6 months ago

GSN Magazine June 2016 Digital Edition

Hazmat Science and

Hazmat Science and Public Policy with George Lane had the same pattern of scarring in the same places, which appeared to correspond to the brain’s centers for sleep, cognition and other classic brain-injury trouble spots. Then Perl made an even more surprising discovery. He examined the brains of two veterans who died just days after their blast exposure and found embryonic versions of the same injury, in the same areas. The development of the injuries seemed to match the time elapsed since the blast event. Perl compared the damaged brains with those of people who suffered ordinary concussions with others who had drug addictions, which can also cause visible brain changes, and a control group with no injuries at all. None in control groups had the mold-like pattern. Perl’s findings were recently published in the scientific journal “The Lancet Neurology”. 6 His discovery may solve a medical mystery first observed in the trenches of World War I, first called “shell shock”, then “combat fatigue”, and now “Post- Traumatic Stress Disorder”, “PTSD”. In each case, it was considered psychic rather than a physical affliction. Only recently have neurologists, physicists, and senior officers pushed back at military generals that had told soldiers diagnosed with PTSD to “deal with it,” fed them pills, and then sent them back into battle untreated. If Perl’s discovery is confirmed by other scientists, and if short-term signatures caused by blast are confirmed to be a pattern of scarring in the brain, there could be significant implications for both the military and the medical community. Much of what has been described as emotional trauma may be reinterpreted, and many veterans may demand recognition of an injury that cannot be definitively diagnosed until after death. There will be calls for more research, drug trials, better helmets, and expanded veteran care. The disturbing message behind Perl’s discovery is that modern warfare destroys soldier’s brains. A blast wave generated by an explosion starts with a single pulse of increased air pressure that lasts a few milliseconds. Negative pressure, or suction, immediately follows the positive wave. The duration of the blast waves depends on the type of explosive and the distance from the point of detonation. The blast wave expands as a sphere of compressed gases, which displaces an equal volume of air at a high velocity. It compresses air and then falls rapidly to negative pressure in milliseconds, generated by the mass displacement of air by expanding gases. It may accelerate to hurricane force. The blast 16 wave is the main cause of blast injury. The effects of blast on the human body are complicated. People who have been exposed to blasts at close range describe it as overpowering. Many soldiers do not recall the moment of impact, lost in the flash of light, and the deafening sound or unconsciousness. Those who do remember it recall it as intensely violent. Trinitrotoluene, or TNT, was first used in artillery shells by the German Army in 1902. These weapons were used by all sides soon after the First World War started in 1914. TNT created a level of violence far beyond the cavalry charges of previous wars. British doctor Dr. Frederick Mott

elieved that “shell shock” was caused by a physical wound and proposed dissecting the brains of affected soldiers. He predicted the mechanism of blast effects in a paper published in The Lancet in February 1916 in which he said blasts caused “physical or chemical change and a break in the links of the chain of neurons which serve a particular function.” 7 Most other doctors saw “shell shock” as emotional trauma. Sigmund Freud and other psychologists began developing theories about how the mind responds to stress. Soldiers suffering from “shell shock” were often described as possessing “a neuropathic tendency” or even “a lack of manly vigor and patriotic spirit”. 8 In 1980 “shell shock” became known as “post-traumatic stress disorder” (PTSD), reflecting the social and emotional strain of returning veterans of the war in Vietnam. It was known that blasts had powerful and mysterious effects on the body. Starting in 1951 the U.S. government established the “Blast Overpressure Program” to investigate the effects of large explosions, including atomic bombs, on living tissue.9 At that time, scientists believed blasts would mainly affect air pockets in the body, like the lungs, the digestive system, and the ears. However few asked about the effects on the brain. In the early 1990s, Dr. Ibolja Cernak, who grew up in what is now Serbia, was working as a doctor and researcher at a military hospital in Belgrade, treating large numbers of soldiers with blast trauma, usually from mortars and artillery fire. As in World War I, men often suffered mental impairment but few visible wounds. Dr. Cernak collected blood samples from soldiers around the battlefields of Bosnia and Serbia for several years, cataloging the neurological effects of blast on over 1,300 soldiers. “The blast covers the entire body,” she said. “It has a squeezing effect. Ask soldiers what they felt: The first thing they say is that their ears 17 were popped out, they were gasping for air, like some huge fist is squeezing them. The entire body is involved in that interaction.” 10 Cernak believed that blast ripples moved through the body like rings on the surface of a pond. The speed of the ripples changes when they encounter air pockets with different density at the borders between the gray and white matter of the brain, and inflict greater damage in those places. Physicists later theorized how blast damages the brain, including surges of blood from the chest, pressure on brain tissue, and the centripetal forces of the brain bouncing back and forth inside the skull as in concussions. Charles Needham, a renowned authority on blast physics, wrote that post-mortems on blast injuries supported these theories. 11 More powerful roadside bombs, Improvised Explosive Devices, or IEDs, are being used in fighting in Iraq and Afghanistan, creating a growing number of blast injuries. Doctors have noticed that the blast reflect off hard surfaces and multiplies so that people who appear to be protected inside an enclosed space like a Humvee often suffer much worse brain injuries than those outside. Military and civilian researchers began focusing their work on More on page 44