No cumulative effects for one or two prior concussions

British Journal of Sports Medicine. 2004 Oct;


Iverson, G. L., R. T. Lange, M. R. Lovell and M. W. Collins.



Introduction: Sports medicine clinicians and the general public are interested in the possible cumulative effects of concussion. The purpose of this study was to examine whether athletes with a history of one or two previous concussions differed oil their preseason neuropsychological test performance or symptom reporting. Method: Participants were 867 male high school and university amateur athletes who completed preseason testing with ImPACT Version 2.0. Their average age was 17.7 years (SD = 2.3) and their average education was 11.3 years (SD = 2.0). The breakdown of athletes by sport was as follows: American Football = 86.7%, Ice Hockey = 9.6%, Soccer = 2.3%, and other sports = 1.4%. Participants were sorted into three groups on the basis of number of previous concussions. There were 664 athletes with no previous concussions, 149 with one concussion, and 54 with two past concussions. Results: One-way analysis of variance was conducted using ImPACT Version 2.0 Verbal Memory, Visual Memory, Reaction Time, Processing Speed, and Postconcussion Symptom composite scores as dependent variables and group membership as the independent variable. There were no significant main effects for group. The group with two previous concussions was slightly older than the other two groups. Exploratory pairwise comparisons using t-tests uncorrected for familywise error also did not yield any significant effects attributable to concussion history. Discussion: There was no measurable effect of one or two previous concussions on athletes’ preseason neuropsychological test performance or symptom reporting. If there is a cumulative effect of one or two previous concussions, it is very small and undetectable using this methodology.

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