Table 1

 Descriptive statistics for the test scores by group

Variable/groupMedianMeanSDIQR10th centile90th centile
None, No previous concussions (n  =  664); One, one previous concussion (n  =  149); Two, two previous concussions (n  =  54).
IQR, Interquartile range.
*Reaction time is in seconds; faster (lower numbers) is better. This is reflected in the IQR and the 10th and 90th centiles.
Verbal memory
Visual memory
Processing speed
Reaction time*
Total symptoms