Reliable change indices for the Italian version of the Montreal Cognitive Assessment (MoCA) in non-demented Parkinson's disease patients.

Background: . The present study aimed at deriving regression-based reliable change indices (RCIs) for the Montreal Cognitive Assessment (MoCA) in an Italian cohort of non-demented Parkinson's disease (PD) patients.

Methods: N = 33 consecutive, non-demented PD patients were followed-up at a 5-to-8-month interval (M = 6.6; SD = 0.6) with the MoCA. Practice effects and test-retest reliability were assessed via dependent-sample t-tests and intra-class correlation (ICC) coefficients, respectively. RCIs were derived separately for raw and demographically adjusted MoCA scores according to a standardized regression-based approach by accounting for both baseline confounders (i.e., demographics, disease duration and Unified Parkinson's Disease Rating Scale scores) and retest interval.

Results: No practice effects were found (t(32) = 0.29; p = .778), with acceptable test-retest reliability being detected (ICC = 0.67). MoCA scores at T0 proved to be the only significant predictor of T1 MoCA performances within both the model addressing raw scores and that addressing adjusted scores (ps < 0.001).

Conclusions: The present study provides Italian practitioners and researchers with regression-based RCIs for the MoCA in non-demented PD patients, which can be reliably adopted for retest interval ≥ 5 and ≤ 8 months without encountering any practice effect.