Clinical Reaction-Time Performance Factors in Healthy Collegiate Athletes

Context: In the absence of baseline testing, normative data may be used to interpret postconcussion scores on the clinical reaction-time test (RTclin). However, to provide normative data, we must understand the performance factors associated with baseline testing. Objective: To explore performance factors associated with baseline RTclin from among candidate variables representing demographics, medical and concussion history, self-reported symptoms, sleep, and sport-related features. Design: Cross-sectional study. Setting: Clinical setting (eg, athletic training room). Patients or Other Participants: A total of 2584 National Collegiate Athletic Association student-athletes (n = 1206 females [47%], 1377 males [53%], and 1 unreported (<0.1%); mass = 76.7 +/- 18.7 kg; height -176.7 +/- 11.3 cm; age =19.0 +/- 1.3 years) from 3 institutions participated in this study as part of the Concussion Assessment, Research and Education Consortium. Main Outcome Measure(s): Potential performance factors were sex; race; ethnicity; dominant hand; sport type; number of prior concussions; presence of anxiety, learning disability, attention-deficit disorder or attention-deficit/hyperactivity disorder, depression, or migraine headache; self-reported sleep the night before the test; mass; height; age; total number of symptoms; and total symptom burden at baseline. The primary study outcome measure was mean baseline RTclin. Results: The overall RTclin was 202.0 +/- 25.0 milliseconds. Female sex (parameter estimate [B] = 8.6 milliseconds, P < .001, Cohen d = 0.54 relative to male sex), black or African American race (B = 5.3 milliseconds, P= .001, Cohen d = 0.08 relative to white race), and limited-contact (B =4.2 milliseconds, P < .001, Cohen d = 0.30 relative to contact) or noncontact (B = 5.9 milliseconds, P < .001, Cohen d = 0.38 relative to contact) sport participation were associated with slower RTclin. Being taller was associated with a faster RTclin, although this association was weak (B = -0.7 milliseconds, P < .001). No other predictors were significant. When adjustments are made for sex and sport type, the following normative data may be considered (mean +/- standard deviation): female, noncontact (211.5 +/- 25.8 milliseconds), limited contact (212.1 +/- 24.3 milliseconds), contact (203.7 +/- 21.5 milliseconds); male, noncontact (199.4 +/- 26.7 milliseconds), limited contact (196.3 +/- 23.9 milliseconds), contact (195.0 +/- 23.8 milliseconds). Conclusions: Potentially clinically relevant differences existed in RTclin for sex and sport type. These results provide normative data adjusting for these performance factors.