Brain injury and heading in soccer

BMJ 2003; 327 doi: http://dx.doi.org/10.1136/bmj.327.7411.351 (Published 14 August 2003)
Cite this as: BMJ 2003;327:351

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McCrory’s timely leader (BMJ 16th August 2003) reflects current interest in the field of head injury in sport and in particular whether a career in football involving heading the ball leads to problems in later life.

We are in agreement with McCrory’s conclusion namely that critical review of existing studies does not support the view that football activity, including heading, leads to later physical or cognitive deficits. However some cross sectional studies of selected soccer players suggest some degree of neuropsychological impairment but the causal mechanism in these studies is at best debatable and the range of factors that may be operative such as concussive events, alcohol, drugs, family history have not been disentangled or assessed.

We differ from McCrory however when he states that “ prospective controlled studies using clinical examination, neuro-imaging or neuropsychological testing have failed to find any evidence of cognitive impairment.” The three studies cited by McCrory are not prospective in the sense of clinically realistic, valid test re-test intervals nor do they employ detailed neuropsychological testing. Currently, in fact, there is no published data from longitudinal prospective studies.

Our own research group in 2002 completed baseline data collection including full clinical history and neurological assessment, M.R.I. high definition scanning and detailed neuropsychological profile on 32 young U.K. professional footballers as part of a Professional Footballers Association/Football Association funded study. A cohort of matched controls has been recruited. This is a 10 year prospective study with data collection at baseline, 5 years and 10 years respectively.

The authors await the findings with interest and although it will be some years before the final report is available we believe it promises to be a focused and definitive contribution to this debate.

Competing interests: None declared

Competing interests: None declared

R. Myles Gibson, Neurological surgeon

Steve Kemp, Alastair Duff, Michael Nelson

Neurosciences department, The General Infirmary at Leeds, LS2 9NZ

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A medical paper about head injury in soccer, without manifestation of a Brazilian neurologist, certainly is incomplete...As many people know, soccer is the most played sport in my country, some kind of a religion, with millions of Brazilian citizens acting as amateur players, coachers, commentarists; they have heavy criticism to all aspects of the sport, from schemes and tactics of the game per se to corruption of the directors of teams and leagues. As a journalist and writer of the 50’s wrote,” Brazil is the country with ‘chuteiras’”, the heavy and often dangerous sport shoe with pins.

That is nothing new in one aspect: the comparison with soccer players with boxers. This kind of activity – I refuse myself to consider boxing a sport – leads to micobleedings,lacunes,etc.,and is a fact the “boxer dementia”, the “Parkinson’s” of the boxers,etc.

However, the paper illustrates very well things we can observe every day in emergency services, in soccer camps and also playing only as diversion: head to ball contacts is common, and in this large country of millions of soccer players, I never see a ball contact cause any neurological alterations, acute or chronic. And when I wrote millions of people I are using correct words, approximations, but Brazilians plays soccer every day, in small car parking places to semi-professional or professional gyms. We don1t have an evidence-based study, but the day-by- day observation speaks for itself.

On the other hand, head to head traumas are another thing: I actually attended personally more than 100 cases in twenty years of neurology, and the most common clinical picture is loss of counciencness, with normal image examinations and no sequels. But neurologist and neurosurgeons here certainly have cases in their files with skull fractures, bleeding hematomas, brainstem lesions and a sort of other clinical or surgical problems.

When such a case is presented in a professional team and/or in a knower player, the head to head events riches the media. But the most common occurs in amateur playing, with unnoted players for the people – they are first assisted by paramedics or fire department rescue teams, reach an ER and, even in the complicated cases, nobody pay much attention to that – I am talking about the press, not the medical assistance.

Looking as a Brazilian – I like soccer, but I don’t play the sport – with an enormous number of people playing this sport at all moments, every day (and night),I agree with the fact that the ball injury has almost nothing in regard to brain lesions, but the head to head, without doubts, is an important point to be considered. And I also agree with the usefulness of helmets or something like that – certainly these things cannot help the player (and even the game), but is an attitude typical from north-Americans: the industrial field of such types of equipment could be very happy if these thing turning an obligatory item.

Competing interests: None declared

Competing interests: None declared

CELIO LEVYMAN,MD,MSc, Neurologist

Neurology and Headache Clinic,Rua Jose Janarelli,199/22,Sao Paulo,SP,Brazil,01124-010

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McCrory’s timely leader (BMJ 16th August 2003) reflects current interest in the field of head injury in sport and in particular whether a career in football involving heading the ball leads to problems in later life.

We are in agreement with McCrory’s conclusion namely that critical review of existing studies does not support the view that football activity, including heading, leads to later physical or cognitive deficits. However some cross sectional studies of selected soccer players suggest some degree of neuropsychological impairment but the causal mechanism in these studies is at best debatable and the range of factors that may be operative such as concussive events, alcohol, drugs, family history have not been disentangled or assessed.

We differ from McCrory however when he states that “ prospective controlled studies using clinical examination, neuro-imaging or neuropsychological testing have failed to find any evidence of cognitive impairment.” The three studies cited by McCrory are not prospective in the sense of clinically realistic, valid test re-test intervals nor do they employ detailed neuropsychological testing. Currently, in fact, there is no published data from longitudinal prospective studies.

Our own research group in 2002 completed baseline data collection including full clinical history and neurological assessment, M.R.I. high definition scanning and detailed neuropsychological profile on 32 young U.K. professional footballers as part of a Professional Footballers Association/Football Association funded study. A cohort of matched controls has been recruited. This is a 10 year prospective study with data collection at baseline, 5 years and 10 years respectively.

The authors await the findings with interest and although it will be some years before the final report is available we believe it promises to be a focused and definitive contribution to this debate.

R. Myles Gibson, Neurological Surgeon
Steve Kemp, Neuropsychologist
Alastair Duff, Neuropsychologist
Michael Nelson, Neuroradiologist

Neurosciences Department – The General Infirmary at Leeds

Ref: McCrory P.R. Brain Injury and Heading in Soccer; BMJ 2003; 351;352;16 August 2003

Competing interests: None declared

Competing interests: None declared

R Myles Gibson, Neurological Surgeon

152 Harley Street, London W1

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being a soccer fan and a former school player, it is better to hear from the horse's mouth. players receive significant sub-concussion during heading the ball. sometimes, when the impact is great, there is transient blurring of vision along with ataxia, albeit for a short period. if the ball lands on the vertex, it is often associated with severe headache. boxers face a similar problem. the case of mohamed ali is well known. parkinson's disease among boxers is a well described entity. from this i can extrapolate that frequent heading of the ball can lead to brain damage. what is needed is a study to confirm this hypothesis.the sporting span of most international players is short and by age forty most have retired from active games. they should be examined then and followed up, as along with aging, the subclinical cognitive impairment described may become obvious.

Competing interests:   None declared

Competing interests: None declared

manan vasenwala, consultant-cardiologist (non-invasive)

k.k.heart center, aligarh-202002.india

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In the article entitled ”Brain injury and heading in soccer”, in the August 16th BMJ, Mr. McCrory states that “heading a soccer ball results in head accelerations of less than 10g (or less than 1000 rad/s2) whereas the minimum values for the development of sports related concussions are 40-60 g (or 3500-5000 rad/s2)” with a reference to an article published by our group. First, it is not appropriate to mix or equate linear acceleration measured in g (1 g=9.8m/s2) with angular acceleration measured in rad/s2. Also, although several of our earlier studies indicated linear accelerations near 10 g during soccer heading, our most recent studies at higher speeds (12m/s or 26 mi/hr) have shown average linear accelerations of more than 20 g and average angular accelerations of 1500 rad/s2 for direct frontal impacts. (1) Soccer ball speeds significantly higher than 12 m/sec ( 26 mph) are reached on the soccer field, with speeds up to 80 mph reported. At these speeds, the linear acceleration and angular accelerations would be higher with greater potential for injury.

We do not believe the minimum values of acceleration at which concussion occurs are known. In any head injury, the linear acceleration and angular acceleration of the skull may combine to cause brain injury. Angular acceleration is hypothesized to be more important because the brain is more susceptible to the ensuing shear deformation. In the original experiments by Gennarelli (2) it was reported that monkeys that were immobilized by cervical collars were much less likely to receive concussions than animals whose heads were allowed to rotate. This leads us to speculate that factors that affect angular acceleration (head position, angle of heading, location of impact) will affect the potential for injury. Perhaps the most important predictor of concussion is a history of prior concussion. A person who has had one concussion is three times more likely to have a second, and eight times more likely to have a third concussion than a member of the general population. (3) This cumulative effect may be present at sub-concussive levels as well. For this reason, we do not believe the cumulative effects of soccer heading are fully known.

Naunheim RS, Bayly PV, Standeven J, Neubauer JS, Lewis LM, Genin GM. Linear and Angular Head Accelerations during Heading of a Soccer Ball. Medicine & Science in Sports & Exercise, 35:1406-1412, 2003.

Gennarelli TA. Head injury in man and experimental animals: clinical aspect. Acta Neurochir. Suppl. 32:1-13, 1983.

Annegers JF. The incidence, causes and secular trends of head trauma in Olmstead County, MN, 1935-1974. Neurology 30:912-919, 1980.

Sincerely,

Rosanne S. Naunheim, MD, Philip Bayly, PhD, Guy Genin, PhD, Larry Lewis, MD, John Standeven, PhD. Washington University School of Medicine Washington University School of School of Engineering 660 So. Euclid, Box 8072 St. Louis, MO 63110

Competing interests:   None declared

Competing interests: None declared

Rosanne S Naunheim, Associate Prof. of Emer. Med

Philip Bayly, Guy Genin, Larry Lewis, John Standeven

Washington University School of Medicine, 600 So Euclid, Box 8072, St. Louis, MO 63110

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Dr. McCrory's editorial nicely summarizes the state of knowledge relating to concussion and soccer (football). I agree with most of Dr. McCrory's points but would like to raise some questions that could be addressed in future research. I don't think it is yet possible to say that recurrent concussion due to head to head or other non-ball impacts, as opposed to routine ball heading, is the major source of concern. Nor is it really possible to say that recurrent head to head or other non-ball impacts have little or no cumulative sequelae. My impression, like Dr. McCrory's, is that routine ball heading is not a major concern and that concussions lack cumulative sequelae but answering these related questions requires a substantial prospective study in which both ball heading and concussion effects were assessed with robust and relevant outcome measures. All studies to date are small or retrospective. I disagree with the statement that head to head concussive events or similar events are infrequent. My experience as a player, coach, and parent has been that concussive events are relatively common. These events include not only head to head impacts but also kicks in the head, head to ground impacts, and perhaps most worrisome, head to goalpost impacts. My sons' high school team averages about 3 signficant concussive events per season and my impression, based on several years of youth coaching, is that this is not unusual. I agree with Dr. McCrory's suggestion that better coaching would improve safey but I think that there are some additional and perhaps simpler interventions that might improve safety. A very simple intervention would be goalpost padding. While goalpost impacts are uncommon, they can be particularly dangerous. A study assessing benefits of goal post padding would be relatively easy to conduct. Another potentially useful intervention would be encouraging a rigorous standard of officiating, particularly with respect to free kicks near the goal and corner kicks, where there is not only a lot of physical play but also an increased likelihood of head to head impacts.

Competing interests:   None declared

Competing interests: None declared

Roger L. Albin, Professor of Neurology

University of Michigan

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