A new study using data from the National Collegiate Athletic Association (NCAA) Injury Surveillance Program (ISP) provides some insight into the epidemiology of SRC outcomes in 25 collegiate sports.
A total of 1670 concussions were reported during the 2009-2010 and 2013-2014 academic years. Of these, an average of 5.29 concussion 
symptoms were reported, with the most common being headache (92.2%) and dizziness (68.9%). Most concussions had symptoms resolve within 1 week (60.1%), however, 6.2% had symptoms resolve in over 4 weeks. In addition, 8.9% of concussions required over 4 weeks before return to play. The proportion of SRCs that required at least 1 week before return to play increased from 42.7% in 2009-2010 to 70.2% in 2013-2014.
The average number of symptoms and resolution time for concussion symptoms did not differ by sex. However, the types of symptoms experienced were different. A larger proportion of concussions in male athletes included amnesia and disorientation, while a larger proportion of concussions in female athletes included headache, excess drowsiness, and nausea/vomiting.
A total of 151 SRCs (9.0%) were reported as recurrent. The average number of symptoms reported with recurrent SRCs (5.99 ± 3.43) was greater than that of nonrecurrent SRCs (5.22 ± 2.88; P = .01). A greater proportion of recurrent SRCs also resulted in a long symptom resolution time (14.6% vs 5.4%, respectively; P < .001) and long return-to-play time (21.2% vs 7.7%, respectively; P < .001) compared with nonrecurrent SRCs.
Source: American Journal of Sports Medicine, published online November 6, 2015
