Reliability and Minimal Detectable Change of the Standardized Assessment of Reaction Time (StART).

Abstract

Post-concussion reaction time deficits are common, but existing assessments lack sport-related applicability. We developed the Standardized Assessment of Reaction Time (StART) to emulate simultaneous cognitive and motor function demands in sport, but its reliability is unestablished. To determine the intra-rater, inter-rater, and test-retest reliability of StART, and examine the dual-task effect, time effect, and relationships between StART and computerized and laboratory-based functional reaction time assessments. Prospective cohort study. Clinical laboratory. 20 healthy, physically active participants (age: 20.3±1.8 years; 60% female; 75% no concussion history). Participants completed StART, computerized reaction time (Stroop task via CNS Vital Signs), and laboratory-based jump landing and cutting reaction time under single-task and dual-task (subtracting by 6's or 7's) cognitive conditions at two testing sessions a median 7 days apart. We used Intraclass correlation coefficients, repeated-measure ANOVAs, and Pearson r correlations to address our aims. Overall good to strong inter-rater (ICC2,k range:0.83-0.97), intra-rater (ICC3,k range:0.91-0.98), and test-retest reliability (ICC3,k range:0.69-0.89) were observed. A significant reaction time assessment by cognitive condition interaction was present (p=0.018,ηp2=0.14), with StART having the largest dual-task effect. Main time effects for dual-task conditions were observed across all reaction time assessments (mean difference: -25ms;p=0.026,ηp2=0.08) for improved performance at the second testing session. No StART outcomes correlated with computerized reaction time (p>0.05), although some StART outcomes correlated with single-task (r-range:0.42-65) and dual-task (r-range:0.19-0.50) laboratory cutting reaction time. StART demonstrated overall reliable performance relative to other reaction time measures. Reliability coupled with a strong dual-task effect indicates StART is a valid measure for examining functional reaction time, and may have future utility for sport-related concussion return to play decision-making.