The clinical reaction time test as part of a standardised concussion assessment battery

Background: Concussion is a worldwide challenge and diagnosing, evaluating and monitoring injured athletes places a huge burden on even experienced clinicians. Each concussed athlete presents differently and each one should be treated individually. In an ideal world, enough resources should be available for neuropsychologists and neuropsychology tests to evaluate each athlete. In resource-limited areas, neuropsychologists are replaced by experienced clinicians for treating concussions; these clinicians use as many objective cognitive tests as are available. If computerised neuropsychology tests are unavailable, then low-cost, objective and fast sideline tests, like the clinical reaction time test, may be incorporated in the assessment battery protocol. No one test can be the sole cognitive assessment for recovery after a concussion. It is imperative that all these clinical tests practical limitations and benefits are known. Aims: This study’s primary aim was to compare the Sport Concussion Assessment Tool 3 (SCAT3) total score with the clinical reaction time test (RTClin). The secondary aim was to compare the two tests as recovery tracking evaluations in the days following a concussion. Methods: In one season (2014) a prospective cohort study of amateur collegiate rugby union players who suffered concussion (n = 46, mean age 21, range 18 to 33 years) out of 1 166 registered players were evaluated within 72 hours (Evaluation-1), then weekly (Evaluations 2 to 4) until they became asymptomatic (Evaluation-Asymptomatic) using the SCAT3 total score and RTClin tests. Results: Within the first 72 hours after a concussion the SCAT3 Score and the RTClin showed a moderately positive correlation of 0.47 (Spearman test) and p = 0.04. The Spearman correlation between asymptomatic athletes was poor (0.21 and p = 0.46). A comparison of the SCAT3 Score of the first evaluation (E-1, n = 19, mean 24, range 10 to 74) with the asymptomatic evaluation (EAsym, n = 14, mean 3.5, range 0 to 9) shows statistical significance (p < 0.01). The RTClin during E-1 (n = 19, mean 190 ms, range 168 to 258 ms) and, compared to E-Asym (n = 14, mean 179 ms, range 147 to 223 ms), came close to showing significance (p = 0.07). The recovery tracking showed the mean time for recovery as 6 days (n = 5, range 4 to 18 days). The SCAT3 Score for E-1 showed a mean of 24, E-Asym mean of 3 and mean iii iv difference of 18. The RTClin for E-1 showed a mean of 199 ms, E-Asym mean of 178 ms and a mean difference of 20 ms. There is a strong correlation of SCAT3 Score and RTClin over time, of 0.80, but p > 0.05. The recovery time correlation for SCAT3 Score was moderate (-0.56), but p > 0.05, and for RTClin recovery showed a strong correlation over time (-0.82), but also p > 0.05. Conclusions: In a low-resource environment with only clinical examinations, SCAT3 and RTClin as tools there is evidence that the SCAT3 Score and RTClin may be good sideline diagnostic or screening tools within the first 72 hours after concussion. When athletes become asymptomatic, the RTClin becomes more important for monitoring persistent cognitive impairment than the SCAT3 Score. Further research is needed with larger study populations to confirm the utility of the RTClin as part of a post-concussion assessment battery.