A number of reports, which have appeared during the last few years, have shown that the brain is sensitive to blast. This study determines whether the occupational standards for the highest levels of blast exposure were valid enough to avoid brain injuries.
Traumatic brain injury is very common among war veterans from Iraq and Afghanistan and the majority has been exposed to explosions. The soldiers have symptoms of disorders of memory, mental processes, emotion, sleep, speech, vision and hearing. The symptoms may be similar to those of post traumatic stress syndrome, which may be caused by factors other than combat experience.
The brain may be affected by the blast, which is generated during firing of weapons
The Swedish Armed Forces sponsored a study, which has been carried out by scientists at the Sahlgrenska Academy, University of Gothenburg, Sweden. They have examined the effects of noise after the firing of a Haubits, an anti tank weapon (Karl Gustav) and an automatic rifle and by the detonation of plastic explosives underwater. The study was done on anaesthetized pigs and rats.
“We examined the maximal peak level of the blast in the brain transmitted from the blast in the air, as well as, brain tissue changes that were detected with the microscope, says Annette Säljö, one of the scientists who conducted the study.
The noise produced by the firing of both the haubits and the anti-tank weapon exceeds the occupational standards for highest levels of blast exposure. The scientists found that the maximal peak levels of the blast were unexpectedly high in the brain, i.e. that skin and bone appeared to protect the brain poorly. The results suggest that the degree of transmission of a pressure wave from air or water to the brain depends on the dominating frequencies in the frequency spectrum of the noise; low frequencies are transmitted considerably better than high frequencies.
Blast overpressure may result in haemorrhages in the brain
The microscopic examination of the brain showed that the blast from certain weapons produces small haemorrhages (bleeding) in the brain tissue and the meninges (lining of the brain). The examination also suggested that blast exposure leads to the development of brain edema, i.e. increased fluid content. The scientists were later able to support this finding with other measurements. The results are in agreement with findings in the brains of soldiers who had been injured or died after being exposed to explosions in wars, from WW1 to the war in Iraq.
The Swedish Armed Forces have restricted their safety regulations
In summary, the study shows that the maximal peak levels of blast generated by the firing of certain weapons led to a small but measurable effect on the brains of pigs and rats.
The study also showed that this effect on the brain becomes worse with increasing maximal peak blast levels. The results poses the question as to whether exposure to even lower levels of blast than previous thought injurious might be contributing to the large numbers of mild traumatic brain injuries in American military personnel.
“This is of course an occupational question for Swedish Armed Forces. In light of the results of the study, the Swedish military has instituted restrictions in the number of firing rounds a person is allowed to be exposed to in a single day”, says Annette Säljö.
Direct studies on humans are difficult to perform, since biomarkers of injury in cerebrospinal fluid or blood and imaging studies such as computed tomography (CT) and magnetic resonance imaging (MRI) do not appear to be specific or sensitive enough to detect mild brain injury.
Helena Aaberg | alfa
Advanced analysis of brain structure shape may track progression to Alzheimer's disease
26.10.2016 | Massachusetts General Hospital
Indian roadside refuse fires produce toxic rainbow
26.10.2016 | Duke University
Ultrafast lasers have introduced new possibilities in engraving ultrafine structures, and scientists are now also investigating how to use them to etch microstructures into thin glass. There are possible applications in analytics (lab on a chip) and especially in electronics and the consumer sector, where great interest has been shown.
This new method was born of a surprising phenomenon: irradiating glass in a particular way with an ultrafast laser has the effect of making the glass up to a...
Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion
Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
27.10.2016 | Materials Sciences
27.10.2016 | Physics and Astronomy
27.10.2016 | Life Sciences