Objective: The purpose of this study was to examine, using a dose-response model, sex differences in computerised neurocognitive performance among athletes with a history of multiple concussions.
Design: Retrospective with randomly selected concussion cases from four levels/numbers of previous concussion.
Setting: Multicentre analysis of NCAA student-athletes.
Participants: Subjects included a total of 100 male and 88 female NCAA athletes.
Intervention: Sex and four mutually exclusive groups of self-reported concussion history: (1) no history of concussion, (2) one previous concussion, (3) two previous concussions, (4) three or more previous concussions.
Main outcome measurements: Neurocognitive performance as measured by a computerised neurocognitive test battery (Immediate Postconcussion Assessment Cognitive Testing (ImPACT)).
Results: A dose-response gradient was found for two or more previous concussions and decreased neurocognitive performance. Females with a history of two and three or more concussions performed better than males with a history of two (p=0.001) and three or more concussions (p=0.012) on verbal memory. Females performed better than males with a history of three or more concussions (p=0.021) on visual memory. Finally, there was a significant difference for sex on both motor processing speed and reaction-time composite scores. Specifically, males performed worse than females on both processing speed (p=0.029) and reaction time (p=0.04).
Conclusion: The current study provided partial support for a dose-response model of concussion and neurocognitive performance decrements beginning at two or more previous concussions. Sex differences should be considered when examining the effects of concussion history on computerised neurocognitive performance.