The McNemar Change Index worked better than the Minimal Detectable Change in demonstrating the change at a single subject level.

Abstract Objective To assess the agreement between the Rasch Change Index (RCI), Minimal Detectable Change (MDC) and McNemar Change Index (McCI), three statistics for demonstrating the patient’s improvement/deterioration. Study Design and Setting The Mini-BESTest (a balance scale developed with the Rasch analysis) was administered before and after rehabilitation to 315 neurological patients. The Mini-BESTest RCI was chosen as the criterion standard for detecting the patient’s improvement. Positive and negative likelihood ratios (PLR and NLR, respectively) were used to evaluate the MDC and McCI accuracy in identifying the patient’s improvement. Three different Mini-BESTest MDCs were assessed. Results One-hundred patients improved their Mini-BESTest according to the RCI. All three MDCs and the McCI were solid in ruling-out the patient’s improvement (NLR 5), while the smaller MDCs were not. Of the four indices, McCI was the most robust in case of missing items. Conclusion A patient stable according to the MDCs or McCI is actually stable according to the criterion standard. To be reasonably sure that the patient is actually improved, larger MDC values or the McCI should be preferred and the McCI is preferable if there are missing items.