Diagnostics and Ecological Validity of the Italian Version of the Parkinson’s Disease Cognitive Rating Scale

Introduction: This study aimed to assess the diagnostics and ecological validity of the Parkinson's Disease Cognitive Rating Scale (PD-CRS) within an Italian cohort of non-demented Parkinson's disease (PD) patients. Methods:N = 128 non-demented PD patients were administered the PD-CRS, Montreal Cognitive Assessment (MoCA), and Parkinson's Disease Cognitive Functioning Rating Scale (PD-CFRS). Receiver-operating characteristic analyses were performed to explore the diagnostics of both raw and adjusted PD-CRS scores, by operationalizing the positive state as a below-cut-off MoCA score. Correlational analyses were run to test the ecological validity of the PD-CRS against the PD-CFRS. Results: Both raw and adjusted PD-CRS scores accurately identified patients with a defective MoCA scores (AUC = 0.84-0.85), yielding optimal diagnostics. A cut-off of <73.93, as identified on demographically adjusted PD-CRS scores, yielded the best diagnostics (sensitivity = 0.70; specificity = 0.89; positive and negative predictive values = 0.83 and 0.79; positive and negative likelihood ratios: 6.23 and 0.37: number needed for screening utility: 0.78). The PD-CRS was related to the PD-CFRS (r(s) = -0.24; p = 0.018). Conclusions: The Italian PD-CRS is a diagnostically sound and ecologically valid screener for cognitive impairment in non-demented PD patients.