Is the King-Devick Test a Reliable Tool in Wheelchair Athletes? A Preliminary Prospective Study in Wheelchair Basketball

Objective: (1) To determine the reliability of the King-Devick (KD) test among wheelchair basketball athletes across a season and (2) to compare the KD test time changes among those with and without a clinically suspected concussion. Design: Prospective, observational study. Setting: Division 3 college athletics department. Participants: Twenty-nine intercollegiate wheelchair basketball athletes. Interventions: Athletes were prospectively monitored for concussions throughout the 2018 to 2019 season. King-Devick testing was completed preseason, midseason, postseason, and after clinically suspected concussions. Main Outcome Measures: Two-way random effects intraclass correlation coefficient (ICC) was calculated. Friedman's test and pairwise comparison with Bonferroni correction were used to compare for change over time. Mean KD times and changes were compared between athletes with and without suspected concussion. Results: The KD test demonstrated good test-retest reliability (ICC = 0.826). Among participants without a concussion, there was a significant decrease in the mean KD test time from preseason to midseason (-3.3 seconds; P = 0.0167) and preseason to postseason (-3.3 seconds; P = 0.0167). No change was seen from mid-to-post season. Six athletes had 7 suspected concussions. Each demonstrated an increase in the KD test time, with a mean increase from 44.3 +/- 9.5 seconds to 53.7 +/- 12.8 seconds. King-Devick test times returned to or below baseline by postseason. Conclusions: The KD test shows good reliability among wheelchair basketball athletes without a concussion. A learning effect is demonstrated initially but plateaus on subsequent testing. Unlike athletes without a concussion, players with a clinically suspected concussion showed an increase in the KD test time.