Ankle inversion proprioception measured during landing in individuals with and without chronic ankle instability

Background: Research evidence has suggested that a more sensitive ankle proprioceptive testing method with higher ecological validity is needed for assessing proprioceptive deficits in individuals with chronic ankle instability (CAI). Objectives: (1) To determine the test–retest reliability of a novel ankle proprioception assessment tool, the Ankle Inversion Discrimination Apparatus for Landing (AIDAL); (2) To assess whether AIDAL scores were sufficiently sensitive to detect proprioceptive deficits in chronic ankle instability (CAI); and (3) To examine whether AIDAL scores correlated with Cumberland Ankle Instability Tool (CAIT) scores. Design: Cross-sectional study. Methods: The AIDAL was purpose-built to assess ankle discrimination in four positions of ankle inversion (10°, 12°, 14° and 16°) upon landing from a 10 cm drop. Area Under the Receiver Operating Curve (AUC) was employed as the ankle proprioceptive discrimination score. Seven-day test–retest reliability was evaluated with 23 university students (12 CAI and 11 non-CAI), and another 36 university students (18 CAI and 18 non-CAI) were in the comparison study. Results: The test–retest reliability ICC score for the whole group was 0.763 (95% CI = 0.519–0.892), which showed an excellent reliability level. ICC (3,1) was 0.701 for the non-CAI group (95%CI = 0.210–0.910) and 0.804 for the CAI group (95%CI = 0.451–0.939). The CAI group performed at a significantly lower level on the AIDAL assessment than the non-CAI group (0.777 ± 0.05 vs. 0.815 ± 0.05, F = 5.107, p = 0.03). The discriminative AUC value for the AIDAL test was 0.756 with a cut point of 0.819 (sensitivity = 0.733, specificity = 0.800). The MDC90 scores for CAI and non-CAI groups were both 0.04. Spearman's correlation showed that the CAIT scores were significantly correlated with the ankle proprioceptive discrimination scores (rho = 0.401, p = 0.015). Conclusion: The AIDAL showed good test–retest reliability for both non-CAI and CAI groups. Measuring