I’ve talked before about how even mild head injuries can have serious consequences, and in recent years we’ve seen growing awareness of the long-term dangers of sports’ concussions (especially for young people). This has been followed by a number of initiatives to help protect athletes. However, while encouraging, they may still be under-estimating the problem. Two recent studies, involving high school athletes who had experienced concussions, point to quite subtle impairment lasting for longer than expected.
In one study, 20 concussed adolescents were tested on their attention and executive function within 72 hours post injury, and then again at one week, two weeks, one month, and two months post injury. Compared with matched controls, they had a significantly greater switch cost on the Task-Switching Test and a significantly greater reaction time for the Attentional Network Test conflict effect component, with this lasting up to two months after injury.
The results suggest that longer recovery periods than the standard 7-10 days may be warranted, given that the slower reaction times (although only a matter of milliseconds) might make further injury more likely.
In another study, 54 adolescent athletes who had been concussed but who reported being symptom-free and had returned to baseline neurocognitive-test levels, were given, further testing. This revealed that over a quarter of them (27.7%) showed cognitive impairment following moderate physical exertion (15 to 25 minutes on a treadmill, elliptical, or stationary bicycle). These athletes scored significantly lower on verbal and visual memory, although processing speed and reaction was not affected (suggesting that tests focusing mainly on these latter abilities are insufficient).
The group affected did not differ from the rest in terms of symptoms or concussion history.
The findings suggest that computerized neurocognitive testing following moderate exertion should be part of the standard procedure when making return-to-play decisions.
 . Effects of Concussion on Attention and Executive Function in Adolescents. Medicine & Science in Sports & Exercise [Internet]. 2012 . Available from: http://journals.lww.com/acsm-msse/Abstract/publishahead/Effects_of_Concussion_on_Attention_and_Executive.98473.aspx
 . Post-exertion neurocognitive test failure among student-athletes following concussion. Brain Injury [Internet]. 2013 ;27(1):103 - 113. Available from: http://informahealthcare.com/doi/abs/10.3109/02699052.2012.729282?prevSearch=allfield%253A%2528McGrath%2529&searchHistoryKey=&