According to neurologist and boxing physician Anthony Alessi, when blood supply to the brain is not sufficient to repair the level of damage, the fighter will lose consciousness. D said. And eventually they are unable to defend themselves. Not surprisingly, studies show that around 90 per cent of professional boxers will endure some form of brain injury throughout the course of their career, while numerous researchers have found that between per cent of boxers showed signs of chronic brain injury.
This culminated in approximately boxing-related deaths in the period from to , with 66 per cent of these being attributed to head and neck trauma. Despite a major development in concussion protocols and management in recent years, death in combat sports is still a very shocking reality. In alone, three professional boxers were killed by knockout punches they received during scheduled fights. Phindile Mwelase of South Africa, Oscar Gonzalez of Mexico and Japanese fighter Tesshin Okada all passed away having never regained consciousness after being knocked out.
Earlier this year, Australian professional boxer Braydon Smith died after collapsing following a welterweight bout in Toowoomba, Queensland. The year-old suffered severe swelling on the brain as a result of injuries suffered during the bout. Here, the polar head groups face the edge of the pore which prevents the pore from immediately collapsing.
The crowding of the fatty acid tails at the edges does, however, causes instability and will, within minutes, lead to the closure of the pore. It can be argued that once a pore has been formed, the kinetics of resealing should be independent of the nature of the forces that lead to its creation.
If this is true then porated neurons in a knocked-out boxer would be resealed within minutes, leading to the return of consciousness. Thus, the timeframe for both the formation and the spontaneous closure of the pores are a good match for the observed symptoms.
The experimental evidence for mechanoporation is, however, so far indirect and relies on influx of marker substances in animal models and in silico modeling. More direct evidence, such as visualization of actual pores, is still not available and more work remains before mechanoporation can be considered fully verified. It may be that seeing a person being knocked out, and then rapidly regaining consciousness, is so common that it is taken for granted. But from the above description, it should be clear that this sequence of events is difficult to explain on a cellular and molecular level.
Compared with concussion in general, the patient characteristic and mechanical forces in the boxing knockout are very homogeneous and may therefore serve as a suitable starting point.
Admittedly, the timescale of the primary injury precludes any medical intervention and future therapeutics would therefore have to target secondary injury processes. A fully verified and detailed description of the primary injury in boxing knockouts, and concussion in general, would be very useful though.
It could potentially make it possible to define a safe level of mechanical strain on brain tissue, which would aid in the design of protective equipment and the regulation of sports. An increased understanding of the pathophysiological mechanism would also increase the chances of finding better treatments for patients with postconcussive syndrome, chronic traumatic encephalopathy, and diffuse axonal injury.
And perhaps a better understanding of how consciousness is lost may be a first step toward understanding consciousness itself. AH drafted the original manuscript. ER contributed novel ideas, insights, and knowledge to the final manuscript. Both authors contributed to the article and approved the submitted version. The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.
Thanks to professor Per Enblad for valuable comments on this manuscript and to Tim Howells for careful proofreading. National Center for Biotechnology Information , U.
Journal List Front Neurol v. Front Neurol. Published online Oct Author information Article notes Copyright and License information Disclaimer. Reviewed by: David F. Giglio, Italy. This article was submitted to Neurotrauma, a section of the journal Frontiers in Neurology.
Received Jun 8; Accepted Sep The use, distribution or reproduction in other forums is permitted, provided the original author s and the copyright owner s are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. Abstract Several hypotheses have been put forth over time to explain how consciousness can be so rapidly lost, and then spontaneously regained, following mechanical head trauma.
Keywords: traumatic brain injury, concussion, boxing, mechanoporation, mechanosensitive MS ion channel. A History of Knockouts The proportions of the human hand differ from other primates, which tend to have longer fingers.
Symptoms of a Punch A strike to the head which does not lead to unconsciousness may still induce a state characterized by reduced reaction speed and confusion. The Biomechanics of a Knockout For a punch to damage the brain, the force from the impact must somehow be transferred through the skull and into the brain tissue.
Open in a separate window. Figure 1. The Convulsive Hypothesis According to this hypothesis, the mechanical forces of the impact trigger a depolarization of the neuronal cell membrane, which leads to uncontrolled release of action potentials. Vascular Hypotheses When a knockout is fatal, a CT scan typically reveals extensive cerebral hemorrhage, which makes it reasonable to assume that tearing of blood vessels is the main form of primary injury in this case. Microtubule Breakage Normal body movements lead to stretching of axons in the peripheral nervous system which can readily adjust their length without damage in this case Mechanosensitive Ion Channels Mechanosensitive ion channels are found in several parts of the body, for example, the heart, urine bladder, and inner ear, where they are required for normal physiology.
The Mechanoporation Hypothesis Pore formation in a cell membrane induced by mechanical forces is referred to as mechanoporation, which primarily has been investigated by using molecular markers to evaluate cell membrane permeability following experimental brain trauma 28 , Figure 2. Benefits of Understanding Knockouts It may be that seeing a person being knocked out, and then rapidly regaining consciousness, is so common that it is taken for granted.
Author Contributions AH drafted the original manuscript. Conflict of Interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest. Acknowledgments Thanks to professor Per Enblad for valuable comments on this manuscript and to Tim Howells for careful proofreading. Footnotes Funding. References 1. Protective buttressing of the human fist and the evolution of hominin hands.
J Exp Biol. Concussion: the history of clinical and pathophysiological concepts and misconceptions. Concussion is confusing us all. Pract Neurol. Martland HS. Punch drunk. Experimental concussion. Proc R Soc Med. Cournoyer J, Hoshizaki TB. Head dynamic response and brain tissue deformation for boxing punches with and without loss of consciousness. Clin Biomech. N Engl J Med. The relation between loss of consciousness, severity of traumatic brain injury, and injury of ascending reticular activating system in patients with traumatic brain injury.
Am J Phys Med Rehabil. Impaired consciousness due to injury of ascending reticular activating system. Transl Neurosci. Cerebral concussion and traumatic unconsciousness. Correlation of experimental and clinical observations of blunt head injuries. The physiological basis of concussion. J Neurosurg. Shaw NA. The neurophysiology of concussion. Prog Neurobiol. Hosseini AH, Lifshitz J.
Brain injury forces of moderate magnitude elicit the fencing response. Med Sci Sports Exerc. Concussive convulsions: incidence in sport and treatment recommendations. Sports Med. Concussive convulsions: a YouTube video analysis. Submit a Question. Engage local scientists to educate your community about the brain. Do you believe any of these common neuromyths? Test your knowledge. Read More. For Educators Log in.
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