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 sig­nifi­cant 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.

Con­clu­sions

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!

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