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
    None87.987.18.382.0–93.476.097.2
    One87.087.17.682.3–93.476.997.2
    Two86.186.17.381.3–91.876.695.1
Visual memory
    None78.077.311.869.4–86.161.192.0
    One77.877.011.570.4–84.761.092.0
    Two76.476.411.470.6–83.359.091.3
Processing speed
    None36.436.66.832.4–40.728.345.4
    One37.837.26.832.0–41.528.246.4
    Two38.736.86.631.8–41.327.644.6
Reaction time*
    None0.5500.5590.0750.600–0.5100.6500.480
    One0.5500.5570.0680.600–0.5100.6400.480
    Two0.5500.5630.0680.583–0.5200.6450.485
Total symptoms
    None2.04.97.90–6014
    One2.05.38.70–6019
    Two2.05.78.50–9018