Football: Even “minor” hits can cause brain damage

Today the Amer­i­can Acad­e­my of Neu­rol­o­gy (AAN) “is call­ing for any ath­lete who is sus­pect­ed of hav­ing a con­cus­sion to be removed from play until the ath­lete is eval­u­at­ed by a physi­cian with train­ing in the eval­u­a­tion and man­age­ment of sports concussion.”

At the same time, an arti­cle in Sports Illus­trat­ed reports a new study in which Pur­due researchers put sen­sors (accelerom­e­ters) in the hel­mets of 23 seniors from Jef­fer­son High in Lafayette, Ind. Results are sur­pris­ing and con­cern­ing: Hits that do not even lead to con­cus­sions can have a much big­ger impact on the brain than we thought.

What are concussions?

Con­cus­sions (or mild trau­mat­ic brain injury) are the most com­mon type of trau­mat­ic brain injury. They involve a head injury with a tem­po­rary loss of brain function.

The brain is sur­round­ed by cere­brospinal flu­id, one of the func­tions of which is to pro­tect it from trau­ma. How­ev­er this cush­ion is not always enough in sit­u­a­tions involv­ing severe impacts or mere­ly the forces asso­ci­at­ed with rapid acceleration.

The most com­mon symp­tom of con­cus­sions is headache. Oth­er symp­toms include dizzi­ness, nau­sea, lack of motor coor­di­na­tion, dif­fi­cul­ty bal­anc­ing, visu­al symp­toms, and ring­ing in the ears.

Con­cus­sions can cause a vari­ety of phys­i­cal, cog­ni­tive, and emo­tion­al symp­toms. Symp­toms usu­al­ly go away with­in a few weeks, with­out treat­ment. How­ev­er they may per­sist, or com­pli­ca­tions (such as demen­tia) may occur. No spe­cif­ic treat­ment exists.

Foot­ball and concussions

Some sports such as foot­ball are par­tic­u­lar­ly vio­lent and many play­ers do suf­fer con­cus­sions. This prob­lem is well-known at the Nation­al Foot­ball League (NFL). In July the NFL dis­trib­uted a new poster to teams that warns of the dan­gers from con­cus­sions in much explic­it and harsh­er lan­guage than the league had pre­vi­ous­ly used.

The NFL also man­dates that a play­er suf­fer­ing from a con­cus­sion should stop play­ing if after a hit he can’t car­ry on a coher­ent con­ver­sa­tion or remem­ber the last play …

The new study

What about hits to the brain that do not lead to concussions?

The Pur­due study report­ed in Sports Illus­trat­ed this week and to be pub­lished soon in Jour­nal of Neu­ro­trau­ma in part answers this ques­tion. The 23 young play­ers who par­tic­i­pat­ed in the  study took both the ImPACT test (a com­put­er­ized test assess­ing mem­o­ry and con­cen­tra­tion skills) and tests of work­ing mem­o­ry while their brains were  scanned using func­tion­al MRI.  Work­ing mem­o­ry is the abil­i­ty that allows us to hold infor­ma­tion cur­rent in our mind for the task at hand.

Eleven out of 23 of the play­ers were test­ed again at mid­sea­son. Only 3 had suf­fered con­cus­sions. Of the 8 who had not suf­fered con­cus­sions, 4 nonethe­less showed signi?cant impair­ment in visu­al mem­o­ry. In terms of brain activ­i­ty these 4 play­ers showed a decline in the activ­i­ty of the dor­so­lat­er­al pre­frontal cor­tex (just behind the fore­head) dur­ing the visu­al mem­o­ry task.

The play­ers whose visu­al mem­o­ry was the most impaired “were not com­ing from the con­cussed group but from a group that in the week pre­ced­ing the test had tak­en a large num­bers of hits—around 150—mostly in the 40 to 80 G range.”

The good news is that after 9 months off from foot­ball, the impaired play­ers returned to their base­line scores in the Impact test.


The new Pur­due find­ings sug­gest that even hits not lead­ing to con­cus­sions can affect the brain. Although the results come from a very small num­ber of play­ers and will have to be repli­cat­ed, they are quite concerning.

The study involved young high-school play­ers whose brain is not mature yet. Their brain is thus still very plas­tic and seem to recov­er quick­ly, after a few month with­out foot­ball. But what about old­er play­ers’ brains that may have less abil­i­ty to com­pen­sate for blows?

Pre­vi­ous stud­ies have linked repeat­ed con­cus­sion to Mild Cog­ni­tive Impair­ment (MCI) and demen­tia. For instance, Guskiewicz et al (2005) have found that retired pro­fes­sion­al play­ers (aver­age age of 53.8 years and an aver­age foot­ball career of 6.6 years) with three or more report­ed con­cus­sions have a five­fold preva­lence of MCI diag­no­sis com­pared with retirees with­out a his­to­ry of con­cus­sion. Retirees also an ear­li­er onset of Alzheimer’s dis­ease com­pared to the gen­er­al Amer­i­can male population.

The effects of con­cus­sions, though usu­al­ly short last­ing a the time of the blow,  thus have long-term con­se­quences. What about the long-term effects of those oth­er vio­lent hits that do not lead to con­cus­sions? Future research will tell.

Head injury is list­ed by the Alzheimer’s Asso­ci­a­tion as one of the risk fac­tors for the dis­ease that we can influ­ence. If play­ing foot­ball (or any oth­er vio­lent sport) has to be part of one’s life, aware­ness of the poten­tial dan­gers and look­ing for alter­na­tives strate­gies (sure­ly cel­e­bra­to­ry hel­met-knocks can be avoid­ed?) seem worth a try!


  1. trijicon on November 4, 2010 at 9:26

    Some very inter­est­ing information!!

    I am very glad that the NFL has tak­en a firm stance and tack­led (no pun intend­ed) this issue head on (again no pun intended).

    It real­ly is a shame to see for­mer ath­letes in such ter­ri­ble men­tal con­di­tion after they stop playing…

  2. Christina Acton on November 13, 2010 at 7:17

    Could­n’t agree more with Tri­ji­con… The NFL is tak­ing a stance on these types of hits and they should. The play­ers need to be pro­tect­ed! How­ev­er, it can be quite sad to see the for­mer ath­letes and the lack of sup­port they are get­ting from the NFL. Unfor­tu­nate­ly, that is why we might see a strike next year.

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SHARPBRAINS es un think-tank y consultoría independiente proporcionando servicios para la neurociencia aplicada, salud, liderazgo e innovación.

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