by E. Paul Zehr
In my view, exploring the bits of Iron Man that are realistic unveils the fantastic capacities the human body possesses. What is my verdict on the possibility of Iron Man? Well, it is possible if we accept a 1963 comic book version with some caveats. However, the length of Iron Man’s career would be very short. (We will look at this more in detail later in the chapter.) Tony Stark as Iron Man faces three main problems in trying to have a long life as an armored superhero: concussion, the integrity of his neural implants, and the danger associated with experimenting on and implementing of the Iron Man suit. That is, Tony Stark would likely have killed himself in some accident or during flight. Also, given the need for direct nervous system connection, all the health issues associated with implanting man-made materials into the body would severely limit his ability to have a long career.
What Does Getting Whipped around by Whiplash Do to the Man within Iron Man?
Concussion is a huge issue for Tony to get past. Tony stated this very plainly in the 2010 graphic novel Iron Man: The End: “All those years trusting my armor to protect me, I forgot there was just a man inside. That pummeling took a toll. Degenerative nerve damage eating away my coordination like a boxer after too many shots to the head.” Very graphic stuff, even for a graphic novel. And very true. Recently concussion in sports has received a lot of attention. Some years ago the NFL got quite serious about addressing concussion in football, particularly as it affected the marquee quarterback position. More recently the issue of concussion has—finally—received more attention in the high impact sport of ice hockey. There is still a long way to go when it comes to a widespread change in attitude.
I really enjoy hockey and football, and this past year I was watching Hockey Night in Canada on the Canadian Broadcasting Corporation (CBC’s Hockey Night in Canada is the NHL equivalent of NFL’s Monday Night Football). At the end of the Montreal Canadiens versus Toronto Maple Leafs game (if you’re not familiar with ice hockey, you can think Washington Redskins and Dallas Cowboys to get the NFL equivalent, or Manchester United versus Liverpool for the English football equivalent, of the rivalry), one of the co-hosts in a between-period segment presented an overview of the night’s major head injuries in a short video montage. Following this the host managed a kind of weak joke about squashed melons (or something similar to that—the key word was squash, it being Hallowe’en and visions of pumpkins were in the air I guess. Ha ha.). Another co-host laughed but clearly mostly out of pity, as he looked quite uncomfortable.
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 seve
re 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.
Integrity of Implants in Iron Man
Please think back to the revision of the origin story I suggested for Tony (have a peek back at chapter 7). Along with this revision is the corresponding implication that the use of the implantable cardioverting defibrillator (ICD) has for his activity as Iron Man. One of the controversies around ICDs, though, is how active people should be if they have an implantation. Typically, aggressive contact sports or vigorous exercise are not recommended for those with ICDs. There is concern over how well they would function in such cases and concern over inappropriate shocks occurring. That means that the function of the defibrillator itself could interrupt normal heart rhythm during extreme activity and lead to more significant problems. So, the upshot of all of this is that Tony Stark would likely have a difficult and dangerous time being Iron Man. He is clearly subjected to very vigorous exercise and extreme contact—for example getting smashed around by Iron Monger as in the first Iron Man movie. This would definitely lead to the possibility of inappropriate shocks, or, more importantly, increased breakdown of the electrical leads used to provide the shocks for restoring heart rate.
Normally, there can be a steady increase in failure rate and problems eight to ten years after implantation of a cardioverting defibrillator. This means the best case is that Tony may well need another implant after about a decade. However, his work as Iron Man clearly isn’t the “best case” for long-term stability and integrity of the ICD. How much it would be shortened is almost impossible to determine, because the data aren’t really available on how the kind of violent activity that Iron Man experiences may affect the lifespan of ICDs. However, there is some research on the need to replace cochlear implants for hearing restoration. After an implantation of a cochlear implant, current technology only sees a 5% chance of needing a replacement (called “revision” or “reimplantation”), which seems pretty good. Of interest and very relevant for what we have just been talking about, is that almost half of the cases wh
ere hardware failure has led to a revision surgery have involved a history of head trauma! So, all the bashing around we were just talking about clearly is quite hard on brain-machine interface.
Another consideration is the integrity of the nervous system and the electrode connection that would be necessary for the full integration of the suit needed for realistic use. It should be remembered that it is very difficult to interface technology with biology. Based on state-of-the-art experiments with different animals, it seems only about 50% of implanted electrodes can be usefully employed. Of those that could be used, there is a significant reduction in “usefulness” over time. This is largely due to a process known as encapsulation or “reactive gliosis”—a type of scarring of the nervous system—associated with immune rejection. Think of the medical intervention needed to keep the body from rejecting a transplanted organ. Now imagine that instead of an organ a piece of machinery has been implanted into the brain.
Jennie Leach and colleagues describe the view that the bodily response to an implanted neuroprosthetic interface has a rapid acute response, characterized by injury, inflammation, and what is known as “microglial activation.” Nerve cells are neurons and other stuff. In the other stuff category we find glial cells. Microglia make up about 20% of glial cells in the brain and provide the main protective immune response cells in the brain and spinal cord. They are a kind of “macrophage,” which means they attack and digest invaders and foreign objects in the nervous system and are the first and main form of active immune response in the brain and spinal cord.
The immune response is typically to digest an intruder and, if it cannot be digested, to cover it up so that it can do no harm. Implanted electrodes cannot be easily destroyed so the cover-up process is instead the main outcome. This begins in the acute phase and continues in a chronic response, which results in the formation of a virtually impenetrable glial or fibrotic scar around the implant. An example of this cascade of events is shown in figure 9.4. Panel A shows the implantation of an electrode array (“Utah array”) inserted through the brain and implanted on the surface of the brain. The drawings in panels B through D are close-ups of the region right beside the implant (shown as dashed rectangle in A). Cellular organization in the cortex is shown prior to implantation (panel B), immediately after implant (“acute,” panel C), and in chronic implantation (panel D). The key point is that there is steadily increasing scarring of support neurons (glia), shown at the far left near the implant surface, and some death of neurons, largely related to inflammatory responses.