Vulnerability of the Human Brain

"Instead of looking just at how the head is moving, we can visualize what's happening to a representative brain model inside the head."
"It's next-level information that can be used to validate the computer models used in helmet design."
"We're trying to understand the specific injuries that the cells undergo when the brain stretches. We want to know how the stretch and pull response of the brain might lead to injury and, specifically, where those injuries might be occurring." 
"We want to understand the critical limits of what those cells and those structures can take before they're affected."
"The brain is a very complex system and understanding exactly what leads to injury is not a trivial matter. We're still developing that understanding."
"The ultimate goal of this research is to change the way helmets are designed to improve helmet response, and also to influence in the longer term how helmets are evaluated and the safety standards applied to them."
Oren Petel, researcher, mechanical and aerospace engineering, Carleton University, Ottawa

Folds in a human brain. David Duprey / AP

"In hockey, you don’t see people dying from a hit to the head, and that is because the helmet works reasonably well for catastrophic injury."
“Football, you do get some deaths, but it’s fairly well-managed or mitigated. But neurological disease and concussion are not managed very well by a helmet. So this data will be very helpful for us; it will get us precision. The better data we get to capture the risk of concussion, the more innovation we can do in terms of helmets to reduce that risk."
“So, when we look at trauma related to neurological disease, we are only validating part of the brain and its response to trauma. This study is going to give us a really good opportunity to map different parts of the brain. . . . We are going to be able to get into parts of the brain we think are really important in terms of predicting risk."
"The brain is mostly water, so it doesn’t compress, but it does shear. It’s like jello. You can’t compress jello easily but you can shear it. And when you shear it, you damage it, and that is what is happening in the brain."
"We’re trying to understand trauma associated with sport that put athletes at risk for neurological disease. We connect the trauma to disease."
Dr. Blaine Hoshizaki, director, Neurotrauma Impact Science Laboratory, University of Ottawa

Although research into concussion has advanced in the last ten years more is required to understand what happens in the brain when a high-speed collision occurs. The design of a helmet to increase protection against injury is a high priority. Professor Petal aspires for the research he is engaged with to ultimately ensure greater safety for athletes in sports competitions such as hockey and football. From his position at Carleton University, Professor Petal applied for funding to develop a design he came up with, an X-ray system, and an impact research laboratory.

He found that funding with the Canada Foundation for Innovation and the Ontario Research Fund which came up with the required funding, and at a cost of about $320,000, both the lab and the X-ray system were completed in the space of two years. Ongoing research of Professor Petel's lab has brought contributions to his work from the Canadian Institutes of Health Research and the Natural Sciences and Engineering Research Council.

The completed laboratory is lined with lead to enable his very special type of research, equipped with a linear impactor, capable of delivering a head blow at 12 metres per second. An X-ray system capable of capturing images of the collision at 100,000 frames per second complete the major constituents of this very specialized research lab where Professor Petel and his research team are able to recreate what occurs with a helmet -- and the brain it protects -- during a high-speed collision.



The high-resolution images produced by the X-ray system lend themselves to the creation of a video -- known as cineradiography -- that illustrates interaction between a helmet and a head while at the same time revealing the physical response of the brain to an impact; the manner in which the brain compresses, twists and stretches. This revealing process and the information it contains will lead researchers in their work of designing improved helmets for hockey and football players, soldiers and cyclists.

In partnership with Defence Research and Development Canada, one project is to test what occurs to a synthetic brain within a plastic head model where markers are implanted inside the artificial brain for the purpose of measuring how it deforms in a collision. Yet another project in collaboration with Carleton neuroscience professor Matt Holahan is how pig brains [taken from an abattoir] respond to an impact. Validation of computer models commonly in use in head-injury research, another project.

When Dr. Petel studied at McGill University, he immersed himself in blast research when he joined the Shockwave Physics Group there. "It just sounded like a lot of fun, things impacting each other. And it was really challenging. Your experiments typically last several microseconds, several millionths of a second, and you have to collect all your data in the time before your experiment is destroyed", he explained.

He studied the response of ballistic armour and allied protective materials to an explosion, becoming ever more interested in the dynamics of blast injuries of what was occurring internally when a body was hit by a shock wave. And what made the lungs and brain so susceptible to injury, along with the question of how the tissue was becoming deformed. Which led the researcher to the conclusion that answers to those questions could improve protective equipment design.

As he initiated his study into injury biomechanics, at a conference years ago he questioned an experienced researcher why it was that more information relating to the reaction of internal tissue to a blast wasn't available. The response was there was no known way to measure what was happening at such high speeds. "So why isn't someone developing something to measure this?", he asked. "If you think you're so smart, why don't you do it?" was the comeback. So he set about to do just that.

Here, he sets up a machine that hits the “head” with great velocity from which he can measure impact and damage to the head. Julie Oliver / Postmedia