The description above is the CDC’s definition of traumatic brain injury (TBI). Symptoms of TBI may last a few days or a lifetime. Thought, memory, vision, hearing, movement and emotional functioning could all be impaired.
 
Most TBIs are mild (often referred to as concussions) and may result in unconsciousness or a brief change in mental status. Severe cases can lead to memory loss, prolonged periods of unconsciousness or even death. Most TBIs occur as the result of a fall, according to in-depth reports in 2014. Being hit in the head is the second leading cause.
 
These injuries are like scrambling an egg that’s still in the shell. The brain floats in cerebrospinal fluid (CSF) within the skull. If the head is suddenly jarred, the skull can move too quickly for the CSF to adjust. The brain is bruised when it hits the side of the skull. In a rotational impact scenario where the head and neck are twisted, the brain can rotate and neurons and tissues can become strained, believed to be a major factor in axonal injury.
 
That said, exact causes of brain injury are still unknown. Is it always dependent on the acceleration of the head? The force of impact? The angle or direction of impact? How does a number of sub-concussive impacts over time, such as what a football player undergoes, affect the brain? Team Wendy is actively working and collaborating with others to answer questions like these and advance society’s understanding of TBI.

Protective helmets must mitigate a wide range of impact forces, from low-energy sub-concussive blunt impacts to more serious falls and collisions.
 
First, a quick review. The human body possesses kinetic energy when in motion. Energy scatters if it comes into contact with another force or object. It’s the helmet that helps absorb this kinetic energy upon impact rather than letting your head (and subsequently your brain) take the brunt of the force. In ballistic cases, the helmet shell catches the bullet (up to a certain velocity), and the hard foam within the helmet absorbs the energy. Additional soft foam padding provides comfort and cushion.

HOW DOES A HELMET MITIGATE BLUNT IMPACT?

Blunt impact occurs when an object comes into direct contact with the head. Loads of pressure can be dispensed to the brain even if there’s no penetration to the skull. Think of tripping and hitting your head on the ground. The severity of the impact is in direct correlation to speed your head decelerates upon contact. Ballistic impact, on the other hand, comes from a small-mass object, such as a firearm bullet or projectile, moving at a high velocity before striking the head. In addition to these blunt and ballistic impact threats, there is another danger: shockwaves emanating from improvised explosive devices (IEDs), breaching devices and other blasts. The impact of the pressure wave, a phenomenon classified as primary blast injury, is another suspected contributor of brain injury. There’s also the high possibility of secondary and tertiary blast injuries from shrapnel and debris propelled by the explosion (ballistic impact) or being knocked against any nearby surfaces (blunt impact).
 
Team Wendy’s chemists and engineers test impact responses of foams and other impact mitigating structures in order to improve the protective capabilities of our helmet liners across a range of impact velocities. We develop foams with varying responses and conduct impact and compression testing both independently of a helmet and as a full system to analyze their stress-strain curve.
 
Ballistic threats present an entirely different energy mitigation challenge. Team Wendy has been involved in several R&D efforts to design and adapt novel helmet liner materials to ballistic helmets and better understand how optimization can limit trauma. Through a USSOCOM BAA funded research effort, we refined padding materials to minimize force transfer to the skull – working with kinetic energy levels that could previously be mitigated only by the hard-outer shell of the helmet.
 
In support of research to understand the issue of primary blast-related brain injury, we conduct live blast tests with new prototypical headforms. We also conducted shock tube tests on liners as part of the Army Small Business Innovation Research (SBIR) program and moderated a panel discussion on the issue with leading experts.
 
A good ballistic helmet protects against a litany of unpredictable events, including but not limited to extremely high-energy ballistic and blast threats.

The long-established method for determining a helmet’s protection against a blunt impact is to test it using a uniaxial drop tower. This, essentially, tests straight-ahead impact and we have this capability inhouse. We’re able to quickly develop and optimize materials and designs, as well as maintain a world-class quality standard for our aftermarket liner systems.
 
However, when real-world impacts occur, the head can undergo complex motions that are not well replicated by the traditional tests. Angular or rotational movement in particular is increasingly known to play a role in straining brain tissue. By considering such events, we aim to improve a helmet’s ability to mitigate concussions.
 
Team Wendy continues to conduct internal and independent testing to understand how helmet and liner designs can lessen rotational accelerations. Under a grant from the Office of Naval Research, we partner with several universities and research groups to analyze the cellular mechanisms of mTBI and link cellular response to the kinematics of head impact. The ultimate goal is to develop a helmet liner that contains built-in sensors that can collect 10,000 data points per second in order to determine levels of impact accelerations and the head injuries associated with the results.

We recently brought in a new piece of equipment in order to better understand rotational impacts. The six-degree-of-freedom triaxial impact machine is capable of capturing realistic kinematics of the head. We now gather full linear and rotational measurements instead of standard measurements from a headform constrained to linear movement.
 
Although progress is continually being made in the understanding of brain injury mechanisms, there is no single well-established rotational injury threshold, nor a standardized method for testing combat helmets against it. The new test equipment will be used to carry out impacts with a variety of different head/neck surrogate combinations. Combined with cellular study and finite element modeling, this will provide insight into what the current helmet test methods represent as well as identify areas to improve methodology and gain new insights. Team Wendy will use the data to better understand how cellular injury originates and, armed with this knowledge, we ultimately hope to develop new materials and helmet designs with a never-before-seen level improved impact protection.
 
New discoveries await, and we hope to use innovations to continue to improve what is already the most state-of-the-art protective systems on the market.

INVESTIGATING TBI PREVENTION WITH PANTHER

Team Wendy has joined forced with the University of Wisconsin-Madison, Brown University, Sandia National Laboratories, and the Colorado School of Mines in the PANTHER program to conduct comprehensive research on TBI.
 
With a $4.75 million grant from the Office of Naval Research, the three-year study aims to produce new insights into how traumatic injuries form in the brain and develop new helmet technologies to prevent injury. Accomplishing that will require a comprehensive, multilevel understanding of how forces are transmitted from helmet to skull, from the skull through brain tissue and ultimately to individual neurons and axons.
 
The effort brings together research spanning the microscopic level of brain cells to the macroscopic level of helmets. It is incredibly unique. Our team leads on the macroscopic scale, developing an integrated sensor system within the padding of a helmet that is capable of measuring linear and angular accelerations. The system will be capable of providing measurements in a lab setting, first on a test headform, and eventually on a human wearer. With new data, we can improve the standards for helmet testing so they better reflect real-life scenarios and the stresses and strains the brain experiences during impact.
 
By combining the expertise of each contributing team, the PANTHER program’s end goal is to apply foundational research in brain injury, materials research, kinematic measurement and predictive simulation to develop a new helmet that surpasses all others in protecting the brain.

IMPROVING BALLISTIC IMPACT PROTECTION WITH TALOS

 
Team Wendy was selected to work with the United States Special Operations Command (USSOCOM) in the development of an advanced ballistic military suit: the Tactical Assault Light Operator Suit (TALOS), also known as the “Iron Man Suit” due to its extreme ballistic protection capabilities combined with an exterior exoskeleton. Team Wendy’s assignment in this initiative was to design the TALOS helmet liner with the specific aim of maximizing ballistic protection while reducing blunt trauma.
 
The liner for this helmet is unique in that operators selected to wear TALOS would have a personalized helmet designed to fit a 3D scan of their particular head measurements. This advanced helmet liner system greatly mitigates ballistic backface deformation, allowing greater survivability upon impact.

ENHANCING FOAM STRUCTURES WITH NATICK

Team Wendy also worked closely with U.S. Army Natick Soldier Systems Center (NSSC) to develop a new foam structure for our helmet liner systems and comfort pads. The overall redesign of this structure is anticipated to increase the wearer’s individual modularity of fit and comfort and provide increased impact mitigation properties.