Reliability, internal consistency, and concurrent validity of a modified version of the dynamic gait index in people with vestibular disorders.

Background: People with vestibular disorders often have abnormalities in gait and balance. The Dynamic Gait Index (DGI) is a relatively effective clinical gait measure that has been validated for use in patients with vestibular disorders. The modified version of the DGI (M-DGI) is based on the original DGI.

Research Question: The objective of this study was to refine and test the clinical application of the M-DGI, and to investigate whether it is an effective indicator of dynamic gait in patients with vestibular disorders.

Methods: A reliability and validity study. All raters reviewed the instructions and scoring criteria for each M-DGI item prior to the initial test. The raters simultaneously scored two M-DGI tasks for the 75 subjects, and the two tasks were completed with an interval of two hours in-between. Reliability of total M-DGI scores was assessed using intraclass correlation coefficients (2,1). Internal consistency of the M-DGI was evaluated using Cronbach's alpha. Concurrent validity of the M-DGI with Dizziness Handicap Inventory (DHI) and Timed "Up & Go" Test (TUG) was assessed using Spearman's rank order correlation coefficient.

Results And Significance: Interrater and intrarater reliability of the total M-DGI scores were reflected by ICCs of 0.99 and 0.97. Internal consistency of the M-DGI score was 0.9975. Spearman's rank order correlation coefficient of the M-DGI score with the Dizziness Handicap Inventory (DHI) and the Timed "Up & Go" Test (TUG) was 0.72 and 0.65, respectively.The M-DGI demonstrates acceptable reliability, internal consistency, and concurrent validity for use as a clinical gait measurement for patients with vestibular disorders.