Minimal clinically important difference of modified dynamic gait index in people with neurological disorders

Background: The minimal clinically important difference (MCID) of modified Dynamic Gait Index (mDGI) has not yet been determined for People with Neurological Disorders (PwND). Research question: To establish the MCID of the mDGI to determine clinically meaningful improvement in balance and gait in PwND. Methods: In this longitudinal study from a randomised clinical trial, 55 participants both in and outpatients with neurological disorders, received fifteen 40-minute rehabilitation sessions. Inpatients received daily treatments over a period of three weeks while outpatients received three treatments/week over a period of five weeks. An anchor-based method using percentage rating of improvement in balance (Activities Balance Confidence scale, ABC) was used to determine the MCID of mDGI. The MCID was defined as the minimum change in mDGI total score (post – pre intervention) that was needed to perceive at least a 10 % improvement on the ABC scale. A Receiver Operating Characteristic curve was used to define the cut-off for the optimal MCID of the mDGI discriminating between improved and not improved participants. Results: The MCID of the mDGI total score was 6 points and Area under the Curve was 0.64. For the mDGI time sub-scores the MCID was 2 points and Area under the Curve was 0.6. Significance: The MCID of balance and gait improvement measured by mDGI was prudently establish at ≥7 points, meaning that this is the minimum improvement score PwND need to get to perceive a clinically relevant change in their balance and gait confidence. These reference values can be a tool incorporated into clinicians daily practice to interpret mDGI change scores helping to determine whether the intervention is effective; to develop clinical tailored intervention goals and to establish meaningful perceived change in PwND.