Con­cus­sion is de­fined as a com­plex patho­phys­i­o­log­i­cal process af­fect­ing the brain, in­duced by trau­mat­ic bio­me­chan­i­cal forces. This leads to rapid on­set of func­tion­al (not struc­tur­al) neu­ro­log­i­cal im­pair­ment. In re­al­i­ty, this means a com­pli­cat­ed head in­jury, which im­me­di­ate­ly af­fects brain func­tion but may not phys­i­cal­ly dam­age the brain. It may or may not be ac­com­pa­nied by loss of con­scious­ness.

The ac­tu­al in­jury is not some­thing that just shows up on an MRI scan like a frac­ture would on an x-ray. It doesn’t have tell-tale signs that doc­tors or phys­io­ther­a­pists can use to iden­ti­fy and con­firm the di­ag­no­sis. Rather, it can be some­thing as sub­tle as a change in per­sona. Al­so, it may not be­come ev­i­dent un­til 24 to 48 hours lat­er. So, there is a need to keep close mon­i­tor­ing of any­one who gets a hit on the head.

Con­cus­sion in­juries have re­ceived a lot of at­ten­tion in box­ing, Amer­i­can foot­ball and rug­by—sports with heavy con­tact. Play­ers in these sports were ex­pect­ed to “man up” to head in­juries. But it has now be­come ap­par­ent that it is not just the short term ef­fects that make the con­di­tion wor­ry­ing, but that cu­mu­la­tive ef­fects of re­peat­ed in­juries and im­prop­er im­me­di­ate man­age­ment have long term ef­fects. So dev­as­tat­ing are the long-term ef­fects, with chron­ic brain im­pair­ment and sug­ges­tion of links with Parkin­son, that a class-ac­tion suit by Na­tion­al Foot­ball League (NFL) play­ers has led to ma­jor at­ten­tion be­ing paid to con­cus­sion in sport. Rug­by be­came very proac­tive, man­dat­ing that each team had a doc­tor and that a doc­tor could man­date re­moval of a play­er with a sus­pect­ed con­cus­sion in­jury. Team doc­tors came un­der such pres­sure from coach­es and team mem­bers that it was felt that their judge­ment may be af­fect­ed. Hence, they now have in­de­pen­dent match day doc­tors who make the call. This is sim­i­lar in the NFL and box­ing.

At the oth­er end of the spec­trum was the FI­FA World Cup where there were re­peat­ed in­stances of ob­vi­ous con­cus­sions, in which the play­ers de­fied the team doc­tor’s or­ders and re­mained in play, of­ten sup­port­ed by the coach­es. There has been pub­lic chas­tise­ment of an Eng­lish Pre­mier League club’s doc­tor when she right­ly re­moved a con­cussed play­er and the coach not on­ly den­i­grat­ed her but tried to have her dis­missed as well. Were it not for Sports Physi­cians all over the world back­ing her de­ci­sion, she would have suf­fered per­ma­nent rep­u­ta­tion­al dam­age.

One of the prob­lems is that the signs and symp­toms of con­cus­sion can be very sub­tle. Of­ten, it presents with dizzi­ness, woozi­ness, hazi­ness in front of the eyes, or slight lethar­gy, or in­abil­i­ty to make quick de­ci­sions. The play­er may not feel this till the next day, as was ev­i­dent in the two in­stances that took place in test crick­et since the in­tro­duc­tion of con­cus­sion re­place­ments in the game. Steve Smith of Aus­tralia and Daren Bra­vo of the West In­dies were both re­placed af­ter their in­juries when the symp­toms be­came ap­par­ent. In each case, there was a vis­i­ble head in­jury, af­ter which the play­er ap­peared un­af­fect­ed. Yet, by the next day, they had to be re­placed. One can on­ly imag­ine how many sim­i­lar in­stances had tak­en place in the past, with the play­ers con­tin­u­ing to play to the detri­ment of their short and long term health and per­for­mance.

Con­cus­sion is of­ten neb­u­lous and re­quires man­age­ment by ex­perts. This is guid­ed by a Con­sen­sus State­ment on Con­cus­sion. The last ma­jor one was pub­lished af­ter the Berlin Con­ven­tion in 2016 and is re­vised fre­quent­ly. A main fea­ture of the man­age­ment is hav­ing a base­line on each ath­lete so that sub­tle changes can be matched against the ath­lete’s per­son­al “nor­mal.” This is done by ad­min­is­ter­ing the Sport Con­cus­sion As­sess­ment Test at the start of the sea­son and many times af­ter the in­jury un­til the re­sults match the base­line. This SCAT 5 test is read­i­ly avail­able on­line.

Use of tech­nol­o­gy has al­so been ad­vo­cat­ed. A Con­sen­sus State­ment on Video Signs of Con­cus­sion was pub­lished in Oc­to­ber 2019, high­light­ing that field-side ob­ser­va­tion of con­cussed play­ers may not be enough and that video re­view can be use­ful. Ly­ing mo­tion­less for more than two sec­onds, un­steadi­ness (mo­tor in­co­or­di­na­tion), stiff­ness of any limb (ton­ic pos­tur­ing), flop­pi­ness, or a blank, va­cant look are all signs on video re­view that can be used to make the di­ag­no­sis.

The man­age­ment of the play­er starts with 24 hours of com­plete rest, fol­lowed by al­low­ing ac­tiv­i­ties of dai­ly liv­ing, light ex­er­cise, sport-spe­cif­ic ex­er­cise, non-con­tact train­ing drills, full prac­tice and a re­turn to com­pe­ti­tion. Each stage has at least 24 hours be­tween them, but longer if the pre­vi­ous stage is not cleared. The SCAT 5 test is per­formed pe­ri­od­i­cal­ly in tan­dem with clin­i­cal ex­am­i­na­tion. In­ves­ti­ga­tions like a CT or MRI Scan are per­formed as in­di­cat­ed.

To date, this has shown to lead to the least long term ef­fects and al­lows the quick­est re­turn to sport. Yet, it re­quires a min­i­mum of six days (and some­times up to many weeks). Hence, it is im­por­tant that the di­ag­no­sis is cor­rect­ly made and that rules like the re­place­ment in crick­et are put in place to pro­tect play­ers.