The Wisconsin gait scale - The minimal clinically important difference.

Background: Wisconsin Gait Scale (WGS) is an observational tool for the evaluation of gait quality in individuals after stroke with hemiplegia. It is divided into four subscales, which assess a total of fourteen spatiotemporal and kinematic parameters of gait observed during the consecutive gait phases. However, the WGS score change indicative of important and clinically meaningful change has not been determined.

Research Question: The study has been designed to define the minimal clinically important difference (MCID) of the WGS.

Methods: Four methods were used to determine the MCID for the WGS in 50 participants who had experienced a stroke: anchor-based study, distribution-based study, linear regression analysis and specification of the receiver operating characteristic (ROC) curve.

Results: In the anchor-based study, the mean change score in the MCID group was 1.9 points (the first MCID estimate). In the distribution-based study, the standard error of measurement for the no-change group was 0.3 (the second MCID estimate). The slope of the regression line was 1.21 which means than 1-point change in the Barthel Index (BI) is associated with 1.21-point change in the WGS. This translates to 2.25 points change in the WGS with 1.85 points change in the BI (the third MCID estimate). The best cut-off point, determined with ROC curve, was the value corresponding to 1 point of change in the WGS (the fourth MCID estimate).

Significance: We established that the MCID of the WGS was 2.25 points, based on the largest of the four MCID estimates. The value 2.25 of the MCID can help clinicians and researchers determine if the change in the scores on the WGS is clinically important.

Clinical Trial Registration: Data are parts of the following clinical trial: ACTRN12617000436370.