Individual and Combined Effects of Sport-Related Concussion and Anterior Cruciate Ligament Injury on Neurocognitive and Neuromechanical Reaction Time.

CONTEXT: Recent epidemiological data have indicated a potential connection between sport-related concussion (SRC) and elevated anterior cruciate ligament (ACL) injury risk. Limited research exists in which authors have quantified cognitive and motor outcome measures between SRC and ACL injury history.

OBJECTIVE

To examine the individual and combined effects of a history of SRC and ACL injury and reconstruction (ACLR) on neurocognitive and neuromechanical function.

DESIGN

Cross-sectional study.

SETTING

Research laboratory.

PATIENTS OR OTHER

PARTICIPANTS

Forty-seven recreationally active college individuals with either an injury history of SRC (n = 12), ACLR (n = 12), combination of SRC + ACLR (n = 11), or uninjured controls (n = 12).

MAIN OUTCOME MEASURE(S): Participants completed a neurological battery using the C3 Logix application and TRAZER system for neuromechanical reaction time (RT). C3 Logix subtests consisted of the Trail Making Test (TMT) A, B, and B - A; simple and choice RT; and processing speed. TRAZER subtests consisted of simple, Flanker-task, and Stroop-task RT. Participants were categorized into 3 group comparisons of either (i) SRC, ACLR, SRC + ACLR, and controls, (ii) any or no SRC overall, or (iii) any or no ACLR overall.

RESULTS

No differences were demonstrated between SRC, ACLR, SRC + ACLR, and controls on TMT (P = .07-.14), neurocognitive (P = .14-.93), or neuromechanical (P = .64-.99) performance. Those with any SRC had slower TMT B - A times (P = .03), while those with any ACLR had slower TMT A (P = .02) times than those with no ACLR. No differences were noted for the TRAZER simple, Flanker, or Stroop RT for any or no SRC and ACLR groups.

CONCLUSIONS

College students with a combined effect of SRC and ACLR did not differ from other groups on neurocognition and neuromechanical RT. Individuals with a history of SRC or ACLR had a worse TMT, leading to inquiry about potential long-term neurological deficits, despite no differences in those with a combined history.