec2.

Experimental Determination of Pressure Wave Transmission to the Brain During Head-Neck Blast Tests

2013 ◽  
Author(s):  
Kyle Ott ◽  
Liming Voo ◽  
Andrew Merkle ◽  
Alexander Iwaskiw ◽  
Alexis Wickwire ◽  
...  
Keyword(s):  
Brain Injury ◽  
Brain Injuries ◽  
Head Injuries ◽  
Strong Association ◽  
Skull Fracture ◽  
Linear Acceleration ◽  
Military Operations ◽  
Blunt Impact ◽  
Injury Mechanisms ◽  
Inertial Loading

Traumatic Brain Injury (TBI) has been the termed the “signature injury” in wounded soldiers in recent military operations [1]. Evidence has shown a strong association between TBI and blast loading to the head due to exposure to explosive events [2, 3]. Head injury mechanisms in a primary blast environment remain elusive and are the subject of much speculation and hypotheses. However, brain injury mechanisms have traditionally been attributed to either a direct impact or a rapid head acceleration or deceleration. Extensive research has been performed regarding the effects of blunt trauma and inertial loading on head injuries [4, 5]. Direct impacts to the head can largely be described based on linear acceleration measurements that correlate to skull fracture and focal brain injuries [6]. Computational head modeling of blunt impact events has shown that the linear acceleration response correlates well with increases in brain pressure [7]. Intracranial pressure, therefore, has been one of the major quantities investigated for correlation to blast induced TBI injury mechanisms [8–14].

Head Kinematics in Mini-Sled Tests of Foam Padding: Relevance of Linear Responses From Free Motion Headform (FMH) Testing to Head Angular Responses

2003 ◽  
Vol 125 (4) ◽  
pp. 523-532 ◽  
Author(s):  
J. Ivarsson ◽  
D. C. Viano ◽  
P. Lo¨vsund ◽  
Y. Parnaik
Keyword(s):  
Angular Velocity ◽  
Brain Injuries ◽  
Motor Vehicle ◽  
Sagittal Plane ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Free Motion ◽  
Constant Thickness ◽  
Head Impacts ◽  
Hybrid Iii

The revised Federal Motor Vehicle Safety Standard (FMVSS) No. 201 specifies that the safety performance of vehicle upper interiors is determined from the resultant linear acceleration response of a free motion headform (FMH) impacting the interior at 6.7 m/s. This study addresses whether linear output data from the FMH test can be used to select an upper interior padding that decreases the likelihood of rotationally induced brain injuries. Using an experimental setup consisting of a Hybrid III head-neck structure mounted on a mini-sled platform, sagittal plane linear and angular head accelerations were measured in frontal head impacts into foam samples of various stiffness and density with a constant thickness (51 mm) at low (∼5.0 m/s), intermediate (∼7.0 m/s), and high (∼9.6 m/s) impact speeds. Provided that the foam samples did not bottom out, recorded peak values of angular acceleration and change in angular velocity increased approximately linearly with increasing peak resultant linear acceleration and value of the Head Injury Criterion HIC36. The results indicate that the padding that produces the lowest possible peak angular acceleration and peak change in angular velocity without causing high peak forces is the one that produces the lowest possible HIC36 without bottoming out in the FMH test.

Potential for head injuries in infants from low-height falls

2008 ◽  
Vol 2 (5) ◽  
pp. 321-330 ◽  
Author(s):  
Brittany Coats ◽  
Susan S. Margulies
Keyword(s):  
Child Abuse ◽  
Impact Force ◽  
Head Injuries ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Objective Data ◽  
Time Duration ◽  
Impact Forces ◽  
Force Data ◽  
Peak Impact Force

Object Falls are the most common accident scenario in young children as well as the most common history provided in child abuse cases. Understanding the biomechanics of falls provides clinicians with objective data to aid in their diagnosis of accidental or inflicted trauma. The objective of this study was to determine impact forces and angular accelerations associated with low-height falls in infants. Methods An instrumented anthropomorphic infant surrogate was created to measure the forces and 3D angular accelerations associated with falls from low heights (0.3–0.9 m) onto a mattress, carpet pad, or concrete. Results Although height significantly increased peak angular acceleration (αp), change in peak-to-peak angular velocity, time duration associated with the change in velocity, and peak impact force (Fp) for head-first drops onto a carpet pad or concrete, none of these variables were significantly affected by height when dropped onto a mattress. The αp was not significantly different for drops onto a carpet pad and concrete from 0.6 or 0.9 m due to compression of the carpet pad. Surprisingly, sagittal αp was equaled or surpassed by axial αp. Conclusions These are the first 3D angular acceleration and impact force data available for head impact in infants from low-height falls. A future study involving a computational model of the infant head will use the loads measured in this study to predict the probability of occipital skull fracture on impact from head-first low-height falls. Together, these studies will provide data that will aid clinicians in the evaluation of accidental and inflicted head injuries, and will contribute to the design of safer environments for children.

scholarly journals Anthropomorphic simulations of falls, shakes, and inflicted impacts in infants

2003 ◽  
Vol 99 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Michael T. Prange ◽  
Brittany Coats ◽  
Ann-Christine Duhaime ◽  
Susan S. Margulies
Keyword(s):  
Brain Injuries ◽  
Rotational Velocity ◽  
Head Injuries ◽  
Diffuse Axonal Injury ◽  
Angular Acceleration ◽  
Concrete Surface ◽  
Human Infant ◽  
Subdural Hemorrhage ◽  
Content Type ◽  
Fine Print

Object. Rotational loading conditions have been shown to produce subdural hemorrhage and diffuse axonal injury. No experimental data are available with which to compare the rotational response of the head of an infant during accidental and inflicted head injuries. The authors sought to compare rotational deceleration sustained by the head among free falls, from different heights onto different surfaces, with those sustained during shaking and inflicted impact. Methods. An anthropomorphic surrogate of a 1.5-month-old human infant was constructed and used to simulate falls from 0.3 m (1 ft), 0.9 m (3 ft), and 1.5 m (5 ft), as well as vigorous shaking and inflicted head impact. During falls, the surrogate experienced occipital contact against a concrete surface, carpet pad, or foam mattress. For shakes, investigators repeatedly shook the surrogate in an anteroposterior plane; inflicted impact was defined as the terminal portion of a vigorous shake, in which the surrogate's occiput made contact with a rigid or padded surface. Rotational velocity was recorded directly and the maximum (peak—peak) change in angular velocity and the peak angular acceleration were calculated. Analysis of variance revealed significant increases in the and associated with falls onto harder surfaces and from higher heights. During inflicted impacts against rigid surfaces, the and were significantly greater than those measured under all other conditions. Conclusions. Vigorous shakes of this infant model produced rotational responses similar to those resulting from minor falls, but inflicted impacts produced responses that were significantly higher than even a 1.5-m fall onto concrete. Because larger accelerations are associated with an increasing likelihood of injury, the findings indicate that inflicted impacts against hard surfaces are more likely to be associated with inertial brain injuries than falls from a height less than 1.5 m or from shaking.

Child ATD Reconstruction of a Fatal Pediatric Fall

2009 ◽  
Author(s):  
Chris Van Ee ◽  
David Raymond ◽  
Kirk Thibault ◽  
Warren Hardy ◽  
John Plunkett
Keyword(s):  
Head Injury ◽  
Additional Data ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Linear Acceleration ◽  
Test Device ◽  
Critical Data ◽  
Animal Data ◽  
Injury Assessment ◽  
Accident Scenarios

The current head Injury Assessment Reference Values (IARVs) for the child dummies are based in part on scaling adult and animal data and on reconstructions of real world accident scenarios. Reconstruction of well-documented accident scenarios provides critical data in the evaluation of proposed IARV values, but relatively few accidents are sufficiently documented to allow for accurate reconstructions. This reconstruction of a well documented fatal-fall involving a 23-month old child supplies additional data for IARV assessment. The videotaped fatal-fall resulted in a frontal head impact onto a carpet-covered cement floor. The child suffered an acute right temporal parietal subdural hematoma without skull fracture. The fall dynamics were reconstructed in the laboratory and the head linear and angular accelerations were quantified using the CRABI-18 Anthropomorphic Test Device (ATD). Peak linear acceleration was 125 ± 7 g (range 114–139), HIC15 was 335 ± 115 (Range 257–616), peak angular velocity was 57± 16 (Range 26–74), and peak angular acceleration was 32 ± 12 krad/s2 (Range 15–56). The results of the CRABI-18 fatal fall reconstruction were consistent with the linear and rotational tolerances reported in the literature. This study investigates the usefulness of the CRABI-18 anthropomorphic testing device in forensic investigations of child head injury and aids in the evaluation of proposed IARVs for head injury.

Biomechanics of the toddler head during low-height falls: an anthropomorphic dummy analysis

2010 ◽  
Vol 6 (1) ◽  
pp. 57-68 ◽  
Author(s):  
Nicole G. Ibrahim ◽  
Susan S. Margulies
Keyword(s):  
Mechanical Load ◽  
Tissue Injury ◽  
Head Injuries ◽  
Skull Fracture ◽  
Angular Acceleration ◽  
Soft Tissue Injuries ◽  
Altered Mental Status ◽  
Neurological Impairment ◽  
Clinical Findings ◽  
Facial Soft Tissue

Object Falls are the most common environmental setting for closed head injuries in children between 2 and 4 years of age. The authors previously found that toddlers had fewer skull fractures and scalp/facial soft-tissue injuries, and more frequent altered mental status than infants for the same low-height falls (≤3 ft). Methods To identify potential age-dependent mechanical load factors that may be responsible for these clinical findings, the authors created an instrumented dummy representing an 18-month-old child using published toddler anthropometry and mechanical properties of the skull and neck, and they measured peak angular acceleration during low-height falls (1, 2, and 3 ft) onto carpet pad and concrete. They compared these results from occiput-first impacts to previously obtained values measured in a 6-week-old infant dummy. Results Peak angular acceleration of the toddler dummy head was largest in the sagittal and horizontal directions and increased significantly (around 2-fold) with fall height between 1 and 2 ft. Impacts onto concrete produced larger peak angular accelerations and smaller impact durations than those onto carpet pad. When compared with previously measured infant drops, toddler head accelerations were more than double those of the infant from the same height onto the same surface, likely contributing to the higher incidence of loss of consciousness reported in toddlers. Furthermore, the toddler impact forces were larger than those in the infant, but because of the thicker toddler skull, the risk of skull fracture from low-height falls is likely lower in toddlers compared with infants. Conclusions If similar fracture limits and brain tissue injury thresholds between infants and toddlers are assumed, it is expected that for impact events, the toddler is likely less vulnerable to skull fracture but more vulnerable to neurological impairment compared with the infant.

Evaluation and Refinement of the CRABI-6 Anthropomorphic Test Device Injury Criteria for Skull Fracture

2009 ◽  
Author(s):  
Chris Van Ee ◽  
Barbara Moroski-Browne ◽  
David Raymond ◽  
Kirk Thibault ◽  
Warren Hardy ◽  
...  
Keyword(s):  
Head Injury ◽  
Reference Values ◽  
Head Injuries ◽  
Skull Fracture ◽  
Linear Acceleration ◽  
Free Fall ◽  
Head Acceleration ◽  
Test Device ◽  
Impact Surface ◽  
Injury Criteria

Only sparse experimental pediatric tissue tolerance data are available for the development of pediatric surrogates and associated injury reference values. The objective of this study is to improve the efficacy of the CRABI series anthropometric test devices by increasing the foundational data used for head injury and skull fracture. To accomplish this, this study evaluated and refined the CRABI-6 injury assessment reference values (IARV) associated with skull fracture by correlating the test device response with the detailed fracture results of 50 infant cadaver drop studies reported by Weber in 1984 and 1985. Using the CRABI-6 test device, four 82-cm height free fall impacts were performed onto each of four different impact surfaces: concrete, carpet, 2-cm foam mat, and an 8-cm thick camel hair blanket. Average and standard deviation of peak head linear acceleration and HIC36 (Head Injury Criteria) were computed for each impact surface. The average CRABI impact response was mapped to the Weber fracture outcomes for corresponding impact surfaces and logistic regression was performed to define a skull fracture risk curve based on exposure. The 5%, 25%, 50%, 75%, and 95% risk for skull fracture correlated with a CRABI-6 peak linear head acceleration of 50, 70, 82, 94, and 114 g’s and a HIC36 of 87, 214, 290, 366 and 493, respectively. This study made use of the most extensive set of controlled infant cadaver head impact and fracture data currently available. Previous head IARVs for the CRABI-6 are given by Melvin (1995) and by Klinich et al. (2002). Based on a review of pediatric tissue experiments, scaling of adult and child dummy IARVs, and sled tests, Melvin suggested a HIC22 of 390 and a limit on peak head acceleration of 50 g’s. Klinich et al. reported the results of three reconstructions of airbag-related infant head injuries and three additional reconstructions not associated with head injury. They estimated the 50% risk of minor skull fracture to be 85 g’s and 220 HIC15. These previously reported estimates appear to be in agreement with the results reported from this study for CRABI-6 IARV of 50% risk of skull fracture at 82 g’s and 290 HIC36.

A Review of Impact Testing Methods for Headgear in Sports: Considerations for Improved Prevention of Head Injury Through Research and Standards

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
T. Whyte ◽  
C. A. Stuart ◽  
A. Mallory ◽  
M. Ghajari ◽  
D. J. Plant ◽  
...  
Keyword(s):  
Brain Injury ◽  
Brain Injuries ◽  
Head Injuries ◽  
Impact Testing ◽  
Test Procedures ◽  
Testing Procedures ◽  
Research Areas ◽  
Age Appropriate ◽  
At Risk Populations ◽  
The 1960S

Standards for sports headgear were introduced as far back as the 1960s and many have remained substantially unchanged to present day. Since this time, headgear has virtually eliminated catastrophic head injuries such as skull fractures and changed the landscape of head injuries in sports. Mild traumatic brain injury (mTBI) is now a prevalent concern and the effectiveness of headgear in mitigating mTBI is inconclusive for most sports. Given that most current headgear standards are confined to attenuating linear head mechanics and recent brain injury studies have underscored the importance of angular mechanics in the genesis of mTBI, new or expanded standards are needed to foster headgear development and assess headgear performance that addresses all types of sport-related head and brain injuries. The aim of this review was to provide a basis for developing new sports headgear impact tests for standards by summarizing and critiquing the following: (1) impact testing procedures currently codified in published headgear standards for sports and (2) new or proposed headgear impact test procedures in published literature and/or relevant conferences. Research areas identified as needing further knowledge to support standards test development include defining sports-specific head impact conditions, establishing injury and age appropriate headgear assessment criteria, and the development of headgear specific head and neck surrogates for at-risk populations.

Epilogue

2019 ◽  
pp. 210-216
Author(s):  
Kathleen Bachynski
Keyword(s):  
Cultural Values ◽  
Brain Injuries ◽  
Scientific Evidence ◽  
Head Injuries ◽  
Traumatic Brain Injuries ◽  
Alternative Interpretation ◽  
Return To Play ◽  
Sports Organizations ◽  
Youth Football ◽  
Adult Supervision

Contemporary debates over head injuries in youth football are at a crossroads, with competing framings of the risks of traumatic brain injuries resulting in significantly different potential responses to addressing the sport’s risks. The prevailing framework, shaped in many ways by the NFL and other sports organizations, suggests that improved adult supervision, return-to-play guidelines, better helmet design, and other similar strategies can sufficiently address the risks of youth football. An alternative interpretation of the scientific evidence on sub-concussive hits, however, indicates that the full-body collisions associated with tackling carry inherent risks of brain trauma that cannot be substantially reduced. The cultural values and meanings attached to youth football inform these contemporary debates, as well as the possible future of America’s most popular sport.

scholarly journals The Ability of an Aftermarket Helmet Add-On Device to Reduce Impact-Force Accelerations During Drop Tests

2017 ◽  
Vol 52 (9) ◽  
pp. 802-808 ◽  
Author(s):  
Katherine M. Breedlove ◽  
Evan Breedlove ◽  
Eric Nauman ◽  
Thomas G. Bowman ◽  
Monica R. Lininger
Keyword(s):  
High Velocity ◽  
Significant Interaction ◽  
Skull Fracture ◽  
Linear Acceleration ◽  
Severity Index ◽  
Impact Forces ◽  
Football Helmets ◽  
Drop Tests ◽  
Athletic Equipment ◽  
The Guardian

Context:  The Guardian Cap provides a soft covering intended to mitigate energy transfer to the head during football contact. Yet how well it attenuates impacts remains unknown. Objective:  To evaluate the changes in the Gadd Severity Index (GSI) and linear acceleration during drop tests on helmeted headforms with or without Guardian Caps. Design:  Crossover study. Setting:  Laboratory. Patients or Other Participants:  Nine new football helmets sent directly from the manufacturer. Intervention(s):  We dropped the helmets at 3 velocities on 6 helmet locations (front, side, right front boss, top, rear right boss, and rear) as prescribed by the National Operating Committee on Standards for Athletic Equipment. Helmets were tested with facemasks in place but no Guardian Cap and then retested with the facemasks in place and the Guardian Cap affixed. Main Outcome Measure(s):  The GSI scores and linear accelerations measured in g forces. Results:  For the GSI, we found a significant interaction among drop location, Guardian Cap presence, and helmet brand at the high velocity (F10,50 = 3.01, P = .005) but not at the low (F3.23,16.15 = 0.84, P = .50) or medium (F10,50 = 1.29, P = .26) velocities. Similarly for linear accelerations, we found a significant interaction among drop location, Guardian Cap presence, and helmet brand at the high velocity (F10,50 = 3.01, P = .002, ω2 = 0.05) but not at the low (F10,50 = 0.49, P = .89, ω2 < 0.01, 1–β = 0.16) or medium (F5.20,26.01 = 2.43, P = .06, ω2 < 0.01, 1–β = 0.68) velocities. Conclusions:  The Guardian Cap failed to significantly improve the helmets' ability to mitigate impact forces at most locations. Limited evidence indicates how a reduction in GSI would provide clinically relevant benefits beyond reducing the risk of skull fracture or a similar catastrophic event.

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