Immediately following a concussion, signs and symptoms will vary greatly from one individual to another. Age, gender, number of past concussions, time since last concussion and even certain genetic predispositions are all factors that influence how the concussion will clinically manifest and evolve.
Approximately one out of five people will only start experiencing symptoms 24 to 48 hours after the initial incident. As for athletes, studies show that one in two will hide symptoms in order to avoid being removed from play. This highlights the importance of removing an athlete for play immediately after a concussion is suspected.
Up to 20 different signs and symptoms have been reported in the hours and days following a concussion. However, 10 of them are more commonly reported (see Table 1).
Source : Guskiewicz et al. (2000); Castile et al. (2012)
Symptoms are undoubtedly an important source of information when it comes to understanding the condition and recovery of the athlete. However, because the clinical picture and its evolution vary greatly from athlete to athlete, no particular symptom can be used to accurately predict the evolution of the concussion and recovery. Hence, signs and symptoms cannot be relied upon as good indicators. For this reason, international concussion experts recommend that an athlete be removed from play immediately if he/she is suspected of having sustained a concussion.