Does playing soccer cause brain injury?

The skull forms a cavity for the brain and protects it from outside harm. The cerebrospinal fluid surrounds the brain and acts as a shock absorber, preventing damage to the brain when colliding with the skull. If an external force is applied to the head the brain may strike the inside of the skull and may be damaged at the point of impact or by diffuse stretching and tearing.

From punch drunk to dementia pugilistica to chronic traumatic encephalopathy
25 - July - 2009 -- Boxing MatchIt has been known for decades that boxing increases the risk of developing a neurodegenerative disease later in life. The concept of “Punch drunk syndrome” was first coined in 1928 by Harrison Martland, a pathologist and medical examiner from New Jersey. Dr. Martland had noticed an array of symptoms in boxers, exposed to repeated blows to the head. The symptoms were, for example, slowed movement, tremors, confusion and speech problems. In 1937 another American doctor, J.A. Millspaugh put forward the term, dementia pugilistica (meaning the dementia of a fighter, pugil is a boxer in Latin), to describe a syndrome characterized by difficulties in control of movements and mental confusion in boxers. By the 1970s enough boxers suffering from this condition had been studied pathologically to determine the existence of a neurodegenerative disease, similar to, but distinguishable from other neurodegenerative diseases. Since then it has become clear that the neurological deterioration resulting from repeated mild head trauma is not restricted to boxers and the term most frequently used now is chronic traumatic encephalopathy (CTE).

Recent research indicates that CTE may be more common in former contact sports athletes than previously thought. Evidence of CTE has been found, for example, in the brains of athletes participating in contact sports like American football, professional hockey, professional wrestling, and in victims of physical abuse. The condition is characterized by decline in memory and cognition as well as depression, suicidal behavior, poor impulse control, aggressiveness and parkinsonism, that culminates in full-blown dementia. The symptoms of CTE may present themselves years or decades after the end of exposure to repetitive brain trauma, after an athlete has retired from his or her sport, although the neuropathologic changes of CTE have been seen in individuals in their teens and early 20s.

A new study showing changes in the brains of professional soccer players
HEAD ONSoccer is probably the most popular sport in the world and the only sport in which the unprotected head is the primary point of contact when hitting the ball with one’s head (heading). As the harmful effects of repetitive traumatic brain injury (such as damage to the white matter of the brain), are well known in other contact sports, Inga K. Koerte and her colleagues conducted a study comparing the white matter of professional soccer players and swimmers. Only those without history of concussions (self-reported or physician diagnosed) were included in the study. High-resolution diffusion tensor imaging was used to explore structural changes in the brain’s white matter. Their results, published in the Journal of the American Medical Association last month, showed alterations in the white matter of the frontal , temporal and occipital lobes in the soccer players when compared to the swimmers. These regions of the brain are known to be responsible for attention, visual processing, higher order thinking and memory. These results are consistent with studies indicating that soccer players with the highest lifetime estimates of heading, have poorer attention, concentration, cognitive flexibility and general intellectual functioning. The results are also in accord with studies suggesting that the brain can sustain trauma without symptomatic concussion to occur.

Young brains are more susceptible to brain injury
During development, the young brain is different from the adult brain (reached at around 21 years). The rate of development is different between neuronal systems during childhood and brain changes are, at times, dramatic. Areas in the brain involved in sensation and movement are generally developed by the age of 4 and areas for language by the age of 10. The areas involved in abstract processes, reasoning, judgment and emotion remain less developed through the teenage years into the early 20s. The age at the time of head injury may therefore affect the risk of developing CTE later in life. The notion that the plasticity of the young brain may allow it to compensate better for brain injury than the adult brain has not been substantiated. On the contraty, current literature indicates that a younger brain may be more susceptible to brain injury, leading to more pronounced and prolonged cognitive deficits by disrupting normal maturation and development.

Young brains and soccer
Millions of children participate in contact sports such as soccer from an early age. One study comparing sports-related concussion rates across a wide variety of high-school sports, showed that girls’ soccer had the second highest rate of concussion (following American football). We know that repeated mild head trauma, even below the threshold of concussion is a risk factor for structural changes in the brain and repeated head trauma is a risk factor for later development of a neurodegenerative disease. We also know of the damaging impact an early brain trauma can have on the maturing brain. Why then do we not hear louder discussions on the issue of changing the rules of soccer, at least for younger children? Even if the research evidence now gathered are not enough to absolutely prove that heading the ball in soccer is harmful for your current or future cognitive health, as a soccer mom my position is:
Let’s be cautious and err on the safe side while we collect the necessary data. After all, the cognitive health of our children is at stake.

More on the matter:
Understanding the neuroinflammatory response following concussion to develop treatment strategies
A case for mental and physical rest in youth sports concussion: it’s never too late
Concussions Affect Children’s Brains Even After Symptoms Subside
Heads up: Concussion in youth sport
State Concussion Laws Overview

The sobering science of repeat concussions
Concussion crisis growing in girls’ soccer
Soccer, Heading For Trouble?
Youth soccer program BANS heading for players under age of ten over head injury concerns

Built on:

-Corsellis J. A. N., Bruton, C. J. and Freeman-Browne, D. (1973). The aftermath of boxing. Psychological Medicine, 3, 270-303.

-Gavett, B. E., Stern, R. A. og McKee, A. C. (2011). Chronic traumatic encephalopathy: A potential late effect of sport-related concussive and subconcussive head trauma. Clinics in sports medicine, 30(1), 179-188.

-Halldorsson, J., Flekkoy, K. M., Arnkelsson, G. B., Tomasson, K., Gudmundsson, K. R., and Arnarsson, E. O. (2008). The prognostic value of injury severity, location of event, and age at injury in pediatric traumatic head injuries. Journal of Neuropsyciatric disease and treatment, 4(2), 405-412.

-Koerte. I.K., Ertl-Wagner, B., Reiser, M., Zafonte, R., Shenton, M.E. (2012). White matter integrity in the brains of professional soccer players without a symptomatic concussion. JAMA, 308(18), 1859-1861.

-Stern, R. A., Riley, D. O., Daneshvar, D. H., Nowinski, C. J., Cantu, R. C. and McKee, A. C. (2011). Long-term consequences of repetitive brain trauma: Chronic traumatic encephalopathy. PM&R, 3(10, Supplement 2), S460-S467.

-Toledo, E., Lebel, A., Becerra, L., Minster, A., Linnman, C., Maleki, N. et al. (2012). The young brain and concussion: Imaging as a biomarker for diagnosis and prognosis. Neuroscience & Biobehavioral Reviews, 36(6), 1510–1531.

-Witol, A. D. and Webbe, F. M. (2003). Soccer heading frequency predicts neuropsychological deficits. Archives of Clinical Neuropsychology, 18(4), 397-417.

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