Head Trauma on the Modern Battlefield

Defense and law enforcement personnel must be prepared for any situation. Impact explores how lightweight, comfortable personal protective equipment helps keep operators focused on the mission with reduced risk of traumatic brain injury.

From Special Operations Forces under fire to SWAT teams responding to an incident on the street, the operator must have complete confidence in their personal protective equipment (PPE). A moment’s hesitation in response caused by an an issue with their PPE could jeopardize an entire mission or result in personal injury. PPE must be
rugged and reliable, should use the most advanced technology available, protect the end-user from potential threats, and be as comfortable, mobile and lightweight as possible.

An integral feature of an operator’s PPE set-up is the ballistic helmet. During the early 20th century, helmets were little more than upturned metal dishes with a thin layer of web strapping: cumbersome, heavy – some weighing more than 3.5lbs – and uncomfortable. However, a rapid increase in the mass and velocity of ballistic threats such as bullets and shrapnel led to higher casualty rates during World War II and brought greater focus on the role of head protection.

Understanding Modern-Day Threats

An integral component of an operator’s PPE kit is the helmet, which offers critical protection against threats including ballistic impact from arms fire and explosive devices, blunt impact from falls or contact with solid objects, and blast overpressure from explosive devices.

The helmet’s core components include an external hard shell, an internal liner and suspension system to achieve a customized fit and minimize acceleration and deceleration of the head while providing comfort, and a retention device such as a chin strap to secure the system to the wearer’s head.

These components work together to reduce the risk of injury by preventing penetration from a ballistic impact and absorbing energy from a blunt impact or blast event – any of which can lead to traumatic brain injury (TBI), where the brain’s normal function is disturbed.

The threats faced by modern-day defense and law enforcement officers fall into three categories:

  • Ballistic impact from artillery, small arms fire, mines, mortars and improvised explosive devices. Consequences include penetrating wounds and behind-armor blunt trauma.
  • Blunt impact from falls, vehicle crashes, parachute drops and impacts with solid objects and the ground. Consequences include closed and open head injuries, skull fractures, hematomas and brain contusions.
  • Blasts from bombs, artillery and improvised explosive devices. Consequences include brain trauma, hematomas, contusions and diffuse axonal injury, a tearing of the brain’s long connecting nerve fibers when the brain shifts and rotates inside the skull.

All these threats have the potential to cause traumatic brain injury (TBI), which results from an impact, penetration or rapid movement of the brain inside the skull, disrupting its normal function. TBI can be the consequence of a direct bump or blow to the head, or a non-impact force such as a blast wave causing the head to jolt violently.

For law enforcement officers, the principal causes of TBI are falls, vehicle crashes and blows to the head from foreign objects. Among service personnel, analysis by doctors at the Walter Reed Army Institute of Research1 found that 60 percent of those wounded in Iraq or Afghanistan by an explosion, a vehicle accident or fall, or a gunshot wound to the face, neck or head, suffered TBI. More than 380,000 active duty military personnel sustained a TBI between 2000 and 20172.

The Causes And Consequences of TBI

Most cases of TBI are mild concussions causing a momentary loss of consciousness. More severe cases involve a period of unconsciousness or amnesia.

The signs and symptoms of mild TBI include headaches, blurred vision, dizziness, nausea, fatigue, sleep impairment, problems with speech, mood changes and anxiety.

Moderate to severe TBI can manifest itself through any of these, as well as more complex symptoms that may appear hours, days or even weeks after a head injury: dilation of one or both pupils, loss of coordination, numbness in fingers and toes, slurred speech, profound confusion, convulsions or seizures, and a state of agitation and aggression. In some cases, moderate to severe TBI can lead to longer-lasting physical, cognitive or emotional trauma.

Military service members and law enforcement personnel are often exposed to blasts in training and operations, including the shockwaves that follow a blast such as during an explosive forced entry. Blast shockwaves create a sharp increase in pressure moving through the brain, damaging cells, compromising blood vessels and causing brain inflammation. The accepted ‘safe’ blast pressure threshold is 4 pound-force per square inch (psi), used to determine stand-off distance, but an operator may encounter multiple ‘safe’ blast events, giving a cumulative negative effect. ‘Breacher’s brain’, as the condition is known, can lead to symptoms similar to concussion including headaches, dizziness, fatigue, memory problems and sleep disturbance.

Research by the National Center for Post-Traumatic Stress Disorder (PTSD) shows that the primary cause of TBI in veterans of Iraq and Afghanistan was a blast, followed by a combination of a blast plus a motor vehicle accident3. Blast exposure can accelerate brain ageing, leading to long-term conditions that affect quality of life and job performance, as well as increasing the risk of early-onset Alzheimer’s and other neurological disorders.

Reducing the End-User Burden

The defense and law enforcement sector poses unique challenges, according to Thomas Lavalle, 3M’s Global Vertical Marketing Manager for Defense, PublicSafety and Health Care: “We have to understand the mindset of end-users, whose priorities are to complete the mission, then be sure the personnel in their team are safe, then get themselves home safe last. This approach begs a vital question: what does safety mean to the individual? It’s not simply what they’re wearing – it’s their knowledge that what they’re wearing will equip them to perform their operations as efficiently as possible. In summary, to deliver lethality, mobility and survivability.”

The core components of a helmet are an external hard shell, an internal liner and suspension system to achieve a customized fit and minimize acceleration and deceleration of the head, internal padding to provide impact protection and comfort, and a retention device such as a chinstrap. Some include external rail sections to mount accessories. A helmet’s fundamental purpose is to reduce the risk of head injury by preventing penetration from a ballistic impact, and to absorb energy from a blunt-impact or blast event.

Ounces equal pounds, and pounds equal pain, Hence the critical need to drive weight out of every element of the helmet shell design
Bill VanMullekom, D3O

Brandon, an instructor with combat immersion training provider ArmorCorps and a former US Marine, has first-hand experience to support that view: “Moving into the back of a troop carrier, my body inverted and I landed with all that weight on the top of my head. Were it not for my helmet, my injuries would have been a lot worse.”4

“Serving officers trust that their PPE will do what it is designed to do, every time, without failure,” says David Jackson, US Defense Program Manager at D3O, who has more than 25 years of defense experience including eight years in the USMC Infantry and seven years with SWAT K9.

The average US military warfighter carries at least 60lbs of gear, with an extended patrol often double that figure. Every component and accessory increases the total weight, which is particularly felt when added to the helmet.

“A common adage is that ounces equal pounds, and pounds equal pain,” says Bill VanMullekom, Executive Vice President of D3O, LLC, who leads the defense and industrial PPE sectors for D3O. “Extra weight is a burden for a soldier or law enforcement officer. They must execute the mission without being distracted by their own comfort level and fatigue. Their helmet will likely need to accommodate accessories including night vision devices and communications packages. Hence the critical need to drive weight out of every element of the helmet shell design.”

In late 2016, the US Army started early field trials on a new helmet to meet the requirements of its Soldier Protection System (SPS) Integrated Helmet Protection System (IHPS). This helmet gives soldiers best-in-class protection, while also reducing the total weight of their personal protective equipment5.

The aim of the IHPS is to provide a lighter ballistic helmet capable of dealing with modern-day threats. Features include full head, face and jaw protection; passive hearing protection against explosions, gunshots and flashbangs; and improved blunt-impact performance. The modular design allows for the up-armor capability of a ballistic applique, a ballistic visor and ballistic mandible guard to enable the solider to scale protection to the threat or mission. 

“Considering the current global environment, there is tremendous interest in procuring improved head protection," says Terry Griffith, Defense and Law Enforcement Global Business Unit Manager with 3M Advanced Materials Division. "Ceradyne Inc., a 3M company, has proven expertise in providing innovative, lightweight head protection systems that keep the users safe from a variety of threats including explosive devices and rifle bullets.”

Drawing on this expertise, the US Army awarded Ceradyne a contract to deliver the Integrated Head Protection System (IHPS). “The IHPS is the first helmet system to offer the soldier a much higher level of protection against blunt impacts without sacrificing the highest level of ballistic protection to weight,” says Griffith.

Serving officers trust that their PPE will do what it is designed to do, every time, without failure.
David Jackson, D3O

Responding to evolving threats

“Our approach is to work with customers and end-users to understand the threats and risks they face, and the standards and specifications we are required to achieve,” says Vasilios Brachos, Senior Defense Product Development Manager at 3M. These include the National Institute of Justice voluntary equipment performance standards, of which three are for helmets: ballistic, riot and crash (the last relating to motorcycle helmets).

As 3M’s Thomas Lavalle explains: “These standards specifically state that there is no blunt-impact protection requirement in the ballistic standard, and no ballistic requirement in the riot standard. This presents a challenge to the communities who are identifying threats (both existing and that could emerge) and correlating them to the industry standards. Driving this insight into industry helps the procurement teams to understand the end-user’s environment in order to develop their requirements and make informed decisions. We are then able to push the technology envelope on design and manufacturing, and work with our industry partners, such as Delta Three Oscar, to explore enhanced impact protection.”

“We have learned that legacy impact liners and pads cannot keep up with evolving threats,” adds David Jackson of D3O. “As we move from the requirement for a helmet to resist an object with an impact speed of 10 feet per second to 14 feet per second and beyond, it’s vital that the helmet shell and suspension pads work together. In addition, the geometry and mass of a helmet’s accoutrements can affect its blunt-impact protection and comfort.

“Delta Three Oscar has the proven capability to adapt products to end-user needs so they can wear this equipment without sacrificing blunt-impact protection,” Jackson continues.

“Our system delivers reduced transmitted forces overall, a reduction in the inertial mass of the helmet to minimize head acceleration, and quicker recovery times to maintain protection between a first and second impact. The unique application of D3O® allows us to evolve and develop these aspects while optimizing protection in our partners’ helmet designs and geometry.

“For the end-user, Delta Three Oscar gives the peace of mind of knowing that what we make far exceeds the specification so service personnel can focus on the task at hand, enhancing survivability and enabling the successful completion of the mission.”

The Challenges of Law Enforcement

“More and more law enforcement officers are now wearing head protection similar to that worn by the military,” explains 3M’s Thomas Lavalle. “As US Special Forces began to operate in more urban warfare environments we have seen a share of common tactics and approaches in domestic law enforcement. Equipment has been part of that.”

“As well as delivering on ballistic performance,” adds Vasilios Brachos
of 3M, “the interoperability requirements of the modern military helmet, where it interfaces with a range of other devices, has a direct crossover to law enforcement. There’s a constant flowdown of core technology.”

In the same way that bulletproof vests have become a key component of PPE for law enforcement officers, ballistic helmets developed with attention to weight, ergonomics, modularity, comfort and the appropriate level of protection should follow. Indeed, advanced, fit-for-purpose headgear could be the difference between a police officer addressing the threat posed by an armed assailant or becoming another casualty themselves.

Innovation to Create Efficiency

The last ten years have seen huge leaps forward in head protection for
law enforcement and military applications. This technological advancement is unlikely to slow down.

New materials, geometries and optimized design will continue to drive innovation. These innovations, coupled with enhanced manufacturing equipment and methodologies, will bring performance gains in head protection. “We have found ways to lay the pads in the helmet to increase the number of contact points with the head, thus maximizing comfort,” Bill VanMullekom of D3O explains. “In future, instead of a number of separate pads, what about a modular impact protection system that slips into a helmet shell? Or sub-components integrated around a suspension system?”

“In terms of future innovation,” says Vincent Borbone, Product Development Specialist at 3M, “the fundamental requirement probably will never change: the most protection at the lowest weight. By constantly reviewing every step of the manufacturing process, every raw material that goes into the product, and keeping our focus on design optimization, we can achieve that goal of increased performance over weight. It’s fair to say that we scrutinize every component and count every ounce in order to achieve those four key aims: lethality, mobility, survivability and sustainability.”

“We have many, many different variables creating little tiny stresses on us as operators,” concludes former US Marine, Brandon. “Many of those stresses tend to come from helmets. Everything we can do to lower those stresses – to make our equipment slightly more comfortable, slightly lighter, one less thing we have to worry about – at the end of the day it makes us more efficient.”7 

TRUST Stratus™ Helmet Pad System

Designed for high performance and comfort, TRUST Stratus™ is the latest, most advanced commercial helmet pad system from Delta Three Oscar.

Drawing inspiration from our solutions for the United States Army, TRUST Stratus™ utilizes the full potential of D3O’s rate sensitive properties to simultaneously meet impact performance requirements at 10 and 14 feet per second.

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