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

Abstract

Context 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. Objective 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. Design Prospective cohort study. Setting Clinical laboratory. Patients or Other Participants 20 healthy, physically active participants (age: 20.3±1.8 years; 60% female; 75% no concussion history). Main Outcome Measures 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. Results 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. Conclusions 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.