Inventing Iron Man (26 page)

It made me wonder if we are so desperately out of touch with the grave consequences of neural damage that can be inflicted and evidenced by concussion that it remains the stuff of jokes. If so—and based on the evidence this is indeed yes—why is that? Is it simply because we cannot see it? What I mean is, clearly, we can see the effects of concussion. What we cannot see is the actual damage to the brain, the changes in energy demand and energy delivery and the disordered activity of the neurons. A schematic illustration of what happens with a concussive event is shown in
figure 9.3
. Panel A of the figure shows the head impacting an object and the motion of the brain within the skull. When the head hits a solid object, the brain moves forward and then contacts the inside of the skull. This is the case whether the head (or helmet of Iron Man) hits a solid object or is hit by something. The relative motion is the same and gives rise to the mechanical impact of the brain. A head-first incident like the one shown in the figure is experienced first on the “front” of the brain (frontal cortex) and then secondarily on the back of the brain (occipital cortex). The second impact is called “contre coup.”

Strong head trauma provokes a cascade of events that leads to an energy crisis—kind of a malevolent neuronal oxygen debt—that causes the neurons in the brain to fail. This is shown in panel B of
figure 9.3
. The increase in energy demand, coupled with reduced blood flow and reduced metabolism, leads to the death of some nerve cells. Neurons will also take several days to recover from this massive shift of activity. The memory problems and mental fuzziness and confusion seen during this time after concussion occur because of what has happened at the cellular level. Returning to normal concentrations of neurotransmitters can sometimes take up to two weeks.

Figure 9.3. A schematic of what happens with a concussive event. The head impacting an object and the motion of the brain within the skull (
A
). When the head hits a solid object, the brain moves forward and then contacts the inside of the skull. The effects of concussion on energy demand, metabolism, and blood flow in the brain (
B
). The key period when Tony must avoid additional concussive event is indicated at the top of the panel. Panel A image courtesy of Patrick J. Lynch; panel B data redrawn from Shulman (2000).

I can personally vouch for these effects due to an accident I had during the editing of this book. I suffered a “mild” concussion and for about ten days it felt like I was two steps behind everything that was happening to me. I was exhausted, had difficulty concentrating, and generally was out of sorts. Then, it slowly went away. It felt like a mist being burned off by sunshine. I felt better and better. But it took those many days for all those ions and neurotransmitters to get back to their appropriate levels.

Some of the main areas of the brain that are most affected by repetitive mild head trauma are the hippocampus as well as the frontal lobes. These areas are very important for memory formation and storage and for movement control. Unfortunately, these brain areas are also particularly sensitive to the large changes in gravitational forces that occur during the rotation of the head in a concussive event. Rest assured that Iron Man in action experiences “concussive events” on a daily basis.

This type of injury is a real occupational hazard in contact sports like hockey and football. In the NHL another high profile incident happened in 2011. The league's star player Sidney Crosby of the Pittsburgh Penguins received a strong shoulder (and hard plastic shoulder pad) in a blind-side hit. He was knocked down and looked a bit unsteady and concussed as he stood up and skated back to the bench. He was cleared to return to play. Then, six days later, he was hit against the boards and suffered another concussive incident. He was knocked out of playing for the entire season.

Concussion really is a hot button topic. In 2009, the Associated Press published the results of an informal survey of NFL players conducted in November of that year. The AP surveyed 160 NFL players about their experiences with concussion. The survey included a mix of rookies to 17 year veterans and those playing all positions. Thirty of those players, that is, just under 20% of those interviewed, revealed that they had either not disclosed or trivialized their own concussions. Additionally, half of the players indicated they had experienced a concussion, and just over one-third of the players said the concussion had forced them to miss playing time. This information matches that from the Canadian Football League in 2000, where approximately 50% of players indicated they had experienced a concussion.

It is now much more widely understood that the brain has tremendous adaptive abilities. The nervous system really does have a “plastic” ability to respond to training or to compensate for damage. This is critical because, when we are talking about concussion, the main point that must be understood is “compensation,” which is really another way to say “repair.” A good repair means things still work well but does not mean things are the same as before the repair was either needed or finished. There is only so much repairing that can go on until limitations arise. These limitations should not be ignored or celebrated in Iron Man's world or in our own. Also, since Iron Man is repeatedly battling multiple foes and being blasted more than once, we need concern over repeated concussion.

When someone hasn't yet fully recovered from the initial concussion and then suffers another blow to the head, a very dangerous “secondary impact” syndrome can develop. Then, even a minor impact can trigger a further and more dramatic change in the regulation of blood supply to the brain. This response can lead to swelling and blood pooling and very often is fatal. A less severe outcome of multiple concussions can occur even when there has been recovery after each concussion but the concussive impacts are repeated. Often this is called “post-concussion syndrome” but anecdotally most of us know it as being “punch drunk.” It was historically named this because it was noticed initially in boxers who do absorb many blows to the head. As Tony Stark remarked above in the quote from
Iron Man: The End
, he really has had significant damage to his nervous system from all the trauma he has experienced. Your brain has tremendous capacity for change and recovery, but eventually those limits will be exposed.

Clearly, concussion and brain trauma is a constant danger for Iron Man. This is not so much from being body checked or tackled—although that would still contribute. Especially being tackled or checked or bashed by Whiplash or Iron Monger—but more being bashed into things. Or even surviving the g-forces associated with taking off and flying around. Rather, in the world of Iron Man he is constantly being bombarded and blasted. In fact, this is in a story found in the 2007
Iron Man: Hypervelocity
graphic novel. Tony talks about how harsh the effects on the body are when using his older suits compared to his newer versions: “No more soft, wet, organic brain sloshing merrily against the inside of a bony cranial vault means no more troublesome concussions. Also, a welcome respite from post-concussion vomiting into my helmet.”

To be honest, the structure of the Iron Man suit doesn't provide much protection against concussion for the head. Have a peak back at the thin face plate shown in the action figure in
figure 1.4
. This wouldn't be very helpful in reducing impact forces. As shown at the bottom of
figure 9.3
, it is important Tony Stark not receive another concussive incident for at least a week to avoid potential serious injury. However, this would be hard to avoid. For example, during the climactic battle with Iron Monger near the end of the 2008
Iron Man
movie, I estimate that Iron Man receives seven concussive events within the span of one minute. Forget about resting between concussions for seven days! Those concussive events included slamming into a car, being pummeled by Iron Monger, being slammed into a bus, and a concussive event from a blast. Let's return to the bomb suit concept and blast injury.

Here I want to focus specifically on the primary blast wave and how it affects the brain, particularly on the impact of blasts on military personnel. (You can refer back to
figure 7.2
for an illustration of the extreme pressurization and impact.) Ibolja Cernak and Linda Noble-Haeusslein have conducted some excellent work in this area, which is also known as “blast-induced neurotrauma.” This is a very important field of study, given the steadily increasing numbers of military personnel suffering this kind of injury. It has been estimated that almost three-quarters of the U.S. military casualties from Operation Enduring Freedom in Afghanistan and Operation Iraqi Freedom were caused by explosive weapons. Additionally, civilians are also routinely injured in blast-induced accidents of a similar kind. For the military personnel, protection from the blasts themselves would be a key advance. We touched on this briefly when discussing bomb disposal suits. In that context, protective suits are very useful for guarding against shrapnel. However, here we want to talk about the long-term effects of using an Iron Man suit in combat and being subject to multiple blast incidents. The protection from shrapnel using body armor may actually make the effect of the blast wave worse! The high density and rigid body armor can act as a good interface for transferring the energy of the blast wave to the wearer and by concentrating the blast energy as it moves into the body.

While this may seem confusing, think of an example using sound waves in music. Imagine listening at a door outside a room where loud music is being played. If the door is a hard surface (like a normal door), you could press your fingertips to the door and clearly feel the vibrations. The rigid door transfers the kinetic energy of the sound
waves into vibration you feel with your fingers. If the door is covered with soft rubber and you try the same thing, you won't feel much at all. The soft rubber isn't a good conductor in this case. So, it shouldn't be that surprising that while penetrating injuries are reduced with body armor, blast wave injuries have increased.

Damage to the nervous system from the blast wave occurs in several different ways. When the blast wave arrives, it may move directly through the skull and cause a rapid rotation of the head. This is similar to the general mechanism of injury in a concussion. Moving at about the speed of sound, kinetic energy in the blast wave can be transferred to the fluid component of the body in the main blood vessels in the trunk, where it is then transferred to the nervous system. This action results in damage and destruction of neurons as well as interruption in the functions of the neurons and connections in the brain and spinal cord.

Based on work in many different species from rat to monkey, blast injuries that are non-fatal decrease ability to perform work or exercise, reduce hunger and appetite, can induce spasm of the blood vessels, reduce brain activity including memory and the ability to perform movement, and can cause swelling in the brain. These effects continue to be amplified by repeated exposure to new blast events. In many ways you can think of this as being like the cumulative effects of concussion that we talked about above.

It is clear from this that for Iron Man to have a long and neurologically intact career he must limit his blast exposure to almost nothing. A simple reading of any Iron Man comics or viewing of
Iron Man
or
Iron Man 2
, show this clearly is not the case. A good analogy is one I often use when describing physiological systems. If we compare your body to a computer operating system, with rare exceptions your physiology is a Macintosh, not a PC. With a PC you tend to find out and experience many little crashes and some big crashes too. With a Mac you are typically spared the little crashes and small errors are compensated for and hidden from you the user. That is, until they become too big. At that time, the Mac crash is humungous and can be catastrophic. Your body is like that in the sense that your systems adapt to stresses and compensate for damage until you are stretched very thin. Then catastrophic failure in the body can occur.