Background: Balance assessment is used by clinicians as part of athlete concussion screening. The King-Devick (K-D) Balance app is designed to provide an objective balance assessment value. The purpose of this study was to investigate the responsiveness of a balance assessment using the K-D Balance app.
Hypothesis: The K-D Balance app will demonstrate acceptable responsiveness for balance assessment.
Study design: Repeated-measures study.
Level of evidence: Level 5.
Methods: A convenience sample of 25 participants between the ages of 20 and 25 years completed testing procedures. A battery of balance tests using the K-D Balance app on an iPhone were conducted 1 week apart. After a 5-minute warm-up, 3 stances were assessed: double leg, tandem right, and tandem left. The K-D Balance app guided the test positions and test times. A value representing movement was generated by the app algorithm. Analysis included descriptive statistics along with intraclass correlation coefficient and minimal detectable change (MDC).
Results: The median score of the K-D test was 0.5 for session 1 and 0.4 for session 2. The ICC was 0.42 (95% CI, 0.04-0.70), and the MDC was 1.58.
Conclusion: The MDC value of 1.58 represents the threshold of meaningful change in balance, as measured with the K-D Balance app.
Clinical relevance: Clinicians can use the results of this study to objectively assess changes in balance over time using the K-D Balance app.
Keywords: brain concussion; mobile applications; postural balance; responsiveness.